Infectious Disease Project Gallery

Infectious Disease Project

Mission Statement
Antimicrobial Agents
Organ-Based Infections
Pathogen-Based Infections
Editing FAQ
Gallery

▸ Tick Gallery

* * *

American dog tick (wood tick) ● Blacklegged tick (deer tick) ● Brown dog tick ● Gulf Coast tick ● Lone star tick ● Rocky Mountain wood tick ● Western blacklegged tick

▸ STD Gallery

* * *

Bacterial vaginosis ● Chlamydia ● Genital Herpes ● Gonorrhea ● Pubic lice infestation ● Scabies ● Syphilis ● Trichomoniasis

▸ Parasite Gallery

## WikiDoc Infectious Disease Project — Gallery

##### Tick Gallery

American dog tick (wood tick) ● Blacklegged tick (deer tick) ● Brown dog tick ● Gulf Coast tick ● Lone star tick ● Rocky Mountain wood tick ● Western blacklegged tick

* * *

##### Sexually Transmitted Disease Gallery

Bacterial vaginosis ● Chlamydia ● Genital Herpes ● Gonorrhea ● Pubic lice infestation ● Scabies ● Syphilis ● Trichomoniasis

* * *

##### Parasite Gallery

The unnamed parameter 2= is no longer supported. Please see the documentation for {{columns-list}}.

* * *

### Tick Gallery

* * *

* American dog tick `Return to Top`

* Common name: American dog tick, wood tick
* Scientific name: Dermacentor variabilis
* Reservoir: small rodents (larvae and nymphs); dogs and mammals (adult ticks)
* Geographic distribution: Rocky Mountains, Pacific Coast
* Disease transmitted: Rocky Mountain spotted fever, tularemia

* American dog tick (Dermacentor variabilis)
Adapted from CDC

* Approximate distribution of the American Dog tick
Adapted from CDC

* * *

* Blacklegged tick `Return to Top`

* Common name: blacklegged tick, deer tick
* Scientific name: Ixodes scapularis
* Reservoir: small mammals and birds (larvae and nymphs); rodents and mammals (adult ticks)
* Geographic distribution: northeastern and upper midwestern United States
* Disease transmitted: anaplasmosis, babesiosis, Lyme disease

* Blacklegged tick (Ixodes scapularis)
Adapted from CDC

* Approximate distribution of the Blacklegged tick
Adapted from CDC

* * *

* Brown dog tick `Return to Top`

* Common name: brown dog tick
* Scientific name: Rhipicephalus sanguineus
* Reservoir: dogs (entire life cycle)
* Geographic distribution: throughout the U.S. and the world
* Disease transmitted: Rocky Mountain spotted fever

* Brown dog tick (Rhipicephalus sanguineus)
Adapted from CDC

* Approximate distribution of the Brown Dog tick
Adapted from CDC

* * *

* Gulf Coast tick `Return to Top`

* Common name: Gulf Coast tick
* Scientific name: Amblyomma maculatum
* Reservoir: birds and small rodents (larvae and nymphs); deer and other wildlife (adult ticks)
* Geographic distribution: coastal areas of the United States along the Atlantic coast and the Gulf of Mexico
* Disease transmitted: Rickettsia parkeri rickettsiosis

* Gulf Coast tick (Amblyomma maculatum)
Adapted from CDC

* Approximate distribution of the Gulf Coast tick
Adapted from CDC

* * *

* Lone star tick `Return to Top`

* Common name: lone star tick
* Scientific name: Amblyomma americanum
* Reservoir: birds and deer (larvae and nymphs); white-tailed deer (adult ticks)
* Geographic distribution: southeastern and eastern United States
* Disease transmitted: ehrlichiosis, tularemia, southern tick-associated rash illness

* Lone star tick (Amblyomma americanum)
Adapted from CDC

* Approximate distribution of the lone star tick
Adapted from CDC

* * *

* Rocky Mountain wood tick `Return to Top`

* Common name: Rocky Mountain wood tick
* Scientific name: Dermacentor andersoni
* Reservoir: small rodents (larvae and nymphs); large mammals (adult ticks)
* Geographic distribution: Rocky Mountain states
* Disease transmitted: Rocky Mountain spotted fever, tularemia

* Rocky Mountain wood tick (Dermacentor andersoni)
Adapted from CDC

* Approximate distribution of the Rocky Mountain Wood tick
Adapted from CDC

* * *

* Western blacklegged tick `Return to Top`

* Common name: western blacklegged tick
* Scientific name: Ixodes pacificus
* Reservoir: birds and small rodents (larvae and nymphs); deer and other mammals (adult ticks)
* Geographic distribution: Pacific coast of the United States
* Disease transmitted: anaplasmosis, Lyme disease

* Western blacklegged tick (Ixodes pacificus)
Adapted from CDC

* Approximate distribution of the Western Blacklegged tick
Adapted from CDC

* * *

### Sexually Transmitted Disease Gallery

* * *

* Bacterial vaginosis `Return to Top`

* This photomicrograph of a vaginal smear specimen depicts two epithelial cells, a normal cell, and an epithelial cell with its exterior covered by bacteria giving the cell a roughened, stippled appearance known as a “clue cell”. Clue cells are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

* This photograph depicted a single Gardnerella vaginalis, formerly Haemophilus vaginalis, or Corynebacterium vaginalis, bacterial colony. The vagina is normally colonized by Lactobacillus spp., which help to regulate the region’s pH, maintaining it in the low range, thereby, inhibiting the growth of potentially-pathogenic organisms. The Gram-positive Gardnerella vaginalis bacterium is one such organism, and is a common cause for bacterial vaginosis (BV). Adapted from CDC

* This photograph depicted a single Gardnerella vaginalis, formerly Haemophilus vaginalis, or Corynebacterium vaginalis, bacterial colony. The vagina is normally colonized by Lactobacillus spp., which help to regulate the region’s pH, maintaining it in the low range, thereby, inhibiting the growth of potentially-pathogenic organisms. The Gram-positive Gardnerella vaginalis bacterium is one such organism, and is a common cause for bacterial vaginosis (BV). Adapted from CDC

* This photomicrograph reveals bacteria adhering to vaginal epithelial cells known as “clue cells”. “Clue cells” are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

* This photomicrograph reveals bacteria adhering to vaginal epithelial cells known as “clue cells”. “Clue cells” are epithelial cells that have had bacteria adhere to their surface, obscuring their borders, and imparting a stippled appearance. The presence of such clue cells is a sign that the patient has bacterial vaginosis. Adapted from CDC

* * *

* * *

* Chlamydia `Return to Top`

* Under a relatively-low magnification of 63X, this Gram-stained photomicrograph of a vaginal specimen revealed the presence of squamous epithelial cells, polymorphonuclear leukocytes (PMNs), or white blood cells (WBCs), and numerous Gram-positive bacilli, or rods. Vaginal specimens are reviewed for many reasons including the Pap test, tests for STDs such as human papilloma virus (HPV) and Chlamydia trachomatis, as well as others. The vagina is normally home to a number of bacterial organisms, referred to as vaginal microbiota, or vaginal microflora, composed primarily of rod-shaped Lactobacillus spp., as well as others. Adapted from CDC

* Photomicrograph of Chlamydia trachomatis taken from a urethral scrape. Untreated, chlamydia can cause severe, costly reproductive and other health problems including both short- and long-term consequences, i.e. pelvic inflammatory disease (PID), infertility, and potentially fatal tubal pregnancy. Adapted from CDC

* This McCoy cell monolayer micrograph reveals a number of intracellular C. trachomatis inclusion bodies; Magnified 50X. The intracellular inclusion body represents the replication phase of the Chlamydia spp. organisms, whereupon, the reorganized reticulate body (RB) multiplies through binary fission into 100-500 new RBs, which mature into elementary bodies (EB). Adapted from CDC

* This image reveals a close view of a patient’s left eye with the upper lid retracted in order to reveal the inflamed conjunctival membrane lining the inside of both the upper and lower lids, due to what was determined to be a case of inclusion conjunctivitis, a type of conjunctival inflammation caused by the bacterium, Chlamydia trachomatis. Inclusion conjunctivitis, also known as chlamydial conjunctivitis, is more common in newborns. Symptoms include redness of the eye(s), swelling of the eyelids, and discharge of pus, usually 5 to 12 days after birth. Adapted from CDC

* This photomicrograph depicts HeLa cells infected with Type-A Chlamydia trachomatis, Magnified 400X. The cell line of choice is McCoy, however a particular strain of HeLa cells, i.e. HeLa 299-24, can be used to culture C. trachomatis. For identification, either iodine or fluorescent antibody (FA) stains are usually used. Adapted from CDC

* Under a low magnification of 12.5X, this photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections. Adapted from CDC

* This photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies; Magnified 50X. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections.Adapted from CDC

* This photomicrograph reveals McCoy cell monolayers with Chlamydia trachomatis inclusion bodies; Magnified 200X. Chlamydia, caused by Chlamydia trachomatis, is the most common bacterial sexually transmitted infection. Using cell cultures from the McCoy cell line is one methods implemented in diagnosing Chlamydial infections. Adapted from CDC

* * *

* * *

* Genital Herpes `Return to Top`

* Viewed from the right posterior-oblique view, the male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Here you see the patient’s feet from a left lateral perspective revealing papules on the dorsal surface of the left foot. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment. Adapted from CDC

* Viewed from the right posterior-oblique view, the male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

* This male patient presented with maculopapular lesions on the distal penile shaft that were first thought to be due to syphilis, but through the process of conducting a differential diagnosis, was later determined to be due to a Herpesviridae infection. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.Adapted from CDC

* This was a posterior view of the back and buttocks of a male patient, in a clinical setting, who had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

* The male patient depicted here was in bed, in a clinical setting, and had presented with a pancorporeal maculopapular rash, which was initially thought to be a possible case of smallpox, but which later, was diagnosed as herpes simplex. See PHIL 15819, for another view of this patient in the same setting. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. The virus can become disseminated, as was the case here, usually involving patients who are immunocompromised such as in the case of AIDS, or undergoing chemotherapeutic treatment.Adapted from CDC

* This image depicts the right foot of an infant born with a herpes simplex infection, known as neonatal herpes, or herpes simplex neonatorum, which had manifested itself through the development of maculopapular lesions of the foot’s heal and sole. See PHIL 6510, for another view of this condition.Adapted from CDC

* This image depicts the perineal region of a male patient which displayed a perianal mucocutaneous lesion caused by a herpes simplex infection. Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) or type 2 (HSV-2). Most genital herpes is caused by HSV-2. Most individuals have no or only minimal signs or symptoms from HSV-1 or HSV-2 infection. When signs do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Typically, another outbreak can appear weeks or months after the first, but it almost always is less severe and shorter than the first outbreak. Although the infection can stay in the body indefinitely, the number of outbreaks tends to decrease over a period of years. Adapted from CDC

* This neonate displayed a maculopapular outbreak on his feet due to congenitally acquired herpes simplex virus. In this instance, due to the age of the patient, this condition is known as herpes simplex neonatorum. See PHIL 15115, for a closer view of these lesions. Genital HSV can cause potentially fatal infections in babies. It is important that women avoid contracting herpes during pregnancy because a first episode during pregnancy causes a greater risk of transmission to the baby. If a woman has active genital herpes at delivery, a cesarean delivery is usually performed. Fortunately, infection of a baby from a woman with herpes infection is rare.Adapted from CDC

* This 7 year old child with a history of recurrent herpes labialis presented with a periocular herpes simplex vesicular outbreak. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. Adapted from CDC

* This patient presented with what were recurrent characteristic vesiculopapular herpes simplex lesions on his anterior thigh. These early vesiculopapular herpetic lesions on the anterior thigh (Cntr) had yet to rupture. Herpes simplex virus is a member of a group of viruses including those which cause oral herpes (usually HSV-1), and genital herpes (usually HSV-2). Adapted from CDC

* This male presented with primary vesiculopapular herpes genitalis lesion at the base of his penis due to the HSV-2 serotype. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.

* This patient presented with what was diagnosed as a herpes genitalis outbreak on the penile shaft due to HSV-2. Genital herpes is a sexually transmitted disease caused by the herpes simplex viruses type 1 (HSV-1), and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Symptoms typically include one or more blisters on or around the genitals or rectum. Adapted from CDC

* This patient presented with what was diagnosed as a herpes genitalis outbreak on the penile shaft due to HSV-2. Genital herpes is a sexually transmitted disease caused by the herpes simplex viruses type 1 (HSV-1), and type 2 (HSV-2). Most genital herpes is caused by HSV-2. Symptoms typically include one or more blisters on or around the genitals or rectum. Adapted from CDC

* This patient presented with what was differentially diagnosed as a herpes genitalis outbreak on the penile glans and shaft. Note that what at first appears as erythematous areas are actually coalescence of herpes genitalis “micro-ulcers”. Genital herpes is a sexually transmitted disease (STD) caused by the herpes simplex viruses type 1 (HSV-1) and type 2 (HSV-2). Adapted from CDC

* This male presented with primary vesiculopapular herpes genitalis lesions on his glans penis, and penile shaft. When signs of herpes genitalis do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur.

* This 7 year old child with history of recurrent herpes labialis presented with a periocular herpes simplex vesicular outbreak. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes (herpes labialis), i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.Adapted from CDC

* This male patient presented with a maculopapular herpetic rash on the penile shaft and corona of the glans penis. When signs of genital herpes do occur, they typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they appear. Adapted from CDC

* This 7 year old child presented with a generalized herpes simplex vesiculopapular rash over his trunk 5 days after onset. Herpes simplex virus, otherwise known as Herpesvirus hominis is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2.

* This patient presented with a generalized Herpes hominis vesiculopapular rash over the dorsum of the left foot. Herpesvirus hominis, otherwise known as “herpes simplex virus” is a member of a group of viruses including those which cause oral herpes, i.e., usually HSV-1, and genital herpes, i.e., usually HSV-2. Adapted from CDC

* This was an outbreak of herpes genitalis manifested as blistering around the vaginal introitus due to the HSV-2 virus. The sexually transmitted herpes simplex virus type-2 (HSV-2) typically causes one or more blisters to form on, or around the genitals or rectum, which break, leaving tender ulcers that may take 2-4 wks to heal after making their initial appearance.Adapted from CDC

* Herpes simplex ulcerations on the lateral plantar surface of an infant’s foot. Women who acquire genital herpes during pregnancy can transmit the virus to their babies. Untreated Herpes Simplex Virus (HSV) infections in newborns can result in mental retardation and death.Adapted from CDC

* Blisters on the vulva due to a recurring Herpes II (HSV-2) virus infection. Symptoms from HSV-1 or HSV-2 infection, when signs do occur, typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur. Adapted from CDC

* Blisters on the penis due to a recurring Herpes II (HSV-2) virus infection. Symptoms from HSV-1 or HSV-2 infection, when signs do occur, typically appear as one or more blisters on or around the genitals or rectum. The blisters break, leaving tender ulcers (sores) that may take two to four weeks to heal the first time they occur.Adapted from CDC

* * *

* * *

* Gonorrhea `Return to Top`

* This 1970 photograph revealed the presence of what was determined to be a secondary gonococcal lesion located on the distal finger tip of a patient who presented with a case of gonorrhea. Usually, secondary gonococcal lesions manifest themselves when a primary infection of the urogenital tract becomes disseminated throughout the body by way of the circulatory system.

* This 1970 photograph revealed the presence of what was determined to be a gonococcal infection involving the cervix of a patient who presented with a case of gonorrhea. Note that there is a purulent discharge emanating from the cervical os, and pooling in the vagina.Adapted from CDC

* This gonorrhoeae patient presented with gonococcal arthritis of the hand, which caused the hand and wrist to swell due to bacterium Neisseria gonorrhoeae. Adapted from CDC

* This gonococcal arthritic patient presented with an inflammation of the skin of her right arm due to a disseminated Neisseria gonorrhoeaebacterial infection. Adapted from CDC

* This patient presented with a cutaneous gonococcal lesion due to a disseminated Neisseria gonorrhea bacterial infection. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations. Adapted from CDC

* This colposcopic view of this patient’s cervix reveled an eroded ostium due to Neisseria gonorrhea infection. A chronic Neisseria gonorrhea infection can lead to complications, which can be apparent such as this cervical inflammation, and some can be quite insipid, giving the impression that the infection has subsided, while treatment is still needed.Adapted from CDC

* This patient presented with a lesion of the right hand due to a disseminated Neisseria gonorrhoeae bacteremia. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations.Adapted from CDC

* This patient presented with urogenital complications from a case of gonorrhea including penile paraphimosis. Due to the accompanying inflammation brought on by the Neisseria gonorrhoeae infection, the foreskin becomes adherent to the glans penis resulting in a condition known as phimosis, and cannot be retracted in order to expose the entire glans. Adapted from CDC

* This patient presented with a paraurethral abscess due to the spread of N. gonorrhoeae bacteria. In this case, the spread of the bacterial pathogen from its initial urethral site of origin to the surrounding penile tissues brought on the formation of an abscess, which was one of three that had formed in this manner.Adapted from CDC

* This patient presented with cutaneous foot lesions that were diagnosed as a disseminated gonococcal infection. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

* This patient presented with a cutaneous lesion that was traced to a systemically disseminated gonoccal infection. Though a sexually transmitted disease, if a Gonorrhea infection is allowed to go untreated, the Neisseria gonorrhea bacteria responsible for the infection can become disseminated throughout the body, forming lesions in extra-genital locations.Adapted from CDC

* Here, a specimen is about to be collected from this patient who presented with symptoms including a penile discharge. Most Neisseria and related species are normal flora in humans and animals, however, some species such as N. gonorrhoeae are pathogens in normal hosts and those species known to be commensal, may be opportunistic pathogens. Adapted from CDC

* This patient presented with a cutaneous lesion on the palm of his right hand due to a N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body. Adapted from CDC

* His patient presented with cutaneous lesions on his left ankle and calf due to a disseminated N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

* This patient presented with cutaneous lesions on the right forearm and left hand due to a N. gonorrhoeae infection. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

* This patient presented with ophthalmic inflammation that was diagnosed as gonococcal conjunctivitis. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as cutaneous ulcerations or conjunctival inflammation.

* A highly contagious infection, gonococcal ophthalmia is due the pathogenic bacteria Neisseria gonorrhoeae. This case involved an adult patient with a systemically disseminated gonococcal infection, but neonates are in danger of acquiring this ophthalmic infection at the time of their delivery when the mother is infected with N. gonorrhoeae bacteria.Adapted from CDC

* This case of gonorrheal conjunctivitis resulted in partial blindness due to the spread of N. gonorrhoeae bacteria. Gonococci cause both localized infections, usually in the genital tract, and disseminated infections with seeding of various organs. Diagnosis of localized infections depends on Gram-staining, and culture of the discharge.Adapted from CDC

* The early lesion on this patient’s left index finger was due to the systemic dissemination of N. gonorrhoeae bacteria. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

* The lesion on this patient’s left hand was due to the systemic dissemination of the Neisseria gonorrhoeae bacteria. Though sexually transmitted, and involving the urogenital tract initially, a Neisseria gonorrhoeae bacterial infection can become disseminated systemically, manifesting itself as a cutaneous erythematous lesion anywhere on the body.Adapted from CDC

* The lesion on this patient’s heel was due to the systemic dissemination of the N. gonorrhoeae bacteria. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

* Note the cloudiness of this patient's right eye in this case of gonococcal conjunctivitis due to N. gonorrhoeae bacteria. Gonococcal conjunctivitis in caused by a direct inoculation of the conjunctival membrane of the eye with Neisseria gonorrhoeae bacteria, causing this membrane covering the eye to become inflamed, edematous, and produce a purulent exudate.Adapted from CDC

* This patient presented with a penile meatal discharge which was diagnosed as gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is stripped towards the orifice to express some pus. A thin sterile swab is then inserted 23 cm into the urethra and rotated before being withdrawn.Adapted from CDC

* This patient presented with a case of gonorrhea with symptoms including cervicitis and vaginal discharge. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

* This male presented with purulent penile discharge due to gonorrhea with an overlying penile pyodermal lesion. Pyoderma involves the formation of a purulent skin lesion as in this case located on the glans penis, and overlying the sexually transmitted disease gonorrhea. Adapted from CDC

* This male presented with a purulent penile discharge due to gonorrhea with an overlying penile pyodermal lesion. Pyoderma involves the formation of a purulent skin lesion, in this case located on the glans penis, and overlying the sexually transmitted disease gonorrhea.Adapted from CDC

* This patient presented with symptoms later diagnosed as due to Gonococcal pharyngitis.Gonococcal pharyngitis is a sexually-transmitted disease acquired through oral sex with an infected partner. The majority of throat infections caused by gonococci have no symptoms, but some can suffer from mild to severe sore throat.Adapted from CDC

* This technician is collecting a specimen from a male suspected of having gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is “stripped” towards the orifice to express some pus. A thin sterile swab is then inserted 23cm into the urethra and rotated before being withdrawn. Adapted from CDC

This technician is collecting a specimen from a male suspected of having gonorrhea. When collecting a male specimen, if no discharge is evident, the urethra is “stripped” towards the orifice to express some pus. A thin sterile swab is then inserted 23cm into the urethra and rotated before being withdrawn. Adapted from CDC

* This patient presented with a gonorrheal ecthyma on the skin due to systemically disseminated N. gonorrhoeae bacteria. An ecthyma is a cutaneous eruption consisting of a large, round pustule on an inflamed base caused by untreated gonococcal bacteria spread systemically throughout the bloodstream.Adapted from CDC

* This was a skin lesion on a patient with gonorrhea due to the systemic spread of N. gonorrhoeae bacteria. Gonorrhea is caused by Neisseria gonorrhoeae. If left untreated, will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

* This was a newborn with gonococcal ophthalmia neonatorum caused by a maternally transmitted gonococcal infection. Unless preventative measures are taken, it is estimated that gonococcal ophthalmia neonatorum will develop in 28% of infants born to women with gonorrhea. It affects the corneal epithelium causing microbial keratitis, ulceration and perforation.Adapted from CDC

* This patient with diagnosed gonococcal urethritis presented with unilateral gonococcal conjunctivitis. See PHIL 16400, for the appearance of her eye 24 hours following treatment with 4.8 million units of aqueous procaine penicillin G (APPG) and probenicid. If untreated N. gonorrhoeae bacteria may spread to the bloodstream, and thereby, throughout the body. The most common symptoms are then rash and joint pains, but other generalized symptoms may result as well such as conjunctivitis.Adapted from CDC

* This patient presented with gonorrhea and a disseminated gonococcal skin infection about the ankle. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

* This is a photograph of a skin lesion on a patient diagnosed with gonorrhea. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

* This is a skin lesion in a patient with systemically disseminated Neisseria gonorrhoeae bacteria. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such fully systemic dissemination may manifest itself as skin lesions throughout the body.Adapted from CDC

* Here a technician is about to collect an intraurethral specimen to be tested for gonorrhea, or non-specific urethritis. Doctors or other health care workers usually use three laboratory techniques to diagnose gonorrhea: staining samples directly for the bacterium, detection of bacterial genes or DNA in the urine, and growing the bacteria in laboratory cultures.Adapted from CDC

* This photograph shows the collection of a specimen from a male suspected of having gonorrhea.When collecting a male specimen, if no discharge is evident, the urethra is stripped towards the orifice to express some pus. A thin sterile swab is then inserted 23 cm into the urethra and rotated before being withdrawn.Adapted from CDC

* The foot of this patient is swollen due to gonococcal arthritis. Gonorrhea is the most frequently reported communicable disease in the U.S. Disseminated gonococcal infection is most often the cause of acute septic arthritis in sexually active adults, and the reason for most hospitalizations due to infective arthritis.Adapted from CDC

* Note the gonococcal lesion on the skin of the left arm due to the bacterium Neisseria gonorrhoeae. N. gonorrhoeae, a gram-negative diplococcus, is the causative agent for Gonorrhea. Though these bacteria can infect the genital tract, the mouth, and the rectum, they can become disseminated throughout a person’s bloodstream. Adapted from CDC

* Close-up of a gonococcal lesion on the skin of a patient’s arm. Gonorrhea, caused by Neisseria gonorrhoeae, if left untreated will enter the blood, thereby, spreading throughout the body. As is shown here, such full body dissemination may manifest itself as skin lesions in the form of gray pustules. Adapted from CDC

* * *

* * *

* Pubic lice infestation `Return to Top`

* This 2006 image depicted five body lice, Pediculus humanus var. corporis, which from left to right included three nymphal-staged lice, beginning with a stage N1, then N2, and thirdly a N3-staged nymph, followed by an adult male louse, and finally an adult female louse. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus capitis (head louse), Pediculus humanus corporis (body louse, clothes louse) and Phthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

* This photomicrograph depicts a dorsal view of an adult female human head louse, Pediculus humanus capitis. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus capitis (head louse), Pediculus humanus corporis (body louse, clothes louse) and Pthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations (pediculosis and pthiriasis) are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

* This illustration depicts a dorsal view of a “crab louse”, Phthirus pubis, a member of the suborder Anoplura, or “sucking lice”. The crab louse Phthirus pubis, is not known to carry disease producing organisms. Infestations usually occur in the pubic region of humans, and may occasionally be found on other coarse body hair, such as hair on the legs, armpits, mustache, beard, eyebrows, or eyelashes. Infestations of young children are usually on the eyebrows or eyelashes. Lice found on the head are not pubic lice; they are head lice. Adapted from CDC

* This illustration depicts some of the morphologic differences seen in two “sucking lice” of the Order Annoplura. The louse on the left is a “body louse”, Pediculus humanus var. corporis, and the louse on the right is a “crab” or “pubic louse”, Phthirus pubis. Note that both of these lice are wingless, and possess three pairs of claw-tipped legs, which allows them to firmly grasp the hair shafts to which they remain attached as human ectoparasitic pests. Adapted from CDC

* This photograph reveals the presence of crab lice, Phthirus pubis with reddish-brown crab feces. Pubic lice are generally found in the genital area on pubic hair; but may occasionally be found on other coarse body hair, such as hair on the legs, armpit, mustache, beard, eyebrows, and eyelashes. Adapted from CDC

* This is an illustration comparing the Head Louse, Pediculus humanus, with the Pubic Louse, Phthirus pubis. These insects use their hook-like appendages to grasp unto the hair shafts of their hosts in body regions unique to its species, i.e. the head louse infests the head region of its host, while the pubic louse infests its host’s pubic region. Adapted from CDC

* This patient presented with an infestation of Phthirus pubis, or crab lice. A Phthirus pubis infestation has caused the erythematous lesions seen in the pubic region of this patient in response to the bites of the crab lice arthropods. Adapted from CDC

* This image depicts a dorsal view of a female head louse, Pediculus humanus var. capitis. Lice are parasitic insects that can be found on people's heads, and bodies, including the pubic area. Human lice survive by feeding on human blood. Lice found on each area of the body are different from each other. The three types of lice that live on humans are: Pediculus humanus var. capitis (head louse), Pediculus humanus var. corporis (body louse, clothes louse) and Pthirus pubis ("crab" louse, pubic louse). Only the body louse is known to spread disease. Lice infestations (pediculosis and pthiriasis) are spread most commonly by close person-to-person contact. Dogs, cats, and other pets do not play a role in the transmission of human lice. Lice move by crawling; they cannot hop or fly. Both over-the-counter and prescription medications are available for treatment of lice infestations. Adapted from CDC

* * *

* * *

* Scabies `Return to Top`

* Under a moderate modification, this photomicrograph revealed the histopathologic changes in a human skin sample from the site of a number of scabies burrows, due to an infestation of Sarcoptes scabiei var. hominis. Note that the scabies had burrowed into the upper layers of this patient’s skin, into the epidermis, superficial to the stratum basale, also known as the stratum germinativum. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

* This image depicts the anterior aspect of a patient’s lower legs, either of which displaying the pathologic consequences of an infestation of Sarcoptes scabiei var. hominis, otherwise known as scabies. Of note, were the secondary severe excoriations, resulting from the patient having scratched at the primary maculopapular rash caused by the scabies bites. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

* This close view of the genitalia of a male patient reveals the presence of erosive, inflamed lesions, which had been caused by an infestation of scabies, Sarcoptes scabiei var. hominis. The lesions are on the penile glans, and the preputial skin. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

* This photograph depicting the dorsal surface of a human hand focused on the interdigital web space between the index and middle fingers, and revealed the presence of papules due to an infestation of the human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

* The right axillary region of this male patient exhibited a papular rash, which had been caused by an infestation of the human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies. The most common signs and symptoms of scabies are intense itching (pruritus), especially at night, and a pimple-like (papular) itchy rash. The itching and rash each may affect much of the body or be limited to common sites such as the wrist, elbow, armpit, webbing between the fingers, nipple, penis, waist, belt-line, and buttocks. The rash also can include tiny blisters (vesicles) and scales. Scratching the rash can cause skin sores; sometimes these sores become infected by bacteria. Adapted from CDC

* This photomicrograph reveals a single human itch mite, Sarcoptes scabiei var. hominis, otherwise commonly known as scabies, that had burrowed itself into the epidermal layers of a skin tissue sample extracted from an unknown host. The microscopic scabies mite burrows into the upper layer of the skin where it lives and lays its eggs. The most common symptoms of scabies are intense itching and a pimple-like skin rash. The scabies mite usually is spread by direct, prolonged, skin-to-skin contact with a person who has scabies. Scabies occurs worldwide and affects people of all races and social classes. Scabies can spread rapidly under crowded conditions where close body contact is frequent. Institutions such as nursing homes, extended-care facilities, and prisons are often sites of scabies outbreaks. Adapted from CDC

* This woman presented with a rash composed of pimple-like irritations on the abdomen and thorax due to canine scabies. If an animal is infested with scabies, or mange, and comes in close contact with humans, the mites can get under the skin causing itching and irritation. However, this form of scabies is mild, and the mites die in a couple of days without reproducing. Adapted from CDC

* * *

* * *

* Syphilis `Return to Top`

* This image depicts the soles of both feet of a syphilis patient revealing the presence of secondary syphilitic lesions consisting of erosive dermal regions of the toes, mainly involving the intertriginous spaces between the toes. Secondary syphilitic lesions consist of skin rashes and/or sores in the mouth, vagina, or anus (also called mucous membrane lesions) mark the secondary stage of symptoms. This stage usually starts with a rash on one or more areas of the body. Rashes associated with secondary syphilis can appear from the time when the primary sore is healing to several weeks after the sore has healed. The rash usually does not cause itching. This rash may appear as rough, red, or reddish brown spots both on the palms of the hands and/or the bottoms of the feet. However, this rash may look different on other parts of the body and can look like rashes caused by other diseases Large, raised, gray or white lesions may develop in warm, moist areas such as the mouth, underarm or groin region. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. Other symptoms of secondary syphilis include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The symptoms of secondary syphilis will go away with or without treatment. Without appropriate treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicted the umbilicus of an infant, which displayed an inflamed lesion that under a darkfield examination revealed the presence of Treponema pallidum spirochetes, and hence, a diagnosis of congenital syphilis. Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases. It is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying. Syphilis cannot be spread through contact with toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing, or eating utensils.
Adapted from CDC

* With a VDRL (Venereal Disease Research Laboratory) titer of 1:128, this syphilis patient displayed symptoms indicative of the onset of the secondary stage of this disease, which included generalized lymphadenopathy, and accompanying lingual (tongue) mucous patches. Syphilis is a sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases. It is passed from person to person through direct contact with a syphilis sore. Sores occur mainly on the external genitals, vagina, anus, or in the rectum. Sores also can occur on the lips and in the mouth. Transmission of the organism occurs during vaginal, anal, or oral sex. Pregnant women with the disease can pass it to the babies they are carrying. Syphilis cannot be spread through contact with toilet seats, doorknobs, swimming pools, hot tubs, bathtubs, shared clothing, or eating utensils.
Adapted from CDC

* This image depicts the dorsal surface of the tongue in the case of an elderly African-American male, due to what was determined to be a secondary syphilitic infection. Note the furrowed appearance, and the papillae-free, i.e., desquamated, smooth lingual surface. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This close-up view demonstrates the interior oral cavity of an elderly African-American male patient, revealing a perforated hard palate due to what was a congenital syphilis infection. At the time of this photograph, the patient was being treated for both active syphilis, and gonorrhea infections. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This close-up view demonstrates the dentition within the oral cavity of a young African-American female patient, revealing the triangular-shaped deformity of her right lateral incisor, and the left central incisor, which is known as Hutchinson incisors, and is caused by a congenital syphilitic infection. In this particular case, at the time of her birth, one of this woman’s parents tested positive for syphilis. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This image depicts a close view of the right corner, i.e., angle, of the mouth of an African-American female, upon which one can see a circular lesion that was diagnosed as a primary syphilitic chancre. The primary stage of syphilis is usually marked by the appearance of a single sore (called a chancre), but there may be multiple sores. The time between infection with syphilis and the start of the first symptom can range from 10 to 90 days (average 21 days). The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body. The chancre lasts 3 to 6 weeks, and it heals without treatment. However, if adequate treatment is not administered, the infection progresses to the secondary stage.
Adapted from CDC

* This image depicts a close view of the surface of an African-American female’s tongue, upon which one can see a circular lesion that was diagnosed as a primary syphilitic chancre. The primary stage of syphilis is usually marked by the appearance of a single sore (called a chancre), but there may be multiple sores. The time between infection with syphilis and the start of the first symptom can range from 10 to 90 days (average 21 days). The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body. The chancre lasts 3 to 6 weeks, and it heals without treatment. However, if adequate treatment is not administered, the infection progresses to the secondary stage.
Adapted from CDC

* This photograph depicts the destruction of a patient’s left knee joint, which was determined to be a case of neuropathic arthropathy, also known as Charcot’s joint, brought on by a tertiary syphilitic infection. See PHIL 12606, for a radiographic view (x-ray) of a patient's knee with this arthritic deformity. Late and Latent Stages: The latent (hidden) stage of syphilis begins when primary and secondary symptoms disappear. Without treatment, the infected person will continue to have syphilis even though there are no signs or symptoms; infection remains in the body. This latent stage can last for years. The late stages of syphilis can develop in about 15% of people who have not been treated for syphilis, and can appear 10-20 years after infection was first acquired. In the late stages of syphilis, the disease may subsequently damage the internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints. Signs and symptoms of the late stage of syphilis include difficulty coordinating muscle movements, paralysis, numbness, gradual blindness, and dementia. This damage may be serious enough to cause death.
Adapted from CDC

* This photograph depicts a patient’s face revealing pathologic cutaneous changes in the region around the nose and mouth, consisting of noduloulcerative lesions, known as syphilids, due to a syphilitic infection. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This photograph depicts the a patient’s opened mouth revealing pathologic changes in the superior mucosal surface of his tongue known as syphilitic glossitis, due to a congenital syphilitic infection. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This photograph depicts the wrinkled skin around a patient’s nose and mouth known as “rhagades”, due to a congenital syphilitic infection. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This image depicts an inferior, intraoral view of a patient’s hard palate revealing the pathologic changes in palatal anatomy, which resulted in a perforation into the nasal cavity, and was due to a congenital syphilitic infection. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This image depicts a close view of the right eye of a patient revealing the pathologic changes in her cornea known as interstitial corneal keratitis, which was due to a congenital syphilitic infection, and is a chronic progressive keratitis of the corneal stroma, i.e., connective tissue matrix, often resulting in blindness and frequently associated with congenital syphilis. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This image depicts the dentition of a congenital syphilis patient, who due to this disease, went on to develop what are known as Hutchinson’s teeth, in which case the teeth are widely spaced, and the bite surfaces of the incisors are notched. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* This photograph depicts a lateral view of a patient's right knee, who'd been diagnosed with "Clutton’s joints" due to what was determined to be congenital syphilis. See PHIL 4102, for a view of the patient's knees, from an anterior persoective. ”Clutton's joints”, or symmetrical hydrarthrosis of the knee joints, is a painless condition that often occurs during the late stages of congenital syphilis. It involes synovitis, or swelling of a joint, accompanied by collections of fluid within the joint capsule.
Adapted from CDC

* This image depicts the perineal region and upper thighs of an infant born with what was diagnosed as congenital syphilis. In this particular case, one will note the presence of early cutaneous syphilids. How does syphilis affect a pregnant woman and her baby: The syphilis bacterium can infect the baby of a woman during her pregnancy. Depending on how long a pregnant woman has been infected, she may have a high risk of having a stillbirth (a baby born dead) or of giving birth to a baby who dies shortly after birth. An infected baby may be born without signs or symptoms of disease. However, if not treated immediately, the baby may develop serious problems within a few weeks. Untreated babies may become developmentally delayed, have seizures, or die. Infants born to mothers who have reactive nontreponemal and treponemal test results should be evaluated with a quantitative nontreponemal serologic test (RPR or VDRL) performed on infant serum because umbilical cord blood can become contaminated with maternal blood and could yield a false-positive result. Conducting a treponemal test (i.e., TP-PA or FTA-ABS) on a newborn’s serum is not necessary. No commercially available immunoglobulin (IgM) test can be recommended. All infants born to women who have reactive serologic tests for syphilis should be examined thoroughly for evidence of congenital syphilis (e.g., nonimmune hydrops, jaundice, hepatosplenomegaly, rhinitis, skin rash, and/or pseudoparalysis of an extremity). Pathologic examination of the umbilical cord by using specific fluorescent antitreponemal antibody staining is suggested. Darkfield microscopic examination or DFA staining of suspicious lesions or body fluids (e.g., nasal discharge) also should be performed.
Adapted from CDC

* This image depicts the perineal region of a male patient, who’d presented with what was described as eroded, moist, papular intertrigo, due to what was diagnosed as a case of secondary syphilis. Intertrigo is an inflamed area of a skin fold where two skin surfaces touch one another, such as here, in the gluteal cleft between the buttocks. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the left axillary region of a female patient, who’d presented with what was described as condylomata lata lesions, due to what was diagnosed as a case of secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the perineal region of a female patient, who’d presented with what was described as perianal condylomata lata lesions, due to what was diagnosed as a case of secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the perineal region of a patient, who’d presented with what was described as moist papular and nodular perianal syphilids, due to what was diagnosed as a case of secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the tongue of a patient, who’d presented with what was described as a number of syphilitic mucous patches, due to what was diagnosed as secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the upper half of a patient’s face, who’d presented with what was described as syphilitic alopecia, which had caused thinning of the eyebrows, due to what was diagnosed as secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the posterior scalp of a patient, who’d presented with what was described as “motheaten” alopecia, due to what was diagnosed as secondary syphilis. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the palms of a patient's hands, who’d presented with an outbreak of palmar syphilids, due to what was diagnosed as a secondary syphilitic infection. Note that some of the rash sparsely included areas of her forearms, as well. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This image depicts the soles of a patient's feet, who’d presented with an outbreak of plantar syphilids, due to what was diagnosed as a secondary syphilitic infection. The secondary stage of syphilis is characterized by the manifestation of a skin rash and mucous membrane lesions. This stage typically starts with the development of a rash on one or more areas of the body. The rash usually does not cause itching. Rashes associated with secondary syphilis can appear as the chancre is healing or several weeks after the chancre has healed. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and possibly late stages of disease.
Adapted from CDC

* This photograph shows a penile chancre due to a primary syphilitic infection caused by Treponema pallidumbacteria. The primary stage of syphilis is usually marked by the appearance of a sore called a chancre. The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body, and lasts 3-6 weeks, healing on its own.
Adapted from CDC

* This patient presented with a primary syphilitic chancre on the ventral side of the penile glans and shaft. The primary stage of syphilis is usually marked by the appearance of a sore called a chancre. The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body, and lasts 3-6 weeks, healing by itself.
Adapted from CDC

* This photograph shows a penile chancre due to his primary syphilitic infection caused by Treponema pallidum bacteria. The primary stage of syphilis is usually marked by the appearance of a sore called a chancre. The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body, and lasts 3-6 weeks, healing on its own.
Adapted from CDC

* Though initially thought to be herpes lesions, the differential diagnostic process showed these to be syphilitic in nature. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.
Adapted from CDC

* This patient presented with a penile lesion, which under darkfield microscopic examination was found to be due to syphilis. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* This patient with a primary staged syphilis infection presented with phimosis of the penile foreskin. Due to the formation of a primary syphilitic chancre, adhesions developed affixing the foreskin to the glans penis resulting in a condition known as phimosis, where the foreskin cannot be retracted in order to expose the entire glans.

* This patient presented with a Moon’s Molar or Mulberry Molar due to a congenital syphilitic infection. Moon's- or Mulberry Molar is a condition where the first lower molar tooth has become dome-shaped due to malformation by congenital syphilis.
Adapted from CDC

* This patient presented with a primary vulvar syphilitic chancre due to Treponema pallidum bacteria. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* This patient presented with an anal chancre due to Treponema pallidum bacteria. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* This patient presented with a case of syphilis during the secondary stage with the appearance of a papular forearm lesion. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment the rash clears up on its own.
Adapted from CDC

* This patient presented with a case of alopecia during the secondary stage of syphilis. Second-stage symptoms can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and tiredness. The disease can easily be passed to sex partners during the primary or secondary stages.
Adapted from CDC

* This patient presented with a case of alopecia during the secondary stage of syphilis. Second-stage symptoms can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and tiredness. The disease can easily be passed to sex partners during the primary or secondary stages.
Adapted from CDC

* This patient presented with a case of alopecia due to what was determined to be secondary syphilis. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment the rash clears up on its own.
Adapted from CDC

* This patient presented with a gumma of nose due to a long standing tertiary syphilitic Treponema palliduminfection. Without treatment, an infected person still has syphilis even though there are no signs or symptoms. It remains in the body, and it may begin to damage the internal organs, including the brain, nerves, eyes, heart, blood vessels, liver, bones, and joints.
Adapted from CDC

* This 16 year old patient presented with a "saddle nose" deformity due to a congenital syphilitic condition. See PHIL 17626, for a color version of this image. The presence of the Treponema pallidum bacterium detrimentally affects the normal cytoarchitectural development of the soft, boney precursor tissues such as cartilage, giving rise to boney malformations like this “saddle nose” deformity.
Adapted from CDC

* This image depicts a lingual mucous patch on the tongue of a patient who was subsequently diagnosed with secondary syphilis, due to the Treponema pallidum bacterium. Secondary syphilis is the most contagious of all the stages of this disease, and is characterized by a systemic spread of the Treponema pallidum bacterial spirochetes. Skin rash and mucous membrane lesions characterize the secondary stage. The characteristic rash of secondary syphilis may appear as rough, red, or reddish brown spots both on the palms of the hands and the bottoms of the feet. However, rashes with a different appearance may occur on other parts of the body, sometimes resembling rashes caused by other diseases. Sometimes rashes associated with secondary syphilis are so faint that they are not noticed. In addition to rashes, symptoms of secondary syphilis may include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and fatigue. The signs and symptoms of secondary syphilis will resolve with or without treatment, but without treatment, the infection will progress to the latent and late stages of disease.
Adapted from CDC

* This patient presented demonstrating a rash on both arms due to secondary syphilis. Secondary syphilis is the most contagious of all the stages, and is characterized by the spread of the bacteria Treponema pallidum, which causes symptoms throughout the body.
Adapted from CDC

* This is an example of interstitial corneal keratitis in a patient with late congenital syphilis. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.
Adapted from CDC

* This newborn presented with symptoms of congenital syphilis that included lesions on the soles of both feet. If not treated immediately, an infected baby may be born without symptoms, but can develop them within a few weeks. These signs and symptoms can be very serious. Untreated babies may become developmentally delayed, have seizures, or die.
Adapted from CDC

* This patient presented with an extragenital syphilitic chancre of the left index finger. The chancre is usually firm, round, small, and painless, appearing at the spot where syphilis entered the body, and lasts 3-6 weeks, healing on its own. If adequate treatment is not administered, the infection progresses to the secondary stage.
Adapted from CDC

* This patient presented with secondary syphilytic lesions on the palms of her hands. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* These are secondary syphilitic lesions, known as syphilids on a patient's palms. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with secondary syphilytic lesions on the palms. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* These are secondary syphilitic lesions, known as syphilids on a patient's palms. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* A photograph depicts an anterior view of a patient's knees, who'd been diagnosed with "Clutton’s joints" due to what was determined to be congenital syphilis. See PHIL 12598, for a view of the patient's right knee, from a lateral perspective. ”Clutton's joints”, or symmetrical hydrarthrosis of the knee joints, is a painless condition that often occurs during the late stages of congenital syphilis. It involves synovitis, or swelling of a joint, accompanied by collections of fluid within the joint capsule.
Adapted from CDC

* This patient presented with a case of secondary syphilis manifested as perinal wart-like growths.
Adapted from CDC

* This patient with secondary syphilis manifested perineal condylomata lata lesions, which presented as gray, raised papules that sometimes appear on the vulva or near the anus, or in any other warm intertriginous region.
Adapted from CDC

* This patient presented with what was first thought to be syphilis, but turned out to be seborrheic dermatitis. This condition of the skin occurs in area of the body where the sebaceous glands experience an over-production of sebum, and subsequently gives rise to an infection and inflammation. Other causes include fungal involvement by a form of the yeast, Malassezia, having a genetic predisposition to this condition, hormonal changes disrupting the skin’s normal physiology, generalized stress, illness, fatigue, and sleep deprivation.
Adapted from CDC

* This patient presented with secondary papular syphilids on the soles of his feet. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This was a case of congenital syphilis resulting in the death of this newborn infant. Depending on how long a pregnant woman has been infected, she has a good chance of having a stillbirth, known as “syphilitic stillbirth”, or of giving birth to a baby who dies shortly after birth.
Adapted from CDC

* This patient presented with secondary syphilitic lesions on the plantar aspect of the foot. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with a papulosquamous rash of secondary syphilitic lesions on the plantar surface of his feet. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with secondary syphilitic lesions of the face. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* Note the keratotic secondary syphilitic lesions on the sole of this patient's right foot. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with secondary syphilitic lesions of the lips. Note the split papules at the angles of the mouth. Second-stage symptoms can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and tiredness. A person can easily pass the disease to sex partners during the primary or secondary stage of the disease.
Adapted from CDC

* This patient presented with secondary syphilitic lesions on the face. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with a primary syphilitic chancre of the lip. The primary stage of syphilis is usually marked by the appearance of a sore called a chancre. The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body, and lasts 3-6 weeks, healing on its own.
Adapted from CDC

* This patient presented with secondary annular syphilitic lesions of the face. Second-stage symptoms can include fever, swollen lymph glands, sore throat, patchy hair loss, headaches, weight loss, muscle aches, and tiredness. A person can easily pass the disease to sex partners during the primary or secondary stage of the disease.
Adapted from CDC

* This patient presented with areas of facial alopecia due to secondary syphilis. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with a primary syphilitic lesion of the right groin region. The primary stage of syphilis is usually marked by the appearance of a sore called a chancre. The chancre is usually firm, round, small, and painless. It appears at the spot where syphilis entered the body, and lasts 3-6 weeks, healing on its own.
Adapted from CDC

* These are psoriaform lesions on the legs of a patient with secondary syphilis. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own. Note the secondary palmar syphilytic lesions on this syphilis patient. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.
Adapted from CDC

* These keratotic lesions on the palms are due to secondary syphilis. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.
Adapted from CDC

* This patient presented with secondary syphilitic lesions on her face. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish-brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* The ulcerative primary syphilitic lesion on this patient's finger was due to lab acquired disease. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* This female patient presented with a case of granuloma inguinale with coexisting secondary syphilis. See PHIL 3485 and 18895, for additional views of this patient's condition. Granuloma inguinale, like syphilis, is also a sexually transmitted disease. It is a slowly progressive ulcerative condition of the skin and lymphatics of the genital, and perianal area caused by infection with Calymmatobacterium granulomatis.
Adapted from CDC

* This female patient presented with a case of granuloma inguinale with coexisting secondary syphilis. See PHIL 3486 and 18895, for additional views of this patient's condition. Granuloma inguinale, like syphilis, is also a sexually transmitted disease. It is a slowly progressive ulcerative condition of the skin and lymphatics of the genital, and perianal area caused by infection with Calymmatobacterium granulomatis.
Adapted from CDC

* This patient presented with a primary syphilitic chancre in the right inguinal region. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* This patient presented with a primary syphilitic chancre in the right inguinal region. The primary stage of syphilis is usually marked by the appearance of a single sore known as a chancre, but there may be multiple sores. The chancre is usually firm, round, small, and painless. These serpiginous, nodular ulcerative lesions are due to late syphilitic disease. The signs and symptoms of late stage syphilis include not being able to coordinate muscle movements, paralysis, numbness, gradual blindness and dementia. This damage may be serious enough to cause death.
Adapted from CDC

* This patient presented with a papulo-squamous rash on the sole of the foot due to secondary syphilis. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with a papular rash on the sole of the foot due to secondary syphilis. The second stage of syphilis starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of hands and on the bottoms of feet. Even without treatment, rashes clear up by itself.
Adapted from CDC

* This patient presented with phimosis and inguinal lymphadenopathy due to primary syphilis. One of the symptoms of primary syphilis is the presence of lymphadenopathy, i.e. the swelling of the inguinal lymph nodes, either bilaterally or unilaterally, as well as the presence of a primary chancre.
Adapted from CDC

* This patient presented with a secondary syphilitic maculopapular rash of the right hand and forearm. The second stage starts when one or more areas of the skin break into a rash that appears as rough, red or reddish brown spots both on the palms of the hands and on the bottoms of the feet. Even without treatment, rashes clear up on their own.
Adapted from CDC

* This patient presented with inguinal lymphadenopathy due to primary syphilis. One of the symptoms of primary syphilis is the presence of lymphadenopathy, i.e. the swelling of the inguinal lymph nodes, either bilaterally or unilaterally, as well as the presence of a primary chancre.
Adapted from CDC

* These were secondary syphilitic lesions on the palms of a 60 yr old woman. See PHIL 17051, for another image of this patient depicting a cutaneous labial lesion, which was also attributed to this illness. Syphilis is a complex sexually transmitted disease (STD) caused by the bacterium Treponema pallidum. It has often been called "the great imitator" because so many of the signs and symptoms are indistinguishable from those of other diseases.
Adapted from CDC

* Photograph of a patient with secondary syphilis presenting pigmented macules and papules on the skin. This patient has pigmented macules and papules of skin resulting from a cutaneous reaction during secondary syphilis, which is the most contagious of all the stages, and is characterized by the spread of the bacteria throughout the body.
Adapted from CDC

* Photograph of rhagades resulting from congenital syphilis. This patient with congenital syphilis is exhibiting rhagades, which are cracks or fissures in the skin around the mouth. Such a rare type of facial disfigurement, results from persistent infantile syphilitic rhinitis.
Adapted from CDC

* This photograph depicts a perforated hard palate on a patient with congenital syphilis. This patient with congenital syphilis has developed a perforation of hard palate due to gummatous destruction. These destructive tumors can also attack the skin, long bones, eyes, mucous membranes, throat, liver, or stomach lining.
Adapted from CDC

* This image depicts the dentition of a congenital syphilis patient, who due to this disease, went on to develop what are known as mulberry molars. “Moon's“, or mulberry molars, is a condition where the bite surface of the permanent first lower molar teeth develops rounded surfaces to its cusps, resembling the surface of a mulberry. Congenital syphilis, is a condition caused by infection in utero with Treponema pallidum. A wide spectrum of severity exists, and only severe cases are clinically apparent at birth. An infant or child (aged less than 2 years) may have signs such as hepatosplenomegaly, rash, condyloma lata, snuffles, jaundice (nonviral hepatitis), pseudoparalysis, anemia, or edema (nephrotic syndrome and/or malnutrition). An older child may have stigmata (e.g., interstitial keratitis, nerve deafness, anterior bowing of shins, frontal bossing, mulberry molars, Hutchinson teeth, saddle nose, rhagades, or Clutton joints).
Adapted from CDC

* A photograph of Hutchinson’s Teeth resulting from congenital syphilis. Hutchinson’s Teeth is a congenital anomaly in which the permanent incisor teeth are narrow and notched. Note the notched edges and "screwdriver" shape of the central incisors.
Adapted from CDC

* A photograph of a patient with congenital syphilis exhibiting interstitial corneal keratitis. This patient’s congenital syphilitic disease resulted in the onset of interstitial keratitis, an inflammation of the connective tissue structure of the cornea. Syphilis is the most common cause for this condition.
Adapted from CDC

* A photograph of a patient with tertiary syphilis resulting in gummas seen here on the nose. This patient presented with tertiary syphilitic gummas of the nose mimicking basal cell carcinoma. The gummatous tumors are benign and if properly treated, will heal and the patient will recover in most cases.
Adapted from CDC

* A photograph of a young child with congenital syphilis exhibiting intraoral mucous patches and facial skin lesions. An infant demonstrating mucous patches and skin lesions resulting from congenital syphilis. In 1998, 81.3% of reported cases of CS occurred because the mother received no penicillin treatment or inadequate treatment before or during pregnancy.
Adapted from CDC

* A photograph of a patient with tertiary syphilis resulting in gummatous lesions on the dorsal surface of the left hand. Gummatous lesions due to tertiary syphilis occur many years after initial untreated primary syphilis. The tumors are benign and if properly treated, the gummas will heal and the patient will recover in most cases.
Adapted from CDC

* A photograph of a patient with tertiary syphilis resulting in gummas seen here on the scalp. Tertiary syphilis occurs many years after initial untreated primary syphilis. Gummas, or internal tissue granulation, form and result in severe damage to the skin, bone, and liver.
Adapted from CDC

* A photograph of a patient with tertiary syphilis depicting gummatous lesions on the volar surface of the right arm. Tertiary syphilis occurs many years after initial untreated primary syphilis. Gummas, or internal tissue granulation, form and result in severe damage to the skin, bone, liver and other bodily organs, or regions.
Adapted from CDC

* The onset of this aortic aneurysm occurred during the tertiary stage of syphilis. This patient with late tertiary syphilis has developed an aortic aneurysm, which is eroding supraclavicularly through the ribs and clavicle. Cardiovascular syphilis can begin 5 to 10 years after initial infection.
Adapted from CDC

* Photograph of neuropathic arthropathy (Charcot joint) resulting from tertiary syphilis. This patient sustained progressive destruction, degeneration, and disorganization of the knee joint resulting from a loss of sensation caused by long standing tabes dorsalis. This condition was brought on during tertiary syphilis.
Adapted from CDC

* A photograph of mucous patches on the tongue due to secondary syphilis. Mucous patches form during the breakdown of mucous membranes, seen here on the inferior surface of the tongue. During the secondary stage of syphilis, mucous patches can also develop inside the mouth, vulva, and vagina.
Adapted from CDC

* A photograph of mucous patches on the lower lips due to secondary syphilis. Mucous patches form during the breakdown of mucous membranes, seen here on the inside the lower lip. During the secondary stage of syphilis, mucous patches can also develop inside the mouth, vulva, and vagina.
Adapted from CDC

* A photograph of syphilitic papules in the intertriginous areas of the toes. A patient with moist papules developing in the intertriginous areas between the toes. This clinical manifestation occurs during the secondary stage of syphilis, and is caused by the bacterium Treponema palladium.
Adapted from CDC

* A photograph of eyebrow alopecia, or hair loss, caused by secondary syphilis. This patient developed eyebrow alopecia during the secondary stage of syphilis. Other symptoms that may occur during this stage are mild fever, fatigue, headache, sore throat and swollen lymph glands.
Adapted from CDC

* A photograph of a patient with secondary syphilis showing typical "nickel and dime" lesions on the face. A patient with typical "nickel and dime" lesions on the face, which can develop during secondary syphilis. Other symptoms that may occur during this stage are mild fever, fatigue, headache, sore throat, patchy hair loss, and swollen lymph glands.
Adapted from CDC

* A patient with papulosquamous syphilids, or cutaneous eruptions of the disease, seen here on the wrist and palms. This patient presented with papulosquamous syphilids on the wrist and palms during the secondary stage of syphilis. The rash often appears as rough, red or reddish brown spots and can appear on both the palms of the hands and on the bottoms of the feet.
Adapted from CDC

* A photograph of secondary syphilitic lesions on the back and right shoulder. These papulosquamous lesions on the back and shoulder developed during secondary syphilis. The rash often appears as rough, red or reddish brown spots that can appear on palms of hands, soles of feet, the chest and back, or other parts of the body.
Adapted from CDC

* A photograph of secondary syphilitic lesions on a patient’s face. This patient with secondary syphilis has extensive lesions on the face. Secondary syphilis is the most contagious of all the stages, and is characterized by the spread of the bacteria Treponema pallidum, which causes symptoms throughout the body.
Adapted from CDC

* Photograph of secondary syphilitic papulosquamous lesions on penis, scrotum, and thighs. This patient with secondary syphilis has papulosquamous lesions of penis, scrotum, and thighs. Secondary syphilis is the most contagious of all the stages and is characterized by the spread of the bacteria which causes syphilis throughout the body.

* Photograph of secondary syphilitic papular rash on a patient’s left arm. A patient with a papular rash on the left arm that developed during secondary syphilis. The rash often appears as rough, red or reddish brown spots that can appear on palms of hands, soles of feet, the chest and back, or other parts of the body.
Adapted from CDC

* A photograph of a secondary syphilitic papulosquamous rash seen on the torso and upper body. This patient had an extensive papulosquamous rash that developed during secondary syphilis. The rash often appears as rough, red or reddish brown spots that can appear on palms of hands, soles of feet, the chest and back, or other parts of the body
Adapted from CDC

* A photograph of a primary syphilitic chancre of the lower lip due to Treponema pallidum bacteria. A patient with a typical syphilitic chancre located on lower lip. A chancre is a small, painless red ulcer that develops during primary syphilis. Primary syphilis is characterized by one or more chancres after inoculation with T. pallidum bacteria.
Adapted from CDC

* Photograph of a primary syphilitic penile meatal chancre caused by the bacterium Treponema pallidum. This patient has a primary syphilitic chancre located in the urethral meatus. A chancre is a primary skin lesion of syphilis which begins at the site of infection after an interval of 10-30 days as a papule or red ulcerated skin lesion.

* Patient with secondary syphilitic macular rash on the medial right foot. The rash often appears as rough, red or reddish brown spots, and can appear on both the palms of the hands as well as on the plantar surface (bottom) of the feet.
Adapted from CDC

* Chancres on the penile shaft due to a primary syphilitic infection caused by Treponema pallidum bacteria. The primary stage of syphilis is usually marked by the appearance of a single sore called a chancre. The chancre is usually firm, round, small, and painless.
Adapted from CDC

* A chancre of the posterior vaginal fourchette during the primary stage of syphilis. This chancre is located on the posterior vaginal fourchette (where labia minora meet). The primary stage of syphilis is often marked by the appearance of a single sore – called a chancre, which is usually firm, round, small, and painless.
Adapted from CDC

* A chancre on the penis due to primary syphilis. The primary stage of syphilis is usually marked by the appearance of a single sore called a chancre. The chancre is usually firm, round, small, and painless. This image shows a chancre located at the coronal sulcus of the penis.
Adapted from CDC

* * *

* * *

* Trichomoniasis `Return to Top`

* This photomicrograph of a wet-mounted vaginal discharge specimen, reveals numbers of Trichomonas vaginalis protozoan parasites, leading to a diagnosis of trichomoniasis, or “trich”, which is a very common sexually transmitted disease (STD) that is caused by infection with T. vaginalis. Although symptoms of the disease vary, most women and men who have the parasite cannot tell they are infected. The parasite is passed from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina, or urethra), and in men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite is usually transmitted from a penis to a vagina, or from a vagina to a penis, but it can also be passed from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not, but it probably depends on factors like the person’s age and overall health. Infected people without symptoms can still pass the infection on to others. Adapted from CDC

* This patient presented with a "strawberry cervix” due to a Trichomonas vaginalis infection, or trichomoniasis. The term “strawberry cervix” is used to describe the appearance of the cervix due to the presence of T. vaginalis protozoa. The cervical mucosa reveals punctate hemorrhages along with accompanying vesicles or papules.

* * *

### Parasite Gallery

### Parasite Gallery

#### A

* * *

* Acanthocephaliasis `Return to Top`

* * *

* Bolbosoma spp. `Return to Top`

* Transverse section through the body wall of Bolbosoma sp. in an intestinal biopsy specimen, stained with H&E. Image taken at 100x magnification. Cetaceans are the normal definitive hosts for Bolbosoma spp., and humans usually become infected after eating under-cooked fish which serve as paratenic hosts for the parasite.
Adapted from CDC

* Higher-magnification (200x) of the specimen in Figure 1. Identifiable in this image are the characteristic thin cuticle (CU, black arrow), syncytial epidermis (EP), longitudinal muscles (blue arrows) and eggs (green arrows).
Adapted from CDC

* Transverse section through the body wall of Bolbosoma sp. in an intestinal biopsy specimen, stained with H&E. Image taken at 100x magnification. In this image, a portion of the reproductive system is visible within the pseudocoelom.
Adapted from CDC

* * *

* Macracanthorhynchus hirudinaceous `Return to Top`

Eggs of M. hirudinaceous

* Eggs of M. hirudinaceous in an unstained wet mount of stool.
Adapted from CDC

* Egg of M. hirudinaceous in an unstained wet mount of stool.
Adapted from CDC

* Image of the same egg in Figure 2, but in a different plane of focus, showing the textured exterior.
Adapted from CDC

Adults of M. hirudinaceous

* Adult of M. hirudinaceous.
Adapted from CDC

* Higher magnification of the specimen in Figure 1, showing a close-up of the anterior end and the proboscis containing hooks.
Adapted from CDC

* Cross-section of the intestine of a pig, stained with H&E, showing the anterior end of an adult Macracanthorhynchus hirudinaceous embedded within the intestinal wall.
Adapted from CDC

* * *

* Moniliformis moniliformis `Return to Top`

Eggs of M. moniliformis

* Eggs of M. moniliformis liberated from an adult worm that was recovered from the stool of a patient.
Adapted from CDC

* Egg of M. moniliformis liberated from an adult worm that was recovered from the stool of a patient.
Adapted from CDC

Adults of M. moniliformis

* Adult of M. moniliformis.
Adapted from CDC

* Adult of M. moniliformis.
Adapted from CDC

* Higher magnification of the anterior end of the specimen in Figures 1 and 2, showing a close-up of the proboscis.
Adapted from CDC

* Higher magnification of the anterior end of the specimen in Figures 1 and 2, showing a close-up of the proboscis.
Adapted from CDC

* * *

* African trypanosomiasis (Sleeping sickness) `Return to Top`

* * *

* Trypansoma brucei `Return to Top`

Trypansoma brucei ssp. in thick blood smear stained with Giemsa

* Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
Adapted from CDC

* Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
Adapted from CDC

* Trypansoma brucei ssp. in a thick blood smear stained with Giemsa.
Adapted from CDC

Trypansoma brucei ssp. in thin blood smear stained with Giemsa

* Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa.
Adapted from CDC

Trypansoma brucei ssp. in thin blood smears stained with Wright-Giemsa

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

* Trypanosoma brucei ssp. in a thin blood smear stained with Wright-Giemsa.
Adapted from CDC

Trypansoma brucei ssp. in thin blood smear, beginning to divide

* Trypanosoma brucei ssp. in a thin blood smear stained with Giemsa. The trypomastigote is beginning to divide; dividing forms are seen in African trypanosomes, but not in American trypanosomes.
Adapted from CDC

* * *

* Amebiasis `Return to Top`

Amebiasis cysts

* Cyst of E. histolytica/E. dispar stained with trichrome. Note the chromatoid body with blunt ends (red arrow).

Amebiasis trophozioites

* Trophozoites of E. histolytic with ingested erythrocytes stained with trichrome. The ingested erythrocytes appear as dark inclusions. The parasite above show nuclei that have the typical small, centrally located karyosome, and thin, uniform peripheral chromatin.
Adapted from CDC

* Entamoeba histolytica trophozoites in colon tissue stained with H&E.
Adapted from CDC

* * *

* American trypanosomiasis (Chagas disease) `Return to Top`

* * *

* Trypanosoma cruzi `Return to Top`

Trypanosoma cruzi in thick blood smears stained with Giemsa

* Trypanosoma cruzi in thick blood smears stained with Giemsa.
Adapted from CDC

T. cruzi in thin blood smears stained with Giemsa

* T. cruzi trypomastigote in a thin blood smear stained with Giemsa. Note the typical C-shape of the trypomastigote that characterizes T. cruzi in fixed blood smears.
Adapted from CDC

* T. cruzi trypomastigote in a thin blood smear stained with Giemsa.
Adapted from CDC

* T. cruzi trypomastigote in a thin blood smear stained with Giemsa.
Adapted from CDC

* Higher magnification of Figure 3, T. cruzi.
Adapted from CDC

T. cruzi in cerebrospinal fluid (CSF) stained with Giemsa

* Trypanosoma cruzi trypomastigote in cerebrospinal fluid (CSF) stained with Giemsa.
Adapted from CDC

T. cruzi amastigotes in heart tissue

* Trypanosoma cruzi amastigotes in heart tissue. The section is stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Trypanosoma cruzi amastigotes in heart tissue. The section is stained with H&E.
Adapted from CDC

T. cruzi epimastigotes, from culture

* Trypanosoma cruzi epimastigotes from culture. Note the location of the kinetoplast anterior to the nucleus.
Adapted from CDC

* * *

* Ancylostomiasis (Hookworm) `Return to Top`

* * *

* Ancylostoma braziliense `Return to Top`

* * *

* Ancylostoma caninum `Return to Top`

* Anterior end of an adult of Ancylostoma caninum, a dog parasite that has been found to produce a rare human infection known as eosinophilic enteritis.
Adapted from CDC

* * *

* Ancylostoma ceylanicum `Return to Top`

* * *

* Ancylostoma duodenale `Return to Top`

* Adult worm of Ancylostoma duodenal. Anterior end is depicted showing cutting teeth.
Adapted from CDC

* * *

* Necator americanus `Return to Top`

* Adult worm of Necator americanus. Anterior end showing mouth parts with cutting plates.
Adapted from CDC

* * *

* Angiostrongyliasis `Return to Top`

* * *

* Angiostrongylus cantonensis `Return to Top`

* Angiostrongylus cantonensis third stage (L3), infective larva recovered from a slug. Image captured under differential interference contrast (DIC) microscopy.
Adapted from CDC

* A. cantonensis (L3), infective larvae recovered from a slug. Image captured under DIC microscopy.
Adapted from CDC

* Higher magnification of Image 2. Note the terminal projection on the tip of the tail which is characteristic of A. cantonensis.
Adapted from CDC

* Angiostrongylus cantonensis third stage (L3), infective larva, in a wet mount, recovered from a slug. Note the terminal projection on the tip of the tail which is characteristic of A. cantonensis.
Adapted from CDC

* A. cantonensis L3, infective larvae, in wet mounts, recovered from slugs.
Adapted from CDC

* A. cantonensis L3, infective larvae, in wet mounts, recovered from slugs.
Adapted from CDC

* * *

* Angiostrongylus costaricensis `Return to Top`

A. costaricensis Eggs

* Angiostrongylus costaricensis eggs in intestinal tissue stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Thin-shelled A. costaricensis eggs in intestinal tissue stained with H&E, a feature consistent with the presence of mature female worms.
Adapted from CDC

* A. costaricensis first stage (L1) larva in intestinal tissue stained with H&E
Adapted from CDC

A. costaricensis adult female in tissue sections stained with H&E

* Angiostrongylus costaricensis female worm in appendix tissue sections stained with hematoxylin and eosin (H&E). Image courtesy of Regions Hospital, St. Paul, MN.
Adapted from CDC

* Higher magnification of the specimen in Figure 1. Notice the thick, multinucleate intestine (IN) and eggs (EG) within the uterus (UT).
Adapted from CDC

* Another image from the specimen seen in Figure 1.
Adapted from CDC

* Higher magnification of the specimen in Figure 3. Shown here are the thick, multinucleate intestine (IN), reproductive tubes (RT), and lateral chords (LC).
Adapted from CDC

* * *

* Anisakiasis `Return to Top`

* * *

* Anisakis simplex `Return to Top`

* Cross-section of Anisakis sp., viewed under DIC microscopy.
Adapted from CDC

* Higher magnification of the specimen in Figure 1. Note the tall, prominent muscle cells (MU) and Y-shaped lateral chords (LC), characteristic for this genus.
Adapted from CDC

* * *

* Pseudoterranova decipiens `Return to Top`

Pseudoterranova sp. larval worms

* Anterior ends of Pseudoterranova sp. worms; images taken at 40x and 200x magnification, respectively.
Adapted from CDC

* Anterior ends of Pseudoterranova sp. worms; images taken at 40x and 200x magnification, respectively.
Adapted from CDC

* Anterior end of Pseudoterranova sp. The red arrow indicates the intestinal cecum.
Adapted from CDC

* Close-up of the intestinal cecum in the same specimen seen in Figure 3.
Adapted from CDC

* Mid-section of a Pseudoterranova sp. worm, showing the esophagus and intestine. Image taken at 40x magnification.
Adapted from CDC

* Posterior end of Pseudoterranova sp. Image taken at 200x magnification.
Adapted from CDC

Cross sections of Pseudoterranova sp. worms Cross sections of anisakid worms.

* Cross-section of Pseudoterranova sp. Note the large butterfly-shaped lateral chords (black arrows), characteristic for this genus.
Adapted from CDC

* Cross-section of Pseudoterranova sp. viewed under differential interference contrast (DIC) microscopy.
Adapted from CDC

* * *

* Ascariasis `Return to Top`

* * *

* Ascaris lumbricoides `Return to Top`

Adult A. lumbricoides

* Adult female A. lumbricoides.
Adapted from CDC

Unfertilized egg of A. lumbricoides

* Unfertilized egg of A. lumbricoides in an unstained wet mount, 200x magnification.
Adapted from CDC

Fertilized egg of A. lumbricoides

* Fertilized egg of A. lumbricoides in unstained wet mounts of stool, with embryos in the early stage of development.
Adapted from CDC

A. lumbricoides in tissue specimen

* Eggs of A. lumbricoides in an appendix biopsy, stained with H&E. This image was taken at 200x magnification.
Adapted from CDC

#### B

* * *

* Babesiosis `Return to Top`

* * *

* Babesia divergens `Return to Top`

* * *

* Babesia microti `Return to Top`

* Babesia microti in a thin blood smear stained with Giemsa. Babesia sp. cannot be identified to the species level by morphology alone; additional testing, such as PCR, is always recommended.
Adapted from CDC

* Babesia microti in a thin blood smear stained with Giemsa. Babesia sp. cannot be identified to the species level by morphology alone; additional testing, such as PCR, is always recommended. Note the tetrad form in this image.
Adapted from CDC

* Babesia microti in a thin blood smear stained with Giemsa. Note the intra-erythrocytic vacuolated forms indicated by the black arrows.
Adapted from CDC

* * *

* Balantidiasis `Return to Top`

* * *

* Balantidium coli `Return to Top`

B. coli cysts

* B. coli cysts in a wet mount, unstained.
Adapted from CDC

B. coli trophozoites

* B. coli trophozoite in a wet mount, 500× magnification. Note the visible cilia on the cell surface.
Adapted from CDC

* Balantidium coli trophozoites in colon tissue stained with hematoxylin and eosin (H&E) at 400x magnification.
Adapted from CDC

* * *

* Baylisascariasis `Return to Top`

* * *

* Baylisascaris procyonis `Return to Top`

Baylisascaris procyonis eggs

* Unembryonated egg of B. procyonis.
Adapted from CDC

* Embryonated eggs of B. procyonis, showing the developing larva inside.
Adapted from CDC

Baylisascaris procyonis larvae

* Larva of B. procyonis hatching from an egg.
Adapted from CDC

* Cross-sections of larvae of B. columnaris in muscle of a laboratory-infected mouse. The larval morphology and microscopic manifestations would be similar with B. procyonis in human tissue. Image taken at 400x magnification.
Adapted from CDC

Baylisascaris procyonis larvae

* Larva of B. procyonis hatching from an egg.
Adapted from CDC

* Cross-sections of larvae of B. columnaris in muscle of a laboratory-infected mouse. The larval morphology and microscopic manifestations would be similar with B. procyonis in human tissue. Image taken at 400x magnification.
Adapted from CDC

* * *

* Bed Bugs `Return to Top`

* * *

* Cimex hemipterus `Return to Top`

* * *

* Cimex lectularius `Return to Top`

* Two adults and one nymph (arrow) of C. lectularius, collected in a hotel in urban Georgia.
Adapted from CDC

* Close-up of one of the adults in Figure 1.
Adapted from CDC

* Higher magnification of the specimen in Figure 2. Note the reduced forewings (arrow).
Adapted from CDC

* Ventral view of the specimen in Figure 2.
Adapted from CDC

* Higher magnification of the specimen in Figure 4, showing a close-up of the typical hemipteran piercing-sucking mouthparts (arrow).
Adapted from CDC

* Nymph of C. lectularius. The blue marks represent 1 mm.
Adapted from CDC

* * *

* Bertiella infection `Return to Top`

* Eggs of Bertiella sp. liberated from proglottids. The proglottids were shed from a human patient who had lived for a number of years in Africa. In several of these eggs, the pyriform apparatus can be easily seen. Images courtesy of Clinipath Pathology, Perth, Australia.
Adapted from CDC

* An egg of Bertiella sp. liberated from a gravid proglottid. The arrows point to the hooklets.
Adapted from CDC

* Proglottids of Bertiella sp.
Adapted from CDC

* * *

* Bertiella mucronata `Return to Top`

* * *

* Bertiella struderi `Return to Top`

* Scolex of Bertiella studeri. Image courtesy of Richard Bradbury.
Adapted from CDC

* * *

* Blastocystis hominis infection `Return to Top`

* * *

* Blastocystis hominis `Return to Top`

Blastocystis hominis cyst-like forms in wet mounts

* B. hominis cyst-like forms in a wet mount, unstained.
Adapted from CDC

* B. hominis cyst-like form in a wet mount, unstained.
Adapted from CDC

B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy

* B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy.
Adapted from CDC

* B. hominis cyst-like forms in wet mounts under differential interference contrast (DIC) microscopy.
Adapted from CDC

B. hominis cyst-like forms in wet mounts stained with iodine

* B. hominis cyst-like forms in wet mounts stained in iodine.
Adapted from CDC

* B. hominis cyst-like forms in wet mounts stained in iodine.
Adapted from CDC

B. hominis cyst-like forms stained with trichrome

* B. hominis cyst-like forms stained with trichrome. The nuclei in the peripheral cytoplasmic rim are visible, staining purple.
Adapted from CDC

* B. hominis cyst-like forms stained with trichrome. The nuclei in the peripheral cytoplasmic rim are visible, staining purple.
Adapted from CDC

* Blastocystis hominis cyst-like forms stained with trichrome.
Adapted from CDC

* Blastocystis hominis cyst-like forms stained with trichrome.
Adapted from CDC

* B. hominis cyst-like forms stained with trichrome.
Adapted from CDC

* B. hominis cyst-like forms undergoing binary fission; stained with trichrome.
Adapted from CDC

* B. hominis cyst-like forms stained with trichrome.
Adapted from CDC

#### C

* * *

* Cercarial dermatitis (Swimmer’s itch) `Return to Top`

* * *

* Austrobilharzia variglandis `Return to Top`

Cercaria of Austrobilharzia variglandis

* Cercaria of Austrobilharzia variglandis, which can cause cercarial dermatitis.
Adapted from CDC

* Cercaria of Austrobilharzia variglandis, which can cause cercarial dermatitis. Note the forked 'tail' and a pair of 'eye spots' near the anterior end.
Adapted from CDC

Clinical manifestations of Austrobilharzia variglandis

* Skin of a patient showing the inflammatory response to cercaria in the skin.
Adapted from CDC

* * *

* Chilomastix mesnili `Return to Top`

Chilomastix mesnili trophozoites, trichrome stain

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Trophozoite of C. mesnili from a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

Chilomastix mesnili cysts, trichrome stain

* Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Cyst of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

* Cyst (lower) and trophozoite (upper) of C. mesnili in a stool specimen, stained with trichrome. Image taken at 1000x magnification.
Adapted from CDC

Chilomastix mesnili cysts in wet mounts

* Cyst of C. mesnili in a concentrated wet mount of stool, stained with iodine. Image taken at 1000x magnification.
Adapted from CDC

* Cyst of C. mesnili in a concentrated wet mount of stool, stained with iodine. Image taken at 1000x magnification.
Adapted from CDC

* * *

* Clonorchiasis `Return to Top`

* * *

* Clonorchis sinensis `Return to Top`

Clonorchis sinensis eggs

* C. sinensis egg: the small knob at the abopercular end is visible in this image.
Adapted from CDC

* C. sinensis egg. Note the operculum resting on "shoulders;" image taken at 400× magnification.
Adapted from CDC

* C. sinensis egg; images taken at 400× magnification.
Adapted from CDC

* C. sinensis egg; images taken at 400× magnification.
Adapted from CDC

Clonorchis sinensis adults

* Adult of C. sinensis.
Adapted from CDC

* Adult of C. sinensis stained with carmine. Clearly visible in this image are the oral sucker (OS), pharynx (PH), ceca (CE), acetabulum, or ventral sucker (AC), uterus (UT), vitellaria (VT) and testes (TE).
Adapted from CDC

Clonorchis sinensis eggs

* Shells of Parafossarulus manchouricus, the most common snail host of C. sinensis in endemic areas in southeast Asia. Image courtesy of the Web Atlas of Medical Parasitology and the Korean Society for Parasitology.
Adapted from CDC

* Bithynia sp., another common intermediate host of C. sinensis. Image courtesy of Michal Maňas.
Adapted from CDC

* * *

* Coenurosis `Return to Top`

* * *

* Taenia spp. `Return to Top`

Gross coenurus specimens

* Large, polycephalic coenurus removed from the shoulder of a baboon (Papio sp.).
Adapted from CDC

* Close-up of a coenurus of T. multiceps removed from the eye of a patient, broken open to show multiple protoscoleces.
Adapted from CDC

Coenuri in tissue specimens, stained with hematoxylin and eosin (H&E)

* Coenurus removed from a subcutaneous nodule in the shoulder area of a patient, stained with hematoxylin and eosin (H&E). Image taken at 50x magnification. Although the species was not identified in this case, the pathology is consistent with T. serialis.
Adapted from CDC

* Higher magnification (200x) of the coenurus in Figure 1.
Adapted from CDC

* Higher magnification (200x) of the same specimen shown in Figures 1 and 2. The black arrows point to hooklets in the protoscoleces.
Adapted from CDC

* Higher magnification (200x) of the same specimen shown in Figures 1 and 2. The black arrows point to hooklets in the protoscoleces.
Adapted from CDC

Coenurus in an eye specimens, stained with hematoxylin and eosin (H&E)

* Cross-section of a human eye, showing multiple protoscoleces within a coenurus.
Adapted from CDC

* Higher magnification (200x) of the coenurus in Figure 1.
Adapted from CDC

* Higher magnification (200x) of protoscoleces shown in Figures 1 and 2.
Adapted from CDC

* Higher magnification (200x) of protoscoleces shown in Figures 1 and 2.
Adapted from CDC

* Higher magnification of the protoscolex in Figure 4, showing multiple hooklets.
Adapted from CDC

* * *

* Cryptosporidiosis `Return to Top`

* * *

* Cryptosporidium spp. `Return to Top`

Cryptosporidium sp. oocysts in a wet mount

* Cryptosporidium spp. oocysts (pink arrows) in wet mount. A budding yeast (brown arrow) is in the same field.
Adapted from CDC

* Cryptosporidium parvumoocysts in wet mount, under differential interference contrast (DIC) microscopy. The oocysts are rounded and measure 4.2 µm - 5.4 µm in diameter. Sporozoites are visible inside the oocysts, indicating that sporulation has occurred.
Adapted from CDC

Cryptosporidium sp. oocysts stained with trichrome

* Cryptosporidium sp. oocysts stained with trichrome. Oocysts may be detected, but should not be confirmed by this method. Trichrome staining is inadequate for a definite diagnosis because oocysts will appear unstained. Here the Cryptosporidium oocysts are represented by red arrows; the blue arrow represents yeast.
Adapted from CDC

* Cryptosporidium sp. oocyst stained with trichrome. Oocysts may be detected, but should not be confirmed by this method. Trichrome staining is inadequate for a definite diagnosis because oocysts will appear unstained. Here the Cryptosporidium oocyst is represented by a red arrow; the blue arrows represent yeast.
Adapted from CDC

Cryptosporidium sp. oocysts stained with modified acid-fast

* Cryptosporidium parvum oocysts stained with modified acid-fast. Against a blue-green background, the oocysts stand out in a bright red stain. Sporozoites are visible inside the two oocysts to the right in this image.
Adapted from CDC

* Cryptosporidium parvum oocysts stained with modified acid-fast. Against a blue-green background, the oocysts stand out in a bright red stain.
Adapted from CDC

* Cryptosporidium sp. oocysts stained with modified acid-fast.
Adapted from CDC

* Cryptosporidium sp. oocyst stained with modified acid-fast.
Adapted from CDC

Cryptosporidium sp. oocysts unstained on a slide stained with modified acid-fast

* Cryptosporidium sp. oocysts (red arrows) that did not take up the modified acid-fast stain. The slide was counterstained with methylene blue. Note that yeast cells did stain red (yellow arrows).
Adapted from CDC

* Unstained Cryptosporidium sp. oocysts (black arrows) on a slide stained with modified acid-fast. The slide was counterstained with malachite green.
Adapted from CDC

Cryptosporidium sp. oocysts stained with safranin

* Cryptosporidium sp. oocysts stained with safranin.
Adapted from CDC

* Cryptosporidium sp. oocysts stained with safranin.
Adapted from CDC

Cryptosporidium sp. oocysts stained with Ziehl-Neelsen modified acid-fast

* Cryptosporidium sp. oocysts stained with Ziehl-Neelson modified acid-fast. Image contributed by the Oregon State Public Health Laboratory.
Adapted from CDC

Cryptosporidium parvum oocysts stained with the fluorescent stain auramine-rhodamine

* Cryptosporidium parvum oocysts stained with the fluorescent stain auramine-rhodamine.
Adapted from CDC

Oocysts of C. parvum' and cysts of Giardia duodenalis labeled with immunofluorescent antibodies

* Cryptosporidium sp. oocysts labeled with immunofluorescent antibodies. Images contributed by the Kansas Department of Health and Environment.
Adapted from CDC

* Cryptosporidium sp. oocyst labeled with immunofluorescent antibodies. Images contributed by the Kansas Department of Health and Environment.
Adapted from CDC

* Cryptosporidium sp. oocysts (yellow arrows) and cysts of Giardia duodenalis (red arrow) labeled with immunofluorescent antibodies.
Adapted from CDC

* Cryptosporidium sp. oocysts (yellow arrows) and cysts of Giardia duodenalis (red arrows) labeled with immunofluorescent antibodies.
Adapted from CDC

* * *

* Cyclosporiasis `Return to Top`

* * *

* Cyclospora cayetanensis `Return to Top`

Cyclospora cayetanensis oocysts in wet mounts

* Oocyst of C. cayetanensis in an unstained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Oocyst of C. cayetanensis in an unstained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Oocyst of C. cayetanensis in an unstained wet mount of stool. Image taken at 1000x magnification.
Adapted from CDC

* Oocyst of C. cayetanensis in an unstained wet mount of stool. Image taken at 1000x magnification.
Adapted from CDC

Cyclospora cayetanensis oocysts stained with trichrome

* Oocyst of C. cayetanensis stained with trichrome; while the oocyst is visible, the staining characteristics are inadequate for a reliable diagnosis.
Adapted from CDC

* Oocysts of C. cayetanensis stained with trichrome; while the oocyst is visible, the staining characteristics are inadequate for a reliable diagnosis.
Adapted from CDC

C. cayetanensis oocysts viewed under ultraviolet (UV) microscopy

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under UV microscopy.
Adapted from CDC

C. cayetanensis oocysts stained with modified acid-fast

* Oocysts of C. cayetanensis stained with modified acid-fast stain. Note the variability of staining in the four oocysts.
Adapted from CDC

* Two oocysts of C. cayetanensis stained with modified acid-fast stain. Both oocysts failed to take up the carbol fuschin stain. Image courtesy of the Arizona State Public Health Laboratory.
Adapted from CDC

* Oocysts of C. cayetanensis stained with modified acid-fast stain. Note the wrinkled edge and the lack of stain in the two oocysts. Image courtesy of the Arizona State Public Health Laboratory.
Adapted from CDC

* Oocyst of C. cayetanensis stained with modified acid-fast stain.
Adapted from CDC

* Oocysts of C. cayetanensis stained with modified acid-fast stain.
Adapted from CDC

* Oocysts of C. cayetanensis stained with modified acid-fast stain.
Adapted from CDC

C. cayetanensis oocysts stained with safranin (SAF)

* Oocyst of C. cayetanensis stained with safranin (SAF).
Adapted from CDC

* Oocyst of C. cayetanensis stained with safranin (SAF).
Adapted from CDC

* Oocyst of C. cayetanensis stained with safranin (SAF).
Adapted from CDC

* Oocyst of C. cayetanensis stained with safranin (SAF).
Adapted from CDC

* A pair of oocysts of C. cayetanensis stained with safranin (SAF).
Adapted from CDC

* Oocyst of C. cayetanensis (yellow arrow) along with an oocyst of Cryptosporidium parvum (red arrow), stained with safranin (SAF). Cryptosporidium spp. also stain with the safranin and modified acid-fast stains.
Adapted from CDC

C. cayetanensis oocysts viewed under differential interference contrast (DIC) microscopy

* Oocyst of C. cayetanensis viewed under differential interference contrast (DIC) microscopy. The refractile globules are easily visible under DIC.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under differential interference contrast (DIC) microscopy. The refractile globules are easily visible under DIC.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under DIC microscopy. There are two sporocysts are visible in this image.
Adapted from CDC

* Oocyst of C. cayetanensis viewed under DIC microscopy.
Adapted from CDC

* A pair of oocysts of C. cayetanensis viewed under DIC microscopy.
Adapted from CDC

* Rupturing oocyst of C. cayetanensis viewed under DIC microscopy. One sporocyst has has been released from the mature oocyst; the second sporocyst is still contained within the oocyst wall.
Adapted from CDC

* * *

* Cysticercosis `Return to Top`

* * *

* Taenia solium `Return to Top`

Larval Taenia solium

* Larval Taenia solium cyst in a section of a lesion found in the right frontal lobe of a patient stained with hematoxylin and eosin (H&E), magnification 40×.
Adapted from CDC

* An entire cysticercus seen within the bladder walls (blue arrows). A single scolex is visible inside yellow circle) within the cyst.
Adapted from CDC

* Higher magnification (100×) of the cyst in Figures 1 and 2. The parenchymatous portion of the cysticercus can be better observed.
Adapted from CDC

* The extensive folding of the spiral canal and one sucker of the scolex (black arrow) are apparent. Calcareous corpuscles can be seen in the fibrous tissues (green arrows).
Adapted from CDC

* Cross-sections of cysticerci stained with H&E, at 40x magnification
Adapted from CDC

* Cross-sections of cysticerci stained with H&E, at 100x magnification.
Adapted from CDC

* * *

* Cystoisosporiasis (Isosporiasis) `Return to Top`

* * *

* Cystoisospora belli (Isospora belli) `Return to Top`

Cystoisospora belli oocysts

* Immature oocyst of C. belli in an unstained wet mount, containing a single sporoblast.
Adapted from CDC

* Immature oocyst of C. belli stained with safranin, containing a single sporoblast.
Adapted from CDC

* Immature oocyst of C. belli stained with acid-fast, showing a single sporoblast.
Adapted from CDC

* Oocyst of C. belli viewed under ultraviolet (UV) microscopy, showing two sporoblasts.
Adapted from CDC

* Immature oocyst of C. belli in an unstained wet mount showing a single sporoblast.
Adapted from CDC

* Immature oocyst of C. belli in an unstained wet mount showing two sporoblasts.
Adapted from CDC

* Same oocyst as in Figure 1 but viewed under differential interference contrast (DIC)
Adapted from CDC

* Same oocyst as in Figure 2 but viewed under ultraviolet (UV) fluorescent micrscopy.
Adapted from CDC

* Same oocyst as in Figures 1 and 3 but viewed under ultraviolet (UV) fluorescent micrscopy.
Adapted from CDC

* Same oocyst as in Figures 2 and 4 but viewed under UV microscopy.
Adapted from CDC

Cystoisospora belli oocysts, stained with hematoxylin and eoisin (H&E)

* Oocyst of C. belli in the epithelial cells of a mammalian host, stained with H&E (yellow arrow).
Adapted from CDC

* Oocyst of C. belli in the epithelial cells of a mammalian host, stained with H&E (yellow arrow).
Adapted from CDC

#### D

* * *

* Dicrocoeliasis `Return to Top`

* * *

* Dicrocoelium dendriticum `Return to Top`

Dicrocoelium dendriticum eggs in wet mounts

* Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
Adapted from CDC

* Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
Adapted from CDC

* Egg of Dicrocoelium dendriticum in an unstained wet mount of stool. Image courtesy of Dr. Juan Cuadros González.
Adapted from CDC

* Egg of D. dendriticum in an unstained wet mount of stool.
Adapted from CDC

* Egg of D. dendriticum in an unstained wet mount of stool.
Adapted from CDC

Dicrocoelium dendriticum adults

* Adult of D. dendriticum, stained with carmine. Structures illustrated in this figure include: oral sucker (OS), acetabulum (AC), uterus (UT), testes (TE), and vitelline glands (VT).
Adapted from CDC

Intermediate hosts of Dicrocoelium dendriticum

* Zebrina detrita, a common first intermediate host for D. dendriticum. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Formica fusca, a common second intermediate host for D. dendriticum in Europe. Image courtesy of Sedeer El-Showk.
Adapted from CDC

* * *

* Dientamoeba fragilis infection `Return to Top`

* * *

* Dientamoeba fragilis `Return to Top`

Dientamoeba fragilis binucleate trophozoites stained with trichrome

* Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate form of trophozoites of D. fragilis, stained with trichrome. A cyst-like form of Blastocystis hominis lies to the left of the D. fragilis.
Adapted from CDC

Dientamoeba fragilis uninucleate trophozoites stained with trichrome

* Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Uninucleate form of a trophozoite of D. fragilis, stained with trichrome.
Adapted from CDC

* Binucleate and uninucleate forms of trophozoites of D. fragilis, stained with trichrome.
Adapted from CDC

* * *

* Dioctophymiasis `Return to Top`

* * *

* Dioctophyme renale `Return to Top`

Larvae of Dioctotphyme renale in human tissue

* Cross-sections of larvae of D. renal in a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Images courtesy of the Laboratory of Parasitology, National Public Health Research Center in Vilnius, Lithuania.
Adapted from CDC

* Cross-sections of larvae of D. renal in a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Images courtesy of the Laboratory of Parasitology, National Public Health Research Center in Vilnius, Lithuania
Adapted from CDC

* Higher-magnification of the specimens shown in Figures 1 and 2, showing a close-up of the characteristic intestine, with cuboidal, uninucleate cells, pigment, and microvilli.
Adapted from CDC

* Higher-magnification of the specimens shown in Figures 1 and 2, showing a close-up of the characteristic intestine, with cuboidal, uninucleate cells, pigment, and microvilli.
Adapted from CDC

* Higher-magnification of the specimens shown in Figures 1-4. Shown in this image are the tall, polymyarian muscle cells, the characteristic ventral chord with a U-shaped row of nuclei (black arrow), and three pseudocoelomic membranes (red arrows).
Adapted from CDC

* Close-up of Figure 1, showing the ventral chord (black-arrow).
Adapted from CDC

Eggs of D. renale in animal tissue

* Egg of D. renale in the kidney of a mink, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Egg of D. renale in the kidney of a mink, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* * *

* Diphyllobothriasis `Return to Top`

* * *

* Diphyllobothrium latum `Return to Top`

Diphyllobothrium latum eggs in wet mounts

* Eggs of D. latum in an iodine-stained wet mount. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Note the knob at the abopercular end. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Eggs of D. latum within a proglottid. Image courtesy of the Florida State Public Health Laboratory.
Adapted from CDC

* Eggs of D. latum within a proglottid.
Adapted from CDC

* Eggs of D. latum in an unstained wet mount.
Adapted from CDC

* Eggs of D. latum in an unstained wet mount of stool. Note the opercula are open.
Adapted from CDC

Eggs of Diphyllobothrium latum eggs in wet mounts

* Egg of D. latum in an unstained wet-mount of stool.
Adapted from CDC

Proglottids of Diphyllobothrium latum

* Section of an adult D. latum containing many proglottids. The scolex was not present in this specimen. Image courtesy of the Florida State Public Health Laboratory.
Adapted from CDC

* Close-up of a few of the proglottids from the specimen in Figure 1, showing the rosette-shaped uterus at the center of each proglottid.
Adapted from CDC

* Carmine-stained proglottids of D. latum, showing the rosette-shaped ovaries.
Adapted from CDC

* Carmine-stained proglottids of D. latum, showing the rosette-shaped ovaries.
Adapted from CDC

* Scolex of D. latum.
Adapted from CDC

* * *

* Dipylidium caninum infection `Return to Top`

Dipylidium caninum egg packets in wet mounts

* D. caninum egg packet, containing 8 visible eggs, in a wet mount.
Adapted from CDC

* D. caninum egg packet in a wet mount.
Adapted from CDC

* D. caninum egg packet in wet mount.
Adapted from CDC

* D. caninum egg packet in wet mount.
Adapted from CDC

* D. caninum egg packet in wet mount.
Adapted from CDC

D. caninum eggs in wet mounts under conventional and differential interference contrast microscopy

* D. caninum eggs clumped together in a wet mount. Image taken at 200x magnification.
Adapted from CDC

* D. caninum eggs clumped together in a wet mount. Image taken at 400x magnification, hooklets in the some of the eggs are visible.
Adapted from CDC

* D. caninum eggs clumped together under differential interference contrast microscopy (same eggs as in Figure 2).
Adapted from CDC

* Close up of Figure 3. Note the visible hooklets in three of the eggs.
Adapted from CDC

D. caninum proglottids

* D. caninum proglottid under a dissecting microscope cleared with lactophenol.
Adapted from CDC

* D. caninum proglottid.
Adapted from CDC

* D. caninum proglottid partially cleared with lactophenol, showing eggs and egg packets.
Adapted from CDC

* D. caninum proglottid. The genital pores are clearly visible in the carmine-stained proglottid.
Adapted from CDC

Cross-section of a D. caninum proglottid stained with hematoxylin and eosin (H&E)

* Cross-section of a D. caninum proglottid stained with H&E. Image taken at 100x magnification.
Adapted from CDC

* Cross-section of a D. caninum proglottid stained with H&E. Image taken at 200x magnfication.
Adapted from CDC

* Cross-section of a D. caninum proglottid stained with H&E. Image taken at 400x magnification
Adapted from CDC

* Cross-section of a D. caninum proglottid stained with H&E. Image taken at 1000x magnification.
Adapted from CDC

D. caninum scolex

* D. caninum scolex.
Adapted from CDC

Adult tapeworm of D. caninum

* Adult tapeworm of D. caninum. The scolex of the worm is very narrow and the proglottids, as they mature, get larger.
Adapted from CDC

* * *

* Dirofilariasis `Return to Top`

* * *

* Dirofilaria sp. `Return to Top`

* Cross-section of Dirofilaria sp. from a subcutaneous nodule, stained with hematoxylin and eosin (H&E). Morphologic features visible in this image include tall, prominent muscle cells (MU), coiled vagina (VG), coiled intestine (IN), lateral chords (LC), and prominent internal lateral ridges (IR). Image courtesy of Drs. Dirk Elston and Paul Bourbeau.
Adapted from CDC

* Cross-sections of Dirofilaria spp. from a subcutaneous scalp nodule, stained with H&E. Image courtesy of the Department of Dermatopathology, University of Michigan, Ann Arbor, MI.
Adapted from CDC

* Cross-sections of Dirofilaria sp. from a subcutaneous nodule above the right breast of a female patient who traveled to several western European countries, stained with H&E. Image taken at 100x magnification. Image courtesy of Dr. Truus Derks.
Adapted from CDC

* Higher magnification of the same specimen as Figure 3, taken at 400x magnification. Note the presence of lateral chords (blue arrows) and internal lateral ridge (black arrow).
Adapted from CDC

* Dirofilaria sp. (suspect D. tennis) removed from the eye of a patient.
Adapted from CDC

* Close-up of the specimen in Figure 5 showing the cuticular ridging. A uterine tube can also be seen through the cuticle.
Adapted from CDC

* * *

* Dracunculiasis (Guinea Worm Disease) `Return to Top`

* * *

* Drancunculus medinensis `Return to Top`

A female Dracuncunculus medinensis in a human host

* The female Guinea worm induces a painful blister.
Adapted from CDC

* After rupture of the blister, the worm emerges as a whitish filament in the center of a painful ulcer which is often secondarily infected. (Images contributed by Global 2000/The Carter Center, Atlanta, Georgia).
Adapted from CDC

#### E

* * *

* Echinococcosis (Hydatid disease) `Return to Top`

* * *

* Echinococcus granulosus `Return to Top`

Echinococcus granulosus in tissue

* Protoscoleces in a hydatid cyst removed from lung tissue, stained with hematoxylin and eosin (H&E). Image taken at 200x magnification. Image courtesy of Phoenix Children's Hospital, Phoenix, AZ.
Adapted from CDC

* Higher magnification (600x) of the protoscoleces in Figure 1.
Adapted from CDC

* Cross-section of an E. granulosus cyst, stained with H&E. The cyst wall is composed of an acellular laminated external layer (green arrow) and a thin, germinal (nucleated) inner layer (yellow arrow). Note the brood capsule (black arrow) with protoscoleces (blue arrows) inside. Image taken at 40x magnification.
Adapted from CDC

* Higher magnification (200x) of the cyst in Figure 3, showing daughter cyst (brood capsule). Note the hooklets (purple arrow) inside one of the protoscoleces and the calcareous corpuscles (light blue arrows) along the germinal layer.
Adapted from CDC

* Protoscoleces liberated from a hydatid cyst.
Adapted from CDC

* Protoscoleces liberated from a hydatid cyst.
Adapted from CDC

Echinococcus granulosus adults

* Echinococcus granulosus adult, stained with carmine.
Adapted from CDC

* Close-up of the scolex of E. granulosus in Figure 1. In this focal plane, one of the suckers is clearly visible, as is the ring of rostellar hooks.
Adapted from CDC

* * *

* Echinococcus multilocularis `Return to Top`

* Echinococcus multilocularis in liver tissue, stained with hematoxylin and eosin (H&E). Magnification at 200x
Adapted from CDC

* Higher magnification (400x) of the specimen in Figure 1. Notice a pair of refractile hooks (yellow arrows). Cestode hooks do not stain with H&E but may be visible with proper adjustment of the microscope.
Adapted from CDC

* Echinococcus multilocularis in tissue, stained with H&E. Magnification at 200x.
Adapted from CDC

* Higher magnification (400x) of the specimen in Figure 3. Notice the refractile hook (green arrow).
Adapted from CDC

* * *

* Echinostomiasis `Return to Top`

* * *

* Echinostoma spp. `Return to Top`

Echinostoma spp. egg in wet mounts

* Egg of Echinostoma sp. in an unstained wet mount of stool. Image taken at 400x magnification.
Adapted from CDC

Echinostoma spp. adults

* Adult of E. revolutum, stained with carmine. Structures illustrated in this figure include: oral sucker (OS), armed collar (CL), cirrus sac (CS), ventral sucker, or acetabulum (AC), uterus containing eggs (UT), ovary (OV), paired testes (TE), and vitelline glands (VT). This species has been recorded from humans in Taiwan.
Adapted from CDC

Echinostoma sp. in tissue, stained with hematoxylin and eosin (H&E)

* Adult Echinostoma removed during a colonoscopy, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Higher magnification of the anterior end of the specimen in Figure 1. Notice the acetabulum (ventral sucker, AC).
Adapted from CDC

* Higher magnification of the posterior end of the specimen in Figure 1. Notice the vitelline glands (VT) and lobed testes (TE).
Adapted from CDC

* Higher magnification of the specimen in Figures 1-3. Shown here are eggs (EG) within the size range forEchinostoma spp. (roughly 100 micrometers in length, taking into account they are sections and may not be cut in a perfect horizontal plane).
Adapted from CDC

Intermediate hosts of Echinostoma spp.

* Lymnaea sp. This snail genus has been recorded as a second intermediate host for E. malayanum. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Radix sp. This snail genus has been recorded as a first intermediate host for E. hortense and a second intermediate host for E. cinetorchis. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Gyraulus sp. This snail genus has been recorded as an intermediate host for E. cinetorchis. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Viviparus sp. This snail genus has been recorded as a second intermediate host for E. cinetorchis and E. hortense. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Corbicula sp. This bivalve genus has been recorded as a second intermediate host for E. lindoense. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* * *

* Enterobiasis (Pinworm Infection) `Return to Top`

* * *

* Enterobius vermicularis `Return to Top`

Enterobius vermicularis eggs

* Eggs of E. vermicularis in a cellulose-tape preparation.
Adapted from CDC

* Eggs of E. vermicularis in a wet mount.
Adapted from CDC

* Egg of E. vermicularis in an iodine-stained wet mount from a formalin concentrate. Image contributed by the Kansas State Public Health Laboratory.
Adapted from CDC

* Egg of E. vermicularis teased from an adult worm recovered from a colonoscopy. Image contributed by the South Carolina Department of Health and Environmental Control, Bureau of Laboratories.
Adapted from CDC

* Eggs of E. vermicularis viewed under UV microscopy.
Adapted from CDC

* Eggs of E. vermicularis viewed under UV microscopy.
Adapted from CDC

Enterobius vermicularis adult worms

* Adult male of E. vermicularis from a formalin-ethyl acetate (FEA) concentrated stool smear. The worm measured 1.4 mm in length. Image contributed by the Centre for Tropical Medicine and Imported Infectious Diseases, Bergen, Norway.
Adapted from CDC

* Close-up of the anterior end of the worm in Figure 1. The esophagus, divided into muscular and bulbous portions and separated by a short, narrow isthmus, is visible in the image, as are the cephalic expansions.
Adapted from CDC

* Close-up of the posterior end of the worm in Figure 1. Note the blunt end. The spicule is withdrawn into the worm in this specimen.
Adapted from CDC

* Anterior end of an adult female of E. vermicularis, recovered from a colonscopy. Image contributed by the South Carolina Department of Health and Environmental Control, Bureau of Laboratories.
Adapted from CDC

* Posterior end of the worm in Figure 4. Note the long, slender pointed tail.
Adapted from CDC

Enterobius vermicularis in tissue, stained with hematoxylin and eosin (H&E)

* Cross-section of a male E. vermicularis from tissue, stained with H&E. Notice the presence of the alae (blue arrow), intestine (red arrow) and testis (black arrow).
Adapted from CDC

* Cross-section of an adult female E. vermicularis from the same specimen shown in Figure 1. Note the presence of the alae (blue arrow), intestine (green arrow) and ovaries (black arrows).
Adapted from CDC

* Cross section of an adult female E. vermicularis stained with H&E, recovered during a colonoscopy. Note the prominent alae (blue arrow) and the presence of eggs (yellow arrow). Image contributed by Sheboygan Memorial Hospital, Wisconsin.
Adapted from CDC

* Longitudinal section of an adult female E. vermicularis from the same specimen as Figure 3. Note the presence of many eggs.
Adapted from CDC

* Egg of E. vermicularis in a colon biopsy specimen, stained with H&E.
Adapted from CDC

* Egg of E. vermicularis in a colon biopsy specimen, stained with H&E.
Adapted from CDC

* * *

* Enteromonas hominis `Return to Top`

Enteromonas hominis cysts

* Cyst of E. hominis, possessing four nuclei, in a stool specimen stained with iron-hematoxylin.
Adapted from CDC

* Cyst of E. hominis, possessing four nuclei, in a stool specimen stained with iron-hematoxylin.
Adapted from CDC

#### F

* * *

* Fascioliasis `Return to Top`

* * *

* Fasciola hepatica `Return to Top`

Fasciola hepatica eggs

* Egg of F. hepatica in an unstained wet mount, taken at 400x magnification.
Adapted from CDC

* Egg of F. hepatica in an unstained wet mount, taken at 400x magnification.
Adapted from CDC

* Egg of F. hepatica in an unstained wet mount.
Adapted from CDC

F. hepatica adults

* Unstained adult of F. hepatica fixed in formalin.
Adapted from CDC

* Adult of F. hepatica stained with carmine.
Adapted from CDC

F. hepatica adults observed in endoscopic retrograde cholangiopancreatography (ERCP)

* Unstained adult of F. hepatica fixed in formalin.
Adapted from CDC

* Adult of F. hepatica stained with carmine.
Adapted from CDC

Intermediate hosts of Fasciola spp.

* Galba truncately, the main intermediate host of F. hepatica throughout most of the fluke's natural range in Europe and western Asia. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Galba humilis, a host of F. hepatica in Canada and parts of the United States. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Fossaria bulamoides, a host for F. hepatica in the western United States. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Pseudosuccinea columella, a lymnaeid snail that has been introduced into South America and serves as an intermediate host for F. hepatica in Venezuela and Colombia. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* * *

* Fasciolopsiasis `Return to Top`

* * *

* Fasciolopsis buski `Return to Top`

Fasciolopsis buski eggs

* Egg of F. buski in a unstained wet mount.
Adapted from CDC

* Egg of F. buski in a unstained wet mount.
Adapted from CDC

* Egg of F. buski in unstained wet mounts.
Adapted from CDC

* Egg of F. buski in an unstained wet mount of stool.
Adapted from CDC

* Higher magnification (400x) of the egg in Figure 4.
Adapted from CDC

Fasciolopsis buski adults

* Adult fluke of F. buski. Image contributed by Georgia Division of Public Health.
Adapted from CDC

* Adult fluke of F. buski.
Adapted from CDC

Intermediate hosts of F. buski

* Snail in the genus Hippeutis, an intermediate host for F. buski. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Snail in the genus Segmentina, an intermediate host for F. buski. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* * *

* Fleas `Return to Top`

* * *

* Ctenocephalides canis `Return to Top`

* The dog flea, C. canid. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
Adapted from CDC

* * *

* Ctenocephalides felis `Return to Top`

* The cat flea, C. felis. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
Adapted from CDC

* The cat flea, C. felis. Image courtesy of Parasite and Diseases Image Library, Australia (http://www.padil.gov.au/).
Adapted from CDC

* * *

* Free-living amebic infections `Return to Top`

* * *

* Acanthamoeba `Return to Top`

Acanthamoeba spp. cysts

* Cysts of Acanthamoeba spp. in culture.
Adapted from CDC

* Cysts of Acanthamoeba spp. in culture.
Adapted from CDC

* Cyst of Acanthamoeba sp. from brain tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Cyst of Acanthamoeba sp. from brain tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Cysts of Acanthamoeba sp. (green arrows) in tissue, stained with H&E.
Adapted from CDC

Acanthamoeba spp. trophozoites

* Trophozoite of Acanthamoeba sp. from culture. Notice the slender, spine-like acanthapodia.
Adapted from CDC

* Trophozoites of Acanthamoeba sp. from culture. Notice the slender, spine-like acanthapodia.
Adapted from CDC

* Trophozoite of Acanthamoeba sp. in tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Trophozoites of Acanthamoeba sp. in a corneal scraping, stained with H&E.
Adapted from CDC

* * *

* Balamuthia mandrillaris `Return to Top`

Balamuthia mandrillaris cysts

* Cysts of B. mandrillaris.
Adapted from CDC

* Close-up of one of the cysts in Figure 1.
Adapted from CDC

* Cyst of B. mandrillaris.
Adapted from CDC

* Cyst of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Cyst of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of the University of Kentucky Hospital, Lexington, Kentucky.
Adapted from CDC

* Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of the University of Kentucky Hospital, Lexington, Kentucky.
Adapted from CDC

* Cysts of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of Cook Children’s Hospital, Fort Worth, Texas.
Adapted from CDC

* Cyst of B. mandrillaris in brain tissue, stained with H&E. Image courtesy of Cook Children’s Hospital, Fort Worth, Texas.
Adapted from CDC

Balamuthia mandrillaris trophozoites

* Trophozoite of B. mandrillaris in culture.
Adapted from CDC

* Trophozoite of B. mandrillaris in culture.
Adapted from CDC

* Trophozoite of B. mandrillaris in culture.
Adapted from CDC

* Trophozoite of B. mandrillaris in culture.
Adapted from CDC

* Several trophozoites of B. mandrillaris in brain tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* A single trophozoite (green arrow) of B. mandrillaris in brain tissue, stained with H&E.
Adapted from CDC

* A single trophozoite (black arrow) of B. mandrillaris in brain tissue, stained with H&E.
Adapted from CDC

* * *

* Naegleria fowleri `Return to Top`

Naegleria fowleri cysts

* Cyst of N. fowleri in culture.
Adapted from CDC

Naegleria fowleri trophozoites

* Trophozoite of N. fowleri in culture.
Adapted from CDC

* Trophozoites of N. fowleri in culture.
Adapted from CDC

* Ameboflagellate trophozoite of N. fowleri.
Adapted from CDC

* Trophozoite of N. fowleri in CSF, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Trophozoite of N. fowleri in CSF, stained with trichrome. Image courtesy of the Texas State Health Department.
Adapted from CDC

* * *

* Sappinia pedata `Return to Top`

* Four trophozoites (yellow arrows) of S. pedata in brain tissue, stained with hematoxylin and eosin (H&E). In three of the amebae, the two nuclei can easily be seen.
Adapted from CDC

#### G

* * *

* Giardiasis `Return to Top`

* * *

* Giardia duodenalis (syn. G. lamblia, G. intestinalis) `Return to Top`

Giardia duodenalis cysts in wet mounts stained with iodine

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis cyst in a wet mount stained with iodine.
Adapted from CDC

Giardia duodenalis cysts in wet mounts under differential interference contrast (DIC) microscopy

* G. duodenalis cyst in a wet mount under differential interference contrast (DIC) microscopy. Image taken at 1000× magnification.
Adapted from CDC

* Two G. duodenalis cysts in a wet mount under DIC microscopy; image taken at 1000× magnification.
Adapted from CDC

G. duodenalis cysts in trichrome stain

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome.
Adapted from CDC

* G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
Adapted from CDC

* G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
Adapted from CDC

* G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
Adapted from CDC

* G. duodenalis cyst stained with trichrome. Sometimes the cytoplasm of the cyst may retract from the cell wall.
Adapted from CDC

G. duodenalis trophozoites in wet mounts

* G. duodenalis trophozoite in a wet mount stained with iodine.
Adapted from CDC

* G. duodenalis trophozoite in a wet mount under differential interference contrast (DIC) microscopy. Image taken at 1000× magnification.
Adapted from CDC

G. duodenalis trophozoites stained with trichrome

* G. duodenalis trophozoite stained with trichrome.
Adapted from CDC

* G. duodenalis trophozoite stained with trichrome.
Adapted from CDC

* G. duodenalis trophozoite stained with trichrome.
Adapted from CDC

* G. duodenalis trophozoites. Image contributed by the Vermont Department of Health Laboratory.
Adapted from CDC

G. duodenalis trophozoites in unique stains

* G. duodenalis trophozoites in Kohn stain.
Adapted from CDC

* G. duodenalis trophozoites in a Giemsa stained mucosal imprint.
Adapted from CDC

Cysts of Giardia duodenalis and oocysts of Cryptosporidium parvum

* Cysts of G. duodenalis (lower right) and oocysts of Cryptosporidium parvum (upper left) labeled with commercially available immunofluorescent antibodies.
Adapted from CDC

* * *

* Gnathostomiasis `Return to Top`

* * *

* Gnathostoma hispidum `Return to Top`

* * *

* Gnathostoma spinigerum `Return to Top`

Head bulb and cuticular spines of Gnathostoma spinigerum

* Head bulb.
Adapted from CDC

* Cuticular spines of the posterior body part.
Adapted from CDC

Detail of cuticular spines of the anterior body part of G. spinigerum

* Detail of cuticular spines of the anterior body part.
Adapted from CDC

Detail of nondendiculated cuticular spines of G. spinigerum

* Detail of nondendiculated cuticular spines.
Adapted from CDC

* Detail of nondendiculated cuticular spines.
Adapted from CDC

#### H

* * *

* Hepatic capillariasis `Return to Top`

* * *

* Capillaria hepatica `Return to Top`

Capillaria hepatica eggs

* Eggs of C. hepatica in liver stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Eggs of C. hepatica in liver stained with hematoxylin and eosin (H&E). The egg in this figure (1000x magnification) shows the typically striated shell and shallow polar prominences.
Adapted from CDC

* Eggs of C. hepatica in liver stained with H&E.
Adapted from CDC

* Eggs of C. hepatica in liver stained with H&E.
Adapted from CDC

Capillaria hepatica adults

* Cross section of a male C. hepatica in liver tissue, stained with hematoxylin and eosin (H&E). Note the presence of the intestine (blue arrow) and the coiled sections of the testes (black arrows).
Adapted from CDC

* Cross section of C. hepatica in liver tissue, stained with H&E. Note the presence of the intestine (blue arrow) and bacillary bands (black arrows).
Adapted from CDC

* Cross-section of C. hepatica in liver tissue, stained with H&E. Note the presence of a stichocyte (black arrow) and bacillary bands (blue arrows). Image taken at 200x magnification.
Adapted from CDC

* * *

* Heterophyiasis `Return to Top`

* * *

* Heterophyes heterophyes `Return to Top`

Adult of Heterophyes heterophyes

* Adult of H. heterophyes, stained with carmine. In this figure, the following structures are labeled: oral sucker (OS), pharynx (PH), intestine (IN), ventral sucker, or acetabulum (AC), and eggs within the uterus (UT)
Adapted from CDC

Snail intermediate hosts of Heterophyes heterophyes

* Cerithideopsilla cingulata, an intermediate host for H. heterophyes in southeast Asia. Image courtesy of Conchology, Inc, Mactan Island, Philippines
Adapted from CDC

* * *

* Hymenolepiasis `Return to Top`

* * *

* Hymenolepis diminuta `Return to Top`

Hymenolepis diminuta eggs in wet mounts

* Egg of H. diminuta in a wet mount stained with iodine. Four of the hooks are visible at this level of focus. Image courtesy of the Georgia Department of Public Health.
Adapted from CDC

* Egg of H. diminuta in a wet mount stained with iodine. Four of the hooks are visible at this level of focus.
Adapted from CDC

* Eggs of H. diminuta in an unstained wet mount of concentrated stool. Image taken at 200x magnification.
Adapted from CDC

* Higher magnification (400x) of one of the eggs in Figure 3.
Adapted from CDC

* Egg of H. diminuta in an unstained wet mount of concentrated stool. Image taken at 400x magnification.
Adapted from CDC

* Egg of H. diminuta in an unstained wet mount of concentrated stool. Image taken at 400x magnification.
Adapted from CDC

Hymenolepis diminuta proglottids

* Proglottids of H. diminuta stained with carmine. Notice the craspedote form of the proglottids.
Adapted from CDC

* * *

* Hymenolepis nana `Return to Top`

Hymenolepis nana eggs in wet mounts

* Egg of H. nana in an unstained wet mount. Note the presence of hooks in the oncosphere and polar filaments within the space between the oncosphere and outer shell.
Adapted from CDC

* Egg of H. nana in an unstained wet mount. Note the presence of hooks in the oncosphere and polar filaments within the space between the oncosphere and outer shell.
Adapted from CDC

* Egg of H. nana in an unstained wet mount.
Adapted from CDC

* Egg of H. nana in an unstained formalin ethyl acetate (FEA) wet mount. In this image, four of the hooks in the oncosphere are clearly visible. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Egg of H. nana in an unstained wet mount. In this image, the polar filaments in the space between the oncosphere and outer shell are clearly visible.
Adapted from CDC

* Egg of H. nana in an unstained wet mount. In this image, the polar filaments in the space between the oncosphere and outer shell are clearly visible.
Adapted from CDC

Hymenolepis nana eggs, zinc PVA trichrome stain

* Egg of H. nana in a trichrome-stained stool specimen. Although trichrome is not the preferred method for observing helminth eggs, they can be detected this way. The eggs are distorted, probably due to the zinc polyvinyl alcohol (PVA) used for preserving specimens for trichrome stain. Images courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Egg of H. nana in a trichrome-stained stool specimen. Although trichrome is not the preferred method for observing helminth eggs, they can be detected this way. The eggs are distorted, probably due to the zinc polyvinyl alcohol (PVA) used for preserving specimens for trichrome stain. Images courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

Hymenolepis nana proglottids

* Cross-sections of mature proglottids of H. nana stained with hematoxylin and eosin (H&E), taken at 100x. Note the craspedote (overlapping) proglottids.
Adapted from CDC

* Higher magnification of eggs within the proglottid in Figure 1, taken at 400x.
Adapted from CDC

* Higher magnification of the eggs in Figures 1 and 2, taken at 1000x, oil. Hooks do not stain with H&E but are refractile and may be visible in stained specimens with proper adjustment of the microscope. Polar filaments are visible in the egg in the upper right quadrant of the image.
Adapted from CDC

Hymenolepis nana adults

* Three adult specimens of H. nana. Image courtesy of the Georgia Department of Public Health.
Adapted from CDC

* Scolex of H. nana in an unstained wet mount of stool. Image courtesy of Dr. David Bruckner.
Adapted from CDC

* Higher magnification of the scolex in Figure 2. In this image, two of the suckers and the rostellar hooks are clearly visible.
Adapted from CDC

#### I

* * *

* Intestinal amebae `Return to Top`

* * *

* Entamoeba coli `Return to Top`

E. coli cysts in concentrated wet mounts

* Cyst of E. coli in a unstained concentrated wet mount. Six nuclei are visible in this focal plane.
Adapted from CDC

* Cyst of E. coli in a concentrated wet mount stained with iodine. Five nuclei are visible in this focal plane.
Adapted from CDC

* Cyst of E. coli in a concentrated wet mount stained with iodine. Seven nuclei are visible in this focal plane.
Adapted from CDC

* Cyst of E. coli in a concentrated wet mount stained with iodine. Five nuclei are visible in this focal plane.
Adapted from CDC

* Cyst of E. coli in a concentrated wet mount stained with iodine. Five nuclei are visible in this focal plane.
Adapted from CDC

E. coli cysts stained with trichrome

* Immature cyst of E. coli, stained with trichrome. Notice the presence of only two nuclei, and a large glycogen vacuole.
Adapted from CDC

* Mature cyst of E. coli, stained with trichrome. Five nuclei are visible in this focal plane.
Adapted from CDC

* Mature cyst of E. coli, stained with trichrome. In this specimen, at least five nuclei are visible in the shown focal plane.
Adapted from CDC

* Mature cyst of E. coli, stained with trichrome. In this specimen, at least five nuclei are visible in the shown focal plane.
Adapted from CDC

* Mature cyst of E. coli, stained with trichrome. This figure and Figure 6 represent the same cyst shown in two different focal planes. Eight nuclei can be seen between the two focal planes. Also, above the cyst in this figure, a trophozoite of Endolimax nana can be seen.
Adapted from CDC

* Mature cyst of E. coli, stained with trichrome. This figure and Figure 5 represent the same cyst shown in two different focal planes. Eight nuclei can be seen between the two focal planes.
Adapted from CDC

E. coli trophozoites stained with trichrome

* Trophozoite of E. coli stained with trichrome.
Adapted from CDC

* Trophozoite of E. coli stained with trichrome.
Adapted from CDC

* Trophozoites of E. coli stained with trichrome.
Adapted from CDC

* * *

* Entamoeba gingivalis `Return to Top`

E. gingivalis trophozoites stained with trichrome

* Trophozoite of E. gingivalis from culture, stained with trichrome.
Adapted from CDC

* Trophozoite of E. gingivalis from culture, stained with trichrome.
Adapted from CDC

* Trophozoite of E. gingivalis from culture, stained with trichrome.
Adapted from CDC

* Trophozoite of E. gingivalis from culture, stained with trichrome.
Adapted from CDC

* * *

* Entamoeba hartmanni `Return to Top`

E. hartmanni cyst in a wet mount

* Cyst of an E. hartmanni in a wet mount, stained with iodine.
Adapted from CDC

E. hartmanni cysts stained with trichrome

* Cyst of E. hartmanni stained with trichrome. Notice the bluntly-ended chromatoid bodies.
Adapted from CDC

* Cyst of E. hartmanni stained with trichrome.
Adapted from CDC

E. hartmanni trophozoites stained with trichrome

* Trophozoite of E. hartmanni stained with trichrome. Image courtesy of the Kansas Department of Health and Environment.
Adapted from CDC

* Trophozoite of E. hartmanni stained with trichrome.
Adapted from CDC

* Trophozoite of E. hartmanni stained with trichrome. In the upper-right of the image is a cyst-like body of Blastocystis hominis.
Adapted from CDC

* Trophozoite of E. hartmanni stained with trichrome.
Adapted from CDC

* Two trophozoites of E. hartmanni stained with trichrome. Adapted from CDC

Two trophozoites of E. hartmanni stained with trichrome.
Adapted from CDC

* Trophozoite of E. hartmanni stained with trichrome. Adapted from CDC

Trophozoite of E. hartmanni stained with trichrome.
Adapted from CDC

* * *

* Entamoeba histolytica `Return to Top`

* * *

* Entamoeba polecki `Return to Top`

E. polecki cyst in a concentrated wet mount, stained with iodine

* Cyst of E. polecki in a wet mount, stained with iodine. Notice the numerous chromatoid bodies (arrows).
Adapted from CDC

E. polecki cysts stained with trichrome

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

* Cyst of E. polecki stained with trichrome. Notice the large nucleus with a pleomorphic karyosome and numerous variably-shaped chromatoid bodies.
Adapted from CDC

E. polecki trophozoites stained with trichrome

* Trophozoite of E. polecki stained with trichrome.
Adapted from CDC

* Trophozoite of E. polecki stained with trichrome.
Adapted from CDC

* Trophozoite of E. polecki stained with trichrome.
Adapted from CDC

* Trophozoite of E. polecki stained with trichrome.
Adapted from CDC

* Trophozoite of E. polecki stained with trichrome.
Adapted from CDC

* * *

* Endolimax nana `Return to Top`

Endolimax nana cysts in concentrated wet mounts

* Cyst of E. nana in a direct wet mount, viewed under differential interference contrast (DIC) microscopy.
Adapted from CDC

* Cyst of E. nana in a direct wet mount stained with iodine.
Adapted from CDC

E. nana cyst stained with trichrome

* Cysts of E. nana stained with trichrome.
Adapted from CDC

* Cyst of E. nana stained with trichrome.
Adapted from CDC

* Cyst of E. nana stained with trichrome.
Adapted from CDC

* Cyst of E. nana stained with trichrome.
Adapted from CDC

E. nana trophozoites stained with trichrome

* Trophozoite of E. nana stained with trichrome.
Adapted from CDC

* Trophozoites of E. nana stained with trichrome.
Adapted from CDC

* Trophozoite of E. nana stained with trichrome.
Adapted from CDC

* Trophozoite of E. nana stained with trichrome. Image courtesy of the Kansas Department of Health and Environment.
Adapted from CDC

* Trophozoite of E. nana stained with trichrome.
Adapted from CDC

* * *

* Iodamoeba buetschlii `Return to Top`

Iodamoeba buetschlii cysts in concentrated wet mounts

* Cyst of I. buetschlii in an unstained concentrated wet mount. In these cysts, the glycogen vacuole can be seen as a large, oval refractile body.
Adapted from CDC

* Cyst of I. buetschlii in an unstained concentrated wet mount. In these cysts, the glycogen vacuole can be seen as a large, oval refractile body.
Adapted from CDC

* Cyst of I. buetschlii from the same specimen as seen in Figures A and B, but stained with iodine. In this cyst, the glycogen vacuole is more-easily observed as a dark-staining mass in the cyst.
Adapted from CDC

* Cyst of I. buetschlii from the same specimen as seen in Figures A and B, but stained with iodine. In this cyst, the glycogen vacuole is more-easily observed as a dark-staining mass in the cyst.
Adapted from CDC

I. buetschlii cysts stained with trichrome

* Cyst of I. buetschlii stained with trichrome. In this specimen, both the nucleus and large glycogen vacuole are visible.
Adapted from CDC

* Cyst of I. buetschlii stained with trichrome. In this specimen, both the nucleus and large glycogen vacuole are visible.
Adapted from CDC

* Cyst of I. buetschlii stained with trichrome. In this specimen, both the nucleus and large glycogen vacuole are visible (arrow).
Adapted from CDC

* Cyst of I. buetschlii stained with trichrome. In this specimen, both the nucleus and large glycogen vacuole are visible.
Adapted from CDC

I. buetschlii trophozoite stained with trichrome

* Trophozoite of I. buetschlii trophozoite stained with trichrome.
Adapted from CDC

* Trophozoite of I. buetschlii trophozoite stained with trichrome.
Adapted from CDC

* * *

* Intestinal capillariasis `Return to Top`

* * *

* Capillaria philippinensis `Return to Top`

Capillaria philippinensis eggs

* Egg of C. philippinensis in an unstained wet mount of stool.
Adapted from CDC

* Egg of C. philippinensis in an unstained wet mount of stool.
Adapted from CDC

* Egg of C. philippinensis in an unstained wet mount of stool.
Adapted from CDC

* Egg of C. philippinensis in an unstained wet mount of stool.
Adapted from CDC

Capillaria philippinensis adults

* Longitudinal section of an adult of C. philippinensis from an intestinal biopsy specimen stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Longitudinal section of an adult of C. philippinensis from an intestinal biopsy specimen stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Longitudinal section of an adult C. philippinensis from an intestinal biopsy specimen, stained with H&E.
Adapted from CDC

* Higher magnification of Figure 3, showing stichocytes within the adult worm.
Adapted from CDC

* Cross-section of a gravid adult female C. philippinensis from an intestinal biopsy specimen, stained with H&E. Shown in this figure are a bacillary band (blue arrow), the intestine (red arrow) and uterus containing an egg in cross-section (black arrow).
Adapted from CDC

#### L

* * *

* Leishmaniasis (Visceral leishmaniasis, Kala-azar) `Return to Top`

* * *

* Leishmania sp. `Return to Top`

Leishmania amastigotes

* Leishmania sp. amastigotes in a Giemsa-stained tissue scraping.
Adapted from CDC

* Leishmania (Viannia) panamensis amastigotes in a Giemsa-stained tissue scraping. Identification to the species level is not possible based on morphology and other diagnostic techniques such isoenzyme assay or PCR are needed.
Adapted from CDC

* Leishmania (Viannia) panamensis amastigotes in a Giemsa-stained tissue scraping.
Adapted from CDC

* Leishmania (Viannia) panamensis amastigotes in a Giemsa-stained tissue scraping.
Adapted from CDC

* Leishmania sp. amastigotes; touch-prep stained with Giemsa.
Adapted from CDC

* Leishmania sp. amastigotes; touch-prep stained with Giemsa.
Adapted from CDC

* Leishmania tropica amastigotes from an impression smear of a biopsy specimen from a skin lesion. In this figure, an intact macrophage is practically filled with amastigotes (arrows), several of which have a clearly visible nucleus and kinetoplast.
Adapted from CDC

* Leishmania tropica amastigotes from an impression smear of a biopsy specimen from a skin lesion. In this figure, amastigotes are being freed from a rupturing macrophage. Patient had traveled to Egypt, Africa, and the Middle East. Based on culture in NNN medium, followed by isoenzyme analysis, the species was identified as L. tropica.
Adapted from CDC

Leishmania mexicana in tissue stained with hematoxylin and eosin (H&E)

* Amastigotes of Leishmania sp. in a biopsy specimen from a skin lesion, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Leishmania mexicana in a biopsy specimen from a skin lesion stained with H&E. The amastigotes are lining the walls of two vacuoles, a typical arrangement. The species identification was derived from culture followed by isoenzyme analysis.
Adapted from CDC

Leishmania sp. promastigotes from culture

* Leishmania sp. promastigotes from culture.
Adapted from CDC

* * *

* Loaiasis `Return to Top`

* * *

* Loa loa `Return to Top`

Microfilariae of Loa loa

* Microfilaria of L. loa a thick blood smear from a patient from Cameroon, stained with Giemsa. Note the nuclei extending to the tip of the tail to the left of the image.
Adapted from CDC

* Microfilaria of L. loa in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of L. loa in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of L. loa in a thin blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of L. loa in a thin blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of L. loa in a thin blood smear, stained with Giemsa.
Adapted from CDC

* Microfilariae of L. loa captured by the Knotts concentration technique. Image taken at 100x magnification.
Adapted from CDC

* Higher magnification of the microfilariae in Figure 7, taken at 500x oil magnification.
Adapted from CDC

Adults of L. loa

* Adult of L. loa removed from the eye of a patient. Image courtesy of the Georgia State Public Health Laboratory.
Adapted from CDC

* Adult of L. loa removed from the eye of a patient. Image courtesy of the Georgia State Public Health Laboratory.
Adapted from CDC

* * *

* Lymphatic filariasis (Bancroftian filariasis) `Return to Top`

* * *

* Brugia malayi `Return to Top`

* Microfilaria of B. malayi in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of B. malayi in a thin blood smear, stained with Giemsa.
Adapted from CDC

* * *

* Brugia timori `Return to Top`

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* Microfilaria of B. timori in a thick blood smear from a patient from Indonesia, stained with Giemsa and captured at 500x oil magnification. Image from a specimen courtesy of Dr. Thomas C. Orihel, Tulane University, New Orleans, LA.
Adapted from CDC

* * *

* Wuchereria bancrofti `Return to Top`

Microfilariae of Wuchereria bancrofti

* Microfilaria of W. bancrofti in a thick blood smear stained with Giemsa. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Microfilaria of W. bancrofti in a thick blood smear stained with Giemsa. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Microfilaria of W. bancrofti in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Close-up of the anterior end of the worm in Figure 3.
Adapted from CDC

* Close-up of the posterior end of the worm in Figure 3.
Adapted from CDC

Adults of W. bancrofti

* Adults of W. bancrofti. The male worm is on the left; the female is on the right.
Adapted from CDC

#### M

* * *

* Malaria `Return to Top`

* * *

* Plasmodium falciparum `Return to Top`

* * *

* Plasmodium knowlesi `Return to Top`

* * *

* Plasmodium malariae `Return to Top`

* * *

* Plasmodium ovale `Return to Top`

* * *

* Plasmodium vivax `Return to Top`

* * *

* Mansonellosis `Return to Top`

* * *

* Mansonella ozzardi `Return to Top`

Microfilariae of Mansonella ozzardi

* Microfilaria of M. ozzardi in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of M. ozzardi in a thick blood smear, stained with Giemsa.
Adapted from CDC

* Microfilaria of M. ozzardi in a thick blood smears, stained with Giemsa.
Adapted from CDC

* Microfilaria of M. ozzardi in a thick blood smear, stained with Giemsa. Note the hook-like end to the tail in this figure.
Adapted from CDC

* * *

* Mansonella perstans `Return to Top`

Microfilariae of Mansonella perstans

* Microfilaria of M. perstans in a thick blood smear stained with Giemsa, from a patient from Cameroon.
Adapted from CDC

* Microfilaria of M. perstans in a thick blood smear stained with Giemsa, from a patient from Cameroon.
Adapted from CDC

* Microfilaria of M. perstans in a thick blood smear stained with Giemsa, from a patient from Cameroon.
Adapted from CDC

* Microfilaria of M. perstans in a thin blood smear from the same specimen as Figures 1-3.
Adapted from CDC

* Microfilaria of M. perstans in a thin blood smear from the same specimen as Figures 1-4.
Adapted from CDC

* Microfilaria of M. perstans in a thick blood smear stained with Giemsa. Image courtesy of the Parasitology Department, Public Health Lab, Ontario Agency for Health Protection and Promotion, Canada.
Adapted from CDC

* * *

* Mansonella streptocerca `Return to Top`

Microfilariae of Mansonella streptocerca

* Microfilaria of M. streptocerca, fixed in 2% formalin and stained with hematoxylin.
Adapted from CDC

* * *

* Mesocestoidiasis `Return to Top`

* * *

* Mesocestoides spp. `Return to Top`

Mesocestoides spp. proglottids and scoleces

* Proglottids of Mesocestoides sp., collected from the stool of a dog.
Adapted from CDC

* Higher magnification of the proglottids in Figure 1, showing the uterus (red arrow), ovary (blue arrow) and parauterine organ (green arrow).
Adapted from CDC

* Gravid proglottid of Mesocestoides sp. stained with carmine. Shown in this specimen are the uterus (UT) and excretory ducts (ED).
Adapted from CDC

* Mature proglottids of Mesocestoides sp. stained with carmine. Shown in this specimen are the vagina (VA), cirrus sac (CS), bilobed ovary (OV) and numerous testes (TE).
Adapted from CDC

* Scolex of Mesocestoides sp. stained with carmine. In this field, two of the suckers are clearly visible. Note that lack of rostellar hooklets.
Adapted from CDC

Mesocestoides spp. tetrathyridia

* Tetrathyridium of Mesocestoides sp. in the liver of a laboratory-infected mouse.
Adapted from CDC

* * *

* Metagonimiasis `Return to Top`

* * *

* Metagonimus yokogawai `Return to Top`

Metagonimus yokogawai, adult fluke

* Adult M. yokogawai, stained with carmine. In this figure, the following structures are labeled: oral sucker (OS), pharynx (PH), intestine (IN), genitoacetabulum (GA), ovary (OV), the large, paired testes (TE), and eggs within the uterus (EG).
Adapted from CDC

Snail intermediate hosts of M. yokogawai

* Snail in the genus, Semisulcospira. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Snail in the genus, Semisulcospira. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* * *

* Microsporidiosis `Return to Top`

* * *

* Encephalitozoon cuniculi `Return to Top`

* Encephalitozoon cuniculi spores stained with Gram Chromotrope.
Adapted from CDC

* Encephalitozoon cuniculi spores stained with Gram Chromotrope.
Adapted from CDC

* Encephalitozoon cuniculi spores stained with Gram Chromotrope.
Adapted from CDC

* Spores of E. cuniculi from urine stained with Ryan's modified trichrome (Trichrome blue).
Adapted from CDC

* Spores of E. cuniculi from urine stained with Ryan's modified trichrome (Trichrome blue).
Adapted from CDC

* Spores of E. cuniculi from urine stained with Ryan's modified trichrome.
Adapted from CDC

* Spores of E. cuniculi in a kidney biopsy specimen stained with Ryan's modified trichrome.
Adapted from CDC

* * *

* Encephalitozoon hellem `Return to Top`

* Scanning electron micrograph showing an eukaryotic cell bursting and releasing spores of Encephalitozoon hellem to the extracellular medium.
Adapted from CDC

* Monoclonal antibody-based immunofluorescence identification of Encephalitozoon hellem.
Adapted from CDC

* * *

* Encephalitozoon intestinalis `Return to Top`

* Electron micrograph of an eukaryotic cell with Encephalitozoon intestinalis spores and developing forms inside a septated parasitophorous vacuole. The vacuole is a characteristic feature of this microsporidian species.
Adapted from CDC

* Transmission electron micrograph of E. intestinalis depicting developing forms inside a parasitophorous vacuole (red arrows) with mature spores (black arrows).
Adapted from CDC

* Encephalitozoon intestinalis stained with Calcofluor white.
Adapted from CDC

* * *

* Enterocytozoon bieneusi `Return to Top`

* Electron micrograph of an Enterocytozoon bieneusi spore. Arrows indicate the double rows of polar tubule coils in cross section which characterize a mature E. bieneusi spore.
Adapted from CDC

* Enterocytozoon bieneusi spores stained with Chromotrope 2R.
Adapted from CDC

* * *

* Nosema spp. `Return to Top`

* * *

* Pleistophora sp. `Return to Top`

* * *

* Trachipleistophora spp. `Return to Top`

* * *

* Vittaforma corneae `Return to Top`

* * *

* Myiasis (Bot Flies) `Return to Top`

* * *

* Cuterebra spp. `Return to Top`

* Anterior end of a larva of a bot fly in the genus, Cuterebra.
Adapted from CDC

* Posterior end of the larva in Figure 1.
Adapted from CDC

* Adult of Cuterebra sp. Cuterebra spp. are primarily parasites of rodents and lagomorphs, although human infections are rare. Images taken from specimens courtesy of the Georgia Museum of Natural History, University of Georgia, Athens, GA.
Adapted from CDC

* Adult of Cuterebra sp. Cuterebra spp. are primarily parasites of rodents and lagomorphs, although human infections are rare. Images taken from specimens courtesy of the Georgia Museum of Natural History, University of Georgia, Athens, GA.
Adapted from CDC

* * *

* Dermatobia hominis `Return to Top`

* Four larvae of D. hominis, removed from a human host.
Adapted from CDC

* Close-up of the anterior end of one of the larvae from Figure 1, showing the mandibles.
Adapted from CDC

* Close-up of the posterior end of one of the larvae from Figure 1.
Adapted from CDC

* Anterior end of a larva of D. hominis. Image from a specimen courtesy of the Idaho State Health Department.
Adapted from CDC

* Adult of Dermatobia hominis, the human bot fly. Image taken from a specimen courtesy of the Georgia Museum of Natural History, University of Georgia, Athens, GA.
Adapted from CDC

* * *

* Oestrus ovis `Return to Top`

* First instar larva of Oestrus ovis, taken from the conjunctiva of patient in New Zealand. Image courtesy of Auckland City Hospital, Auckland, New Zealand.
Adapted from CDC

* Close-up of the anterior end of the larva in Figure 1, showing the cephalopharyngeal skeleton and mandibles.
Adapted from CDC

* Close-up of the posterior end of the larva in Figure 1.
Adapted from CDC

* First instar larva of O. ovis, collected from the eye of a patient in India presenting with conjunctivitis. Image courtesy of the L V Prasad Eye Institute, Banjara Hills, India.
Adapted from CDC

* * *

* Phormia regina `Return to Top`

* Third instar larva of P. regina, collected in the wound of a patient.
Adapted from CDC

* Close-up of the posterior spiracles of the specimen in Figure 1.
Adapted from CDC

#### O

* * *

* Oesophagostomiasis `Return to Top`

* * *

* Oesophagostomum spp. `Return to Top`

Eggs of Oesophagostomum spp.

* Egg of Oesophagostomum sp. in an unstained wet mount of stool.
Adapted from CDC

* Egg of Oesophagostomum sp. in an unstained wet mount of stool.
Adapted from CDC

L3 infective larvae of Oesophagostomum spp.

* L3 larva of Oesophagostomum sp., obtained via coproculture from the feces of a baboon (Papio ursinus) in South Africa. Note the long, thin, pointed tail. Image courtesy of the UTC Baboon Research Unit, University of Cape Town, South Africa.
Adapted from CDC

* Higher-magnification of the anterior end of the specimen in Figure 1. Note the long cephalic space.
Adapted from CDC

* Mid-section of the specimen in Figures 1 and 2. Notice the alternating triangular-shaped intestinal cells (IN).
Adapted from CDC

* Tail-end of the specimen in Figures 1-3. Notice the long tail space (arrow) and long, tapering tail sheath.
Adapted from CDC

Adults of Oesophagostomum spp.

* Adult of Oesophagostomum sp.
Adapted from CDC

* Higher magnification of the anterior end of the specimen in Figure 1. Note the presence of the cephalic vesicle (CV), cephalic groove (CG) and esophagus (ES).
Adapted from CDC

* Higher magnification of the anterior end of the specimen in Figures 1 and 2. Note the presence of the cephalic vesicle (CV) and corona radiata (CR).
Adapted from CDC

* Posterior end of a female Oesophagostomum sp., showing the pointed tail.
Adapted from CDC

* Posterior end of male Oesophagostomum sp. Note the spicule (SP).
Adapted from CDC

* Same specimen as in Figure 5, but shown in a slightly different focal plane. Note the bursa (BU).
Adapted from CDC

Oesophagostomum spp. in tissue specimens

* Cross-section of an adult of Oesophagostomum sp. in a colon biopsy specimen from a patient from Africa, stained with H&E. Image taken at 40x magnification.
Adapted from CDC

* Higher magnification (200x) of the specimen in Figure 1. Note the large, platymyarian muscle cells (MU), intestine with brush border (IN), and paired reproductive tubes (RT).
Adapted from CDC

* Higher-magnification (200x) of the specimen in Figure 1. Note the large, platymyarian muscle cells (MU) and thick, muscled esophagus (ES).
Adapted from CDC

* * *

* Onchocerciasis (River Blindness) `Return to Top`

* * *

* Onchocerca volvulus `Return to Top`

Microfilariae of Onchocerca volvulus in tissue

* Microfilariae of O. volvulus from a skin nodule of a patient from Zambia, stained with hematoxylin and eosin (H&E). Image taken at 1000x oil magnification. Microfilariae of O. volvulus within the uterus of an adult female. The specimen was taken from the same patient as in Figure 1. Image taken at 500x magnification, oil.
Adapted from CDC

* Microfilariae of O. volvulus within the uterus of an adult female. The specimen was taken from the same patient as in Figure A. Image taken at 500x magnification, oil.
Adapted from CDC

* Microfilariae of O. volvulus from a skin nodule of a patient from Zambia, stained with H&E. Image taken at 1000x oil magnification.
Adapted from CDC

* Coiled microfilaria of O. volvulus, in a skin nodule from a patient from Zambia, stained with H&E. Image taken at 1000x oil magnification.
Adapted from CDC

* Cross-section of an adult female O. volvulus, stained with H&E. Note the presence of many microfilariae within the uterus.
Adapted from CDC

Adults of Onchocerca volvulus in tissue

* Adult of O. volvulus in a subcutaneous nodule, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Adult of O. volvulus in a subcutaneous nodule, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Adult of O. volvulus in a subcutaneous nodule, stained with H&E.
Adapted from CDC

* Adult of O. volvulus in a subcutaneous nodule, stained with H&E.
Adapted from CDC

* Cross-section of an adult female Onchocerca sp. from the biopsy of a scalp nodule from a patient from Liberia. Note the presence of the intestine (blue arrow), uterine tubes (red arrows) and some cuticular nodules (green arrows). Also notice the weak musculature under the thick cuticle. Image courtesy of Drs. Philip LeBoit and Paul Borbeau.
Adapted from CDC

* * *

* Opisthorchiasis `Return to Top`

* * *

* Opisthorchis felineus `Return to Top`

Adults of Opisthorchis felineus

* Adult of O. felineus. Image courtesy of the Web Atlas of Medical Parasitology and the Korean Society for Parasitology.
Adapted from CDC

Intermediate hosts of Opisthorchis spp.

* Bithynia sp., a common intermediate host of Opisthorchis spp. Image courtesy of Michal Maňas.
Adapted from CDC

* * *

* Opisthorchis viverrini `Return to Top`

Eggs of Opisthorchis viverrini in wet mounts

* Egg of O. viverrini in an unstained wet mount of concentrated stool. Image taken at 400x magnification.
Adapted from CDC

* Egg of O. viverrini in an unstained wet mount of concentrated stool. Image taken at 400x magnification
Adapted from CDC

* Egg of O. viverrini in an unstained wet mount of concentrated stool. Image taken at 400x magnification.
Adapted from CDC

* Egg of O. viverrini in an unstained wet mount of concentrated stool. Image taken at 400x magnification.
Adapted from CDC

Adults of O. viverrini

* Adult of O. viverrini. Image courtesy of the Web Atlas of Medical Parasitology and the Korean Society for Parasitology.
Adapted from CDC

#### P

* * *

* Paragonimiasis `Return to Top`

* * *

* Paragonimus spp. `Return to Top`

Eggs of Paragonimus spp. in unstained wet mounts

* Egg of P. westermani in an unstained wet mount.
Adapted from CDC

* Egg of P. westermani in an unstained wet mount.
Adapted from CDC

* Eggs of P. westermani in an unstained wet mount.
Adapted from CDC

* Egg of P. westermani in an unstained wet mount.
Adapted from CDC

Eggs of Paragonimus spp. in tissue

* Eggs of Paragonimus sp. taken from a lung biopsy stained with hematoxylin and eosin (H&E). These eggs measured 80-90 µm by 40-45 µm. The species was not identified in this case.
Adapted from CDC

* Egg of Paragonimus sp. taken from a lung biopsy stained with hematoxylin and eosin (H&E). This egg measured 80-90 µm by 40-45 µm. The species was not identified in this case.
Adapted from CDC

Eggs of Paragonimus kellicotti

* Cross-section of an egg of P. kellicotti in a lung biopsy specimen, stained with periodic acid-Schiff (PAS) stain. Image courtesy of Dr. Gary Procop.
Adapted from CDC

* Longitudinal section of an egg of P. kellicotti in a lung biopsy specimen, stained with hematoxylin and eosin (H&E). Image courtesy of Dr. Gary Procop.
Adapted from CDC

* Egg of P. kellicotti in a Pap-stained bronchial alveolar lavage (BAL) specimen at 100x magnification. Image courtesy of Dr. Gary Procop.
Adapted from CDC

* Eggs of P. kellicotti in a Pap-stained bronchial alveolar lavage (BAL) specimen at 400x magnification. Image courtesy of Dr. Gary Procop.
Adapted from CDC

* Higher magnification (1000x, oil) of the specimen in Figures 3 and 4. Image courtesy of Dr. Gary Procop.
Adapted from CDC

Adults of Paragonimus spp.

* Adult of P. westermani.
Adapted from CDC

* Higher magnification of the adult fluke seen in Figure 1.
Adapted from CDC

* Adult of Paragonimus sp., taken from a lung biopsy specimen stained with hematoxylin and eosin (H&E). Note the presence of the oral sucker. The species was not identified in this case.
Adapted from CDC

* Higher magnification of Figure 3, showing a close-up of the cuticle.
Adapted from CDC

* Adult of P. kellicotti taken from a lung biopsy specimen stained with H&E. This worm is in poor condition, indicating it was probably an old infection. Image courtesy of Dr. Miguel Madariaga, University of Nebraska Medical Center.
Adapted from CDC

* Sections of several adults of P. kellicotti taken from a pleural biopsy stained with H&E. Numbers 1-5 show the individual worms. The integument is gone from most of the worms, as this was probably an old infection, but remnants of the gonad (A, dart) and uterine tubes (B) can be seen. Image courtesy of Dr. Miguel Madariaga, University of Nebraska Medical Center. Image first appeared in: Madariaga, MD, M. G., T. Ruma, MD, and J. H. Theis, MD. 2007. Autochthonous human paragonimiasis in North America. Wilderness & Environmental Medicine. 18(3): 203-205. Image used with permission of © Allen Press Publishing Services.
Adapted from CDC

* * *

* Pediculosis `Return to Top`

* * *

* Pediculosis sp. `Return to Top`

Head and Body Lice adults

* Adult of P. humans capitis.
Adapted from CDC

* Adult female of P. humans capitis. In this specimen, eggs can be observed in the abdomen.
Adapted from CDC

* Adult of P. humanus.
Adapted from CDC

Head and Body Lice nits

* Egg ('nit') of P. humanus capitis, with a first-instar nymph starting to hatch out.
Adapted from CDC

* Empty shell of the nit in Figure 1, the nymph having left.
Adapted from CDC

* * *

* Pentatrichomonas hominis `Return to Top`

Pentatrichomonas hominis trophozoites

* Trophozoite of P. hominis in a stool specimen, stained with trichrome.
Adapted from CDC

* Trophozoite of P. hominis in a stool specimen, stained with trichrome.
Adapted from CDC

* Trophozoite of P. hominis in a stool specimen, stained with trichrome.
Adapted from CDC

* Two trophozoites of P. hominis in a stool specimen, stained with trichrome.
Adapted from CDC

* Trophozoites of P. hominis in a stool specimen, stained with trichrome.
Adapted from CDC

* Trophozoite of P. hominis in a stool specimen, stained with iron hematoxylin.
Adapted from CDC

* * *

* Philophthalmiasis `Return to Top`

* * *

* Philophthalmus spp. `Return to Top`

Philophthalmus spp, adult flukes

* Adult Philophthalmus sp., removed from the conjunctiva of a patient, stained with hematoxylin and eosin (H&E). In this figure, the following structures are labeled: oral sucker (OS), acetabulum (AC), and of the large, paired testes (TE). The positioning of the specimen during preparation did not allow for demonstration of the large pharynx.
Adapted from CDC

* Close up of the anterior end of the worm is Figure 1.
Adapted from CDC

* Adult Philophthalmus sp., removed from the conjunctiva of an artificially-infected chicken, stained with H&E. Illustrated in this figure is one of the large, paired testes (TE).
Adapted from CDC

* Close-up of the anterior end of the worm in Figure 3, showing a close-up of the oral sucker (OS), pharynx (PH), and acetabulum (AC).
Adapted from CDC

Snail intermediate hosts of Philophthalmus spp.

* Melanoides tuberculata, an intermediate host for Philophthalmus spp. in the Middle East.
Adapted from CDC

* Thiara sp., an intermediate host for Philophalmus gralli in southeast Asia and Hawaii. Image courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Semisulcospira spp., intermediate hosts for Philophthalmus spp. Images courtesy of Conchology, Inc, Mactan Island, Philippines.
Adapted from CDC

* Snails thyridium of Mesocestoides sp. in the liver of a laboratory-infected mouse.
Adapted from CDC

* * *

* Pneumocystis pneumonia (PCP) `Return to Top`

* * *

* Pneumocystis jirovecii (previously Pneumocystis carinii) `Return to Top`

Pneumocystis jirovecii trophozoites

* Trophozoites of P. jirovecii in a bronchoalveolar lavage (BAL) specimen from an AIDS patient, stained with Giemsa.
Adapted from CDC

Pneumocystis jirovecii cysts

* Cysts of P. jirovecii in lung tissue, stained with methenamine silver and hematoxylin and eosin (H&E). The walls of the cysts are stained black; the intracystic bodies are not visible with this stain.
Adapted from CDC

* Cysts of P. jirovecii in lung tissue, stained with methenamine silver and hematoxylin and eosin (H&E). The walls of the cysts are stained black; the intracystic bodies are not visible with this stain.
Adapted from CDC

Indirect immunofluorescence using monoclonal antibodies against Pneumocystis jirovecii

* Indirect immunofluorescence using monoclonal antibodies against Pneumocystis jirovecii.
Adapted from CDC

* Direct immunofluorescence antibody stain using monoclonal antibodies that target Pneumocystis jirovecii. This image is from a bronchoalveolar lavage (BAL) specimen from a patient with a malignancy. Image courtesy of Brigham & Women's Hospital, Boston, MA.
Adapted from CDC

#### R

* * *

* Retortamonas intestinalis `Return to Top`

Retortamonas intestinalis, trophozoites

* Trophozoite of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

* Trophozoite of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

Retortamonas intestinalis, cysts

* Cyst of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

* Cyst of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

* Cyst of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

* Cyst of R. intestinalis in a stool specimen, stained with trichrome.
Adapted from CDC

#### S

* * *

* Sarcocystosis `Return to Top`

* * *

* Sarcocystis hominis `Return to Top`

* * *

* Sarcocystis suihominis `Return to Top`

* * *

* Sarcocystis spp. `Return to Top`

Sarcocystis oocysts in wet mounts

* Sporulated oocyst of Sarcocystis sp. in an unstained wet mount, magnification 400x.
Adapted from CDC

* Individual sporocyst of Sarcocystis sp. in an unstained wet mount, magnification 400x.
Adapted from CDC

* Sporulated oocyst of Sarcocystis sp. in unstained wet mounts, magnification 400x.
Adapted from CDC

* Sporulated oocyst of Sarcocystis sp. in unstained wet mounts, magnification 400x.
Adapted from CDC

Sarcocystis oocysts in wet mounts viewed under differential interference contrast (DIC)

* Sporulated oocyst of Sarcocystis sp. in a wet mount viewed under differential interference contrast (DIC) microscopy, magnification 400x.
Adapted from CDC

* Individual sporocyst of Sarcocystis sp. in a wet mount viewed under DIC microscopy, magnification 400x.
Adapted from CDC

* Sporulated oocyst of Sarcocystis sp. in a wet mount viewed under DIC microscopy, magnification 400x.
Adapted from CDC

Sarcocystis oocysts in wet mounts viewed under ultraviolet (UV) microscopy

* Sporulated oocyst of Sarcocystis sp. in a wet mount viewed under UV microscopy, magnification 400x.
Adapted from CDC

* Sporulated oocyst of Sarcocystis sp. in a wet mount viewed under UV microscopy, magnification 400x.
Adapted from CDC

* Individual sporocyst of Sarcocystis sp. in a wet mount viewed under UV microscopy, magnification 400x.
Adapted from CDC

Sarcocystis sarcocysts in tissue

* Sarcocysts of Sarcocystis sp. in muscle tissue, stained with hematoxylin and eosin (H&E). Notice the bradyzoites within each sarcocyst. Images courtesy of the William Beaumont Hospital, Royal Oak, MI.
Adapted from CDC

* Sarcocysts of Sarcocystis sp. in muscle tissue, stained with hematoxylin and eosin (H&E). Notice the bradyzoites within each sarcocyst. Images courtesy of the William Beaumont Hospital, Royal Oak, MI.
Adapted from CDC

* Sarcocysts of Sarcocystis sp. in muscle tissue, stained with H&E. Image courtesy of the William Beaumont Hospital, Royal Oak, MI.
Adapted from CDC

* Higher magnification of one of the sarcocysts in Figure 3, showing many bradyzoites.
Adapted from CDC

* Sarcocyst of Sarcocystis sp. in muscle tissue, stained with H&E (magnification 500x).
Adapted from CDC

* Higher magnification (1000x) of the sarcocyst in Figure 5, showing many bradyzoites.
Adapted from CDC

* * *

* Schistosomiasis (Bilharziasis) `Return to Top`

* * *

* Schistosoma haematobium `Return to Top`

* Egg of S. haematobium in a wet mount of urine concentrates, showing the characteristic terminal spine.
Adapted from CDC

* Egg of S. haematobium in a wet mount of urine concentrates, showing the characteristic terminal spine.
Adapted from CDC

* Egg of S. haematobium in a wet mount of a urine concentrate.
Adapted from CDC

* * *

* Schistosoma intercalatum `Return to Top`

* Egg of S. intercalatum in a wet mount.
Adapted from CDC

* Egg of S. intercalatum in a wet mount.
Adapted from CDC

* * *

* Schistosoma japonicum `Return to Top`

* Egg of S. japonicum in an unstained wet mount. Note the small, inconspicuous spines (red arrows).
Adapted from CDC

* Egg of S. japonicum in an unstained wet mount. Note the small, inconspicuous spines (red arrows).
Adapted from CDC

* Egg of S. japonicum in an unstained wet mount of stool. The spine is not visible in either of these specimens.
Adapted from CDC

* Egg of S. japonicum in an unstained wet mount of stool. The spine is not visible in either of these specimens.
Adapted from CDC

* Egg of S. japonicum in an unstained wet mount of stool.
Adapted from CDC

* Egg of S. japonicum in an unstained wet mount of stool.
Adapted from CDC

* * *

* Schistosoma mansoni `Return to Top`

* Egg of S. mansoni in an unstained wet mount. Images courtesy of the Wisconsin State Laboratory of Hygiene.
Adapted from CDC

* Egg of S. mansoni in an unstained wet mount. Images courtesy of the Wisconsin State Laboratory of Hygiene.
Adapted from CDC

* Egg of S. mansoni in an unstained wet mount. Images courtesy of the Missouri State Public Health Laboratory.
Adapted from CDC

* Egg of S. mansoni in an unstained wet mount. Images courtesy of the Missouri State Public Health Laboratory.
Adapted from CDC

* Eggs of S. mansoni in an unstained wet mount.
Adapted from CDC

* Egg of S. mansoni in an unstained wet mount.
Adapted from CDC

* Adults of S. mansoni. The thin female resides in the gynecophoral canal of the thicker male.
Adapted from CDC

* Adults of S. mansoni. The thin female resides in the gynecophoral canal of the thicker male. Note the tuberculate exterior of the male.
Adapted from CDC

* * *

* Schistosoma mekongi `Return to Top`

* Egg of S. mekongi. Note the inconspicuous spine (red arrow).
Adapted from CDC

* * *

* Sparganosis `Return to Top`

Proliferating spargana in groin tissue

* Proliferating sparganum in groin tissue of a patient from Paraguay, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Proliferating spargana in groin tissue of a patient from Paraguay, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Proliferating sparganum in groin tissue of a patient from Paraguay, stained with hematoxylin and eosin (H&E).
Adapted from CDC

Proliferating spargana in lung tissue

* Proliferating sparganum in lung tissue in a patient from Taiwan, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Higher magnification of the sparganum in Figure 1. In this image, calcareous corpuscles (green arrows) can be seen.
Adapted from CDC

* Proliferating sparganum in lung tissue in a patient from Taiwan, stained with H&E.
Adapted from CDC

* Higher magnification of the sparganum in Figure 3. In this image, calcareous corpuscles (green arrows) can be seen.
Adapted from CDC

Spargana removed from tissue

* Sparganum removed from the chest wall of a patient. The worm measured about 70 mm long. Images from a specimen courtesy of the Oklahoma State Department of Health.
Adapted from CDC

* Sparganum removed from the chest wall of a patient. The worm measured about 70 mm long. Images from a specimen courtesy of the Oklahoma State Department of Health.
Adapted from CDC

* Close-up of the anterior end of the sparganum in Figures 1 and 2. Note the end is thickened and wrinkled, and possesses a characteristic cleft-like invagination.
Adapted from CDC

* Sparganum removed from the ocular conjunctiva of a patient from Taiwan. The worm measured 40 mm long. Image courtesy of Dr. John H. Cross and the Uniformed Services University of the Health Sciences, Bethesda, MD.
Adapted from CDC

* * *

* Sparganum proliferum `Return to Top`

* * *

* Spirometra erinacei `Return to Top`

* * *

* Spirometra mansoni `Return to Top`

* * *

* Spirometra mansonoides `Return to Top`

* * *

* Spirometra ranarum `Return to Top`

* * *

* Strongyloidiasis `Return to Top`

* * *

* Strongyloides stercoralis `Return to Top`

Strongyloides stercoralis first-stage rhabditiform (L1) larvae

* Rhabditiform larva of S. stercoralis in unstained wet mounts of stool. Notice the short buccal canal and the genital primordium (red arrows).
Adapted from CDC

* Rhabditiform larva of S. stercoralis in unstained wet mounts of stool. Notice the short buccal canal and the genital primordium (red arrows).
Adapted from CDC

* Close-up of the anterior end of a rhabditiform larva of S. stercoralis, showing the short buccal canal (red arrow) and the rhabditoid esophagus (blue arrow). Image taken at 1000x oil magnification.
Adapted from CDC

* Rhabditiform larva of S. stercoralis in an unstained wet mount of stool. Notice the short buccal canal and the genital primordium (red arrow).
Adapted from CDC

* Rhabditiform larva of S. stercoralis in an unstained wet mount of stool. Notice the rhabditoid esophagus (blue arrow) and prominent genital primordium (red arrow).
Adapted from CDC

* Rhabditiform larva of S. stercoralis in an unstained wet mount of stool. Notice the prominent genital primordium (blue arrow), rhabditoid esophagus (red arrow) and short buccal canal (green arrow).
Adapted from CDC

Strongyloides stercoralis third-stage filariform (L3) larvae

* Filariform (L3) larva of S. stercoralis in an unstained wet mount.
Adapted from CDC

* Filariform (L3) larva of S. stercoralis in a sputum specimen, stained with Giemsa. Image taken at 200x magnification.
Adapted from CDC

* Higher magnification (1000x oil) of the worm in Figure 2. Notice the notched tail.
Adapted from CDC

Strongyloides stercoralis free-living adults

* Free-living adult male S. stercoralis. Notice the presence of the spicule (red arrow).
Adapted from CDC

* Free living adult male S. stercoralis, showing a spicule (red arrow). A smaller, rhabditiform larva lies adjacent to the adult male.
Adapted from CDC

* Adult free-living female S. stercoralis alongside a smaller rhabditiform larva. Notice the developing eggs in the adult female.
Adapted from CDC

* Adult free-living female S. stercoralis. Notice the row of eggs within the female’s body.
Adapted from CDC

Strongyloides stercoralis in tissue

* Cross-sections of female S. stercoralis (blue arrows) in small intestine tissue, stained with H&E. Image taken at 200x magnification.
Adapted from CDC

* Sections of S. stercoralis from a duodenal biopsy specimen, stained with H&E. Although strongyloidiasis could not be confirmed based on microscopy alone, this case was confirmed using molecular methods (PCR). Image taken at 200x magnification.
Adapted from CDC

* Higher magnification (1000x oil) of a female of S. stercoralis from the same specimen as Figure 1. Notice the intestine (red arrow) and ovaries (blue arrows).
Adapted from CDC

* Higher magnification (1000x oil) of a gravid female of S. stercoralis from the same specimen as Figure 1. Notice the intestine (blue arrow), ovary (red arrow) and an egg within the uterus (green arrow).
Adapted from CDC

* Cross-sections of larvae of S. stercoralis in a intestinal biopsy specimen, stained with H&E. Image taken at 1000x oil magnification. The patient was infected with Strongyloides following transplant of an infected kidney.
Adapted from CDC

* Longitudinal-section of a larva of S. stercoralis from the same specimen as Figure 5. Image taken at 400x magnification.
Adapted from CDC

#### T

* * *

* Taeniasis `Return to Top`

* * *

* Taenia spp. `Return to Top`

Taenia spp. eggs

* Taenia sp. eggs in unstained wet mounts.
Adapted from CDC

* Taenia sp. egg in unstained wet mounts.
Adapted from CDC

* Iodine-stained wet mount of a Taenia sp. egg. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Iodine-stained wet mount of a Taenia sp. egg. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* Unstained Taenia sp. egg, teased from a proglottid of an adult. Four hooks can easily be seen in this image.
Adapted from CDC

Taenia spp. scoleces

* Scolex of T. solium. Note the four large suckers and rostellum containing two rows of hooks.
Adapted from CDC

* Scolex of T. solium. Note the four large suckers and rostellum containing two rows of hooks.
Adapted from CDC

* Scolex of T. saginata. Note the four large suckers and lack of rostellum and rostellar hooks.
Adapted from CDC

Taenia spp. proglottids

* Mature proglottid of T. saginata, stained with carmine. Note the number of primary uterine branches (>12).
Adapted from CDC

* Mature proglottid of T. saginata, stained with India ink. Note the number of primary uterine branches (>12). Image courtesy of the Orange County Public Health Laboratory, Santa Ana, CA.
Adapted from CDC

* Mature proglottid of T. solium, stained with carmine. Note the number of primary uterine branches (<13).
Adapted from CDC

* Mature proglottid of T. solium, stained with India ink. Note the number of primary uterine branches (<13) in the lower specimen.
Adapted from CDC

* Proglottid of T. saginata unstained. Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

* The same proglottid as in Figure 5 injected with India ink, demonstrating the number of primary uterine branches (>12). Image courtesy of the Oregon State Public Health Laboratory.
Adapted from CDC

Cross-sections of Taenia spp. stained with hematoxylin and eosin (H&E)

* Cross-section of a proglottid of Taenia sp., stained with H&E. Note the thick outer tegument and the loose parenchyma filling the body. Calcareous corpuscles (red arrows), characteristic of the cestodes, can be seen in the parenchyma. Image courtesy of the Washington State Public Health Laboratories. Adapted from CDC

Cross-section of a proglottid of Taenia sp., stained with H&E. Note the thick outer tegument and the loose parenchyma filling the body. Calcareous corpuscles (red arrows), characteristic of the cestodes, can be seen in the parenchyma. Image courtesy of the Washington State Public Health Laboratories.
Adapted from CDC

* Cross-section of a proglottid of Taenia sp., stained with H&E. Note the thick outer tegument and the loose parenchyma filling the body. Calcareous corpuscles (red arrows), characteristic of the cestodes, can be seen in the parenchyma. Eggs (blue arrows) can also be seen. Image courtesy of the Washington State Public Health Laboratories.
Adapted from CDC

* Higher magnification of the image in Figure 2, showing a close-up of the eggs. Note the characteristic striations, typical for the taeniids. Not visible in these images are the hooks commonly seen in cestode eggs. Hooks do not stain with H&E but are refractile and are visible with fine focusing of the microscope
Adapted from CDC

* Higher magnification of the image in Figure 2, showing a close-up of the eggs. Note the characteristic striations, typical for the taeniids. Not visible in these images are the hooks commonly seen in cestode eggs. Hooks do not stain with H&E but are refractile and are visible with fine focusing of the microscope.
Adapted from CDC

* Close-up of a cross-section of a Taenia sp. proglottid stained with H&E, showing numerous calcareous corpuscles (yellow arrows). Image courtesy of the Michael E. DeBakey V. A. Medical Center in Houston, TX. Adapted from CDC

Close-up of a cross-section of a Taenia sp. proglottid stained with H&E, showing numerous calcareous corpuscles (yellow arrows). Image courtesy of the Michael E. DeBakey V. A. Medical Center in Houston, TX.
Adapted from CDC

* Close-up of a cross-section of a Taenia sp. proglottid stained with H&E, showing numerous calcareous corpuscles. Image courtesy of Ameripath. Adapted from CDC

Close-up of a cross-section of a Taenia sp. proglottid stained with H&E, showing numerous calcareous corpuscles. Image courtesy of Ameripath.
Adapted from CDC

Taenia spp. adults

* Taenia saginata adult worm. The adult in this image is approximately 4 meters in length. Adapted from CDC

Taenia saginata adult worm. The adult in this image is approximately 4 meters in length.
Adapted from CDC

* Taenia saginata adult worm. Adapted from CDC

Taenia saginata adult worm.
Adapted from CDC

* * *

* Thelaziasis `Return to Top`

* * *

* Thelazia spp. `Return to Top`

Thelazia spp. adults

* Anterior end of a female Thelazia sp. Note the lack of lips (arrow) and prominent striations.
Adapted from CDC

* Mid-section of a female Thelazia sp. Note the prominent striations.
Adapted from CDC

* Mid-section of a gravid female Thelazia sp., showing many typical spirurid-type eggs.
Adapted from CDC

* Posterior end of a female Thelazia sp.
Adapted from CDC

Intermediate hosts of Thelazia spp.

* Fannia canicularis, the lesser house fly. This species has been implicated in the transmission of thelaziasis in the United States and Asia. Image courtesy of Parasite and Diseases Image Library, Australia.
Adapted from CDC

* Musca domestica, the house fly. This species has been implicated in the transmission of thelaziasis in the United States and Asia. Image courtesy of Parasite and Diseases Image Library, Australia.
Adapted from CDC

* * *

* Toxocariasis `Return to Top`

* * *

* Toxocara canis `Return to Top`

Toxocara canis larva hatching

* Toxocara canis larva beginning to hatch.
Adapted from CDC

* T. canis larva hatching.
Adapted from CDC

* T. canis larva.
Adapted from CDC

* * *

* Toxocara cati `Return to Top`

Adult Toxocara cati worms

* Close-up of the anterior end of Toxocara cati, showing the three lips characteristic of ascarid worms.
Adapted from CDC

* Side view of Figure 1, showing the broad, arrow-shaped alae with striations, characteristic of T. cati.
Adapted from CDC

* Close-up of the posterior end of T. cati, showing a prominent point at the end of the “tail.”.
Adapted from CDC

* * *

* Toxoplasmosis `Return to Top`

* * *

* Toxoplasma gondii `Return to Top`

* * *

* Trichinellosis (Trichinosis) `Return to Top`

* * *

* Trichinella spp. `Return to Top`

Encysted larvae of Trichinella in tissue, stained with hematoxylin and eosin (H&E)

* Encysted larvae of Trichinella sp. in muscle tissue, stained with hematoxylin and eosin (H&E). The image magnification is 200x. Adapted from CDC

Encysted larvae of Trichinella sp. in muscle tissue, stained with hematoxylin and eosin (H&E). The image magnification is 200x.
Adapted from CDC

* Encysted larvae of Trichinella sp. in muscle tissue, stained with hematoxylin and eosin (H&E). The image magnification is 400x.
Adapted from CDC

* Encysted larvae of Trichinella sp. in muscle tissue, stained with hematoxylin and eosin (H&E). Image was captured at 400x magnification.
Adapted from CDC

* Encysted larvae of Trichinella sp. in muscle tissue, stained with hematoxylin and eosin (H&E). Image was were captured at 400x magnification.
Adapted from CDC

* Higher-magnification of the larvae in Figure 3. Shown in these cuts are a nucleated stichocyte (ST), prominent lateral chords, or bacillary bands, (LC), immature reproductive tubes (RT), and the intestine (IN). Image captured at 1000x magnification.
Adapted from CDC

Trichinella larvae in tongue tissue of a rat, stained with H&E

* Trichinella larva in tongue muscle of a rat, stained with hematoxylin and eosin (H&E). Image was captured at 400x magnification.
Adapted from CDC

* Trichinella larva in tongue muscle of a rat, stained with hematoxylin and eosin (H&E). Image was captured at 400x magnification.
Adapted from CDC

Larvae of Trichinella from bear meat

* Trichinella larvae in pressed bear meat, partially digested with pepsin.
Adapted from CDC

* Trichinella larva in pressed bear meat, partially digested with pepsin.
Adapted from CDC

* Trichinella larvae in pressed bear meat, partially digested with pepsin.
Adapted from CDC

* Trichinella larvae in pressed bear meat, partially digested with pepsin.
Adapted from CDC

* Larva of Trichinella liberated from bear meat. This larva is from a different case than those shown in Figures 1-4.
Adapted from CDC

* Larva of Trichinella liberated from bear meat. This larva is from a different case than those shown in Figures 1-4.
Adapted from CDC

* * *

* Trichostrongylosis `Return to Top`

* * *

* Trichostrongylus spp. `Return to Top`

Trichostrongylus spp. eggs in wet mounts

* Egg of Trichostrongylus sp. in an unstained wet mount of stool.
Adapted from CDC

* Egg of Trichostrongylus sp. in an unstained wet mount of stool.
Adapted from CDC

* Egg of Trichostrongylus sp. in an unstained wet mount of stool. Image courtesy of the Indiana State Department of Health.
Adapted from CDC

* Egg of Trichostrongylus sp. in an unstained wet mount of stool. Image courtesy of the Indiana State Department of Health.
Adapted from CDC

Trichostrongyle eggs in wet mounts

* Egg of a trichostrongyle in an unstained wet mount of stool from a patient from Afghanistan. Eggs ranged in size from 87-92 µm in length by 50-55 µm in width. Images courtesy of the Leiden University Medical Center, The Netherlands.
Adapted from CDC

* Egg of a trichostrongyle in an unstained wet mount of stool from a patient from Afghanistan. Eggs ranged in size from 87-92 µm in length by 50-55 µm in width. Images courtesy of the Leiden University Medical Center, The Netherlands.
Adapted from CDC

* Egg of a trichostrongyle from the same specimen as Figures 1 and 2. In this egg, a developing larva can be observed.
Adapted from CDC

Trichostrongylus adults

* Anterior end of a female Trichostrongylus sp. Image of a glycerin-mounted specimen, taken at 200x magnification.
Adapted from CDC

* Posterior end of the same specimen as Figure 1. Note the pointed tail. Image taken at 200x magnification.
Adapted from CDC

* Midsection of the same specimen from Figures 1 and 2. Note a row of eggs in the uterus.
Adapted from CDC

* Posterior end of a male Trichostrongylus sp. Note the presence of a bursa (red arrow) and spicule (blue arrow). of a glycerin-mounted specimen, taken at 200x magnification.
Adapted from CDC

* * *

* Trichuriasis (Whip Worm) `Return to Top`

* * *

* Tungiasis `Return to Top`

* * *

* Tunga penetrans `Return to Top`

Tunga penetrans

* Tunga penetrans removed from a lesion on the bottom of the foot of a patient who traveled to Africa. The bulk of the lesion and the posterior part of the flea are marked with a blue arrow. The anterior end of the flea, showing the head, mouthparts and forelegs, is marked with a green arrow. Note the lack of pronotal and genal combs. A single egg (yellow arrow), is also shown.
Adapted from CDC

* Eggs of T. penetrans liberated from the lesion on the second toe of a patient who traveled to Guyana. Image courtesy of Spectrum Health, Grand Rapids, MI.
Adapted from CDC

* Close-up of the eggs from the specimen in Figure 2.
Adapted from CDC

Tunga penetrans lesions and biopsy specimens

* Gross lesion on a patient's foot caused by T. penetrans. Image courtesy of Drs. Mohammed Asmal and Rocio M. Hurtado. Image first appeared at Partners' Infectious Disease Images (http://www.idimages.org), whose content is copyrighted by Partners Healthcare System, Inc., and is used with permission.
Adapted from CDC

* Gross lesion on a patient's foot caused by T. penetrans. Image courtesy of Drs. Mohammed Asmal and Rocio M. Hurtado. Image first appeared at Partners' Infectious Disease Images (http://www.idimages.org), whose content is copyrighted by Partners Healthcare System, Inc., and is used with permission.
Adapted from CDC

* Cross-sections of T. penetrans in tissue, stained with hematoxylin and eosin (H&E).
Adapted from CDC

* Cross-sections of T. penetrans in tissue, stained with hematoxylin and eosin (H&E). In this image, the following structures are labeled: cuticle (CU), gut (GU), and developing eggs (EG).
Adapted from CDC