Tick-borne disease

Tick-borne disease
Other names: Tick-borne illnesses
A feeding tick
Specialty	Infectious disease
Symptoms	Fever[1]
Types	Lyme, babesiosis, anaplasmosis, ehrlichiosis, Rocky Mountain spotted fever[2]
Causes	Caused by viruses, bacteria, or parasites[3]
Diagnostic method	Symptoms and blood test[4]
Differential diagnosis	Measles, meningococcemia, influenza, enterovirus, mononucleosis, viral hepatitis, typhoid fever, thrombotic thrombocytopenia purpura[5]
Treatment	Doxycycline (among others)[4]

Tick-borne diseases are infections spread by tick bites. They are caused by infection with a variety of pathogens, including rickettsia and other types of bacteria, viruses, and protozoa.^[6] The cost is substantial,^[7] affecting ~80 % of cattle worldwide.^[8]

As of 2020^[update] 18 tick-borne pathogens have been identified in the United States^[9] and at least 27 are known globally.^[10][11][12] New diseases have been discovered in the 21st century, by molecular assays and next-generation sequencing.^[13]

Ticks and tick-borne illnesses are increasing.^[14] Tick are spreading into new areas, due in part to the warming temperatures.^[10][15] Tick populations are also affected by changes in the populations of their hosts (e.g. deer, cattle, mice, lizards) and those hosts' predators (e.g. foxes). Diversity and availability of hosts and predators can be affected by deforestation and habitat fragmentation.^[10]

As individual ticks can harbor more than one disease-causing agent, people can be infected with more than one disease at the same time, compounding the difficulty in diagnosis and treatment.^[6] Rates of illness are increasing and the geographic areas in which they are found expand.^[9]

Types[edit | edit source]

Bacterial[edit | edit source]

• Lyme disease or borreliosis^{[16][17][18][19]}
  • Organism: Borrelia burgdorferi sensu lato (bacterium)
  • Vector: at least 15 species of ticks in the genus Ixodes, including deer tick (Ixodes scapularis , I. pacificus, I. ricinus (Europe), I. persulcatus (Asia))
  • Endemic to: The Americas and Eurasia
  • Symptoms: Fever, arthritis, neuroborreliosis, erythema migrans, cranial nerve palsy, carditis, fatigue, and influenza-like illness
  • Treatment: Antibiotics - amoxicillin in pregnant adults and children, doxycycline in other adults
• Relapsing fever (tick-borne relapsing fever, different from Lyme disease due to different Borrelia species and ticks)^{[20][21][clarification needed]}
  • Organisms: Borrelia species such as B. hermsii, B. parkeri, B. duttoni, B. miyamotoi
  • Vector: Ornithodoros species
  • Regions : Primarily in Africa, Spain, Saudi Arabia, Asia in and certain areas of Canada and the western United States
  • Symptoms: Relapsing fever typically presents as recurring high fevers, flu-like symptoms, headaches, and muscular pain, with less common symptoms including rigors, joint pain, altered mentation, cough, sore throat, painful urination, and rash
  • Treatment: Antibiotics are the treatment for relapsing fever, with doxycycline, tetracycline, or erythromycin being the treatment of choice.
• Typhus Several diseases caused by Rickettsia bacteria ^[22]
• Rocky Mountain spotted fever^[23]
  • Organism: Rickettsia rickettsii
  • Vector: Wood tick (Dermacentor variabilis), D. andersoni
  • Region (US): East, Southwest
  • Vector: Amblyomma cajennense
  • Symptoms:Fever, headache, altered mental status, myalgia, and rash
  • Treatment: Antibiotic therapy, typically consisting of doxycycline or tetracycline
• Helvetica spotted fever^{[24][clarification needed]}
  • Organism: Rickettsia helvetica
  • Region(R. helvetica): Confirmed common in ticks in Sweden, Switzerland, France, and Laos
  • Vector/region(s)#1: Ixodes ricinus is the main European vector.
  • Symptoms: Most often small red spots, other symptoms are fever, muscle pain, headache and respiratory problems
  • Treatment: Broad-spectrum antibiotic therapy is needed, phenoxymethylpenicillin likely is sufficient.
• Human granulocytic anaplasmosis (formerly human granulocytic ehrlichiosis or HGE)^[25]
  • Organism: Anaplasma phagocytophilum
  • Vector: Lone star tick (Amblyomma americanum), I. scapularis
  • Region (US): South Atlantic, South-central
• Bartonella: Bartonella transmission rates to humans via tick bite are not well established ^[26] but Bartonella is common in ticks. For example: 4.76% of 2100 ticks tested in a study in Germany ^[27]
• Tularemia^[28]
  • Organism: Francisella tularensis, A. americanum
  • Vector: D. variabilis, D. andersoni
  • Region (US): Southeast, South-central, West, widespread

Viral[edit | edit source]

• Tick-borne meningoencephalitis^[30][31]
  • Organism: TBEV (FSME) virus, a flavivirus from family Flaviviridae
  • Vector: deer tick (Ixodes scapularis), Ixodes ricinus (Europe), Ixodes persulcatus (Russia + Asia)
  • Endemic to: Europe and northern Asia
• Powassan virus/deer tick virus^[32][33]
  • Organism: Powassan virus (POWV), a flavivirus from family Flaviviridae. Lineage 2 POWV is also known as deer tick virus (DTV)
  • Vector: Ixodes cookei, Ix. scapularis, Ix. marxi, Ix. spinipalpusm, Dermacentor andersoni, and D. variabilis
  • Endemic to: North America and eastern Russia
• Colorado tick fever^[34]
  • Organism: Colorado tick fever virus (CTF), a coltivirus from the Reoviridae
  • Vector: Dermacentor andersoni
  • Region: US (West)
• Crimean-Congo hemorrhagic fever^[35]
  • Organism: CCHF virus, a nairovirus, from the Bunyaviridae
  • Vector: Hyalomma marginatum, Rhipicephalus bursa
  • Region: Southern part of Asia, Northern Africa, Southern Europe
• Severe febrile illness^[36]
  • Organism: Heartland virus, a phlebovirus, from the Bunyaviridae
  • Vector: Lone star tick (Amblyomma americanum)
  • Region: Missouri and Tennessee, United States
• Severe febrile illness, headaches, coma in 1/3 patients^[37]
  • Organism: tentatively Alongshan virus, jingmenvirus group in the flavivirus family
  • Vector: tick (likely Ixodes persulcatus, Ixodes ricinus), mosquitoes
  • Region: Inner Mongolia but potentially more widespread

Protozoan[edit | edit source]

• Babesiosis^[38]
  • Organism: Babesia microti, Theileria equi
  • Vector: Ixodes scapularis (deer tick), I. pacificus (western black-legged tick)
  • Region (US): Northeast, West Coast
• Cytauxzoonosis^[39]
  • Organism: Cytauxzoon felis
  • Vector: Amblyomma americanum (Lone star tick)
  • Region (US): South, Southeast

Toxin[edit | edit source]

• Tick paralysis^{[40][clarification needed]}
  • Cause: Toxin
  • Vector (US): Dermacentor andersoni (Rocky Mountain wood tick), D. variabilis (American dog tick or wood tick)
  • Region (US): D. andersoni: East, D. variabilis: East, West coast
  • Vector (Australia): Ixodes holocyclus (Australian paralysis tick)
  • Region (Australia): East

Allergies[edit | edit source]

• Alpha-gal allergy - Alpha-gal syndrome caused by immune reaction to the Alpha-gal sugar molecule introduced by ticks. The immune reaction can leave people with an allergy to red meat.^[41]

Risk assessment[edit | edit source]

For a person or pet to acquire a tick-borne disease requires that the individual gets bitten by a tick and that the tick feeds for a sufficient period of time. The feeding time required to transmit pathogens differs for different ticks and different pathogens. Transmission of the bacterium that causes Lyme disease is well understood to require a substantial feeding period.^{[42][43][clarification needed]}

In general, soft ticks (Argasidae) transmit pathogens within minutes of attachment because they feed more frequently, whereas hard ticks (Ixodidae) take hours or days, but the latter are more common and harder to remove.^[44]

For an individual to acquire infection, the feeding tick must also be infected. Not all ticks are infected. In most places in the US, 30-50% of deer ticks will be infected with Borrelia burgdorferi (the agent of Lyme disease). Other pathogens are much more rare. Ticks can be tested for infection using a highly specific and sensitive qPCR procedure. Several commercial labs provide this service to individuals for a fee. The Laboratory of Medical Zoology (LMZ), a nonprofit lab at the University of Massachusetts, provides a comprehensive TickReport for a variety of human pathogens and makes the data available to the public.^{[45][clarification needed]}

Immunomodulation mechanism[edit | edit source]

In terms of the mechanism via which infection takes hold we find that ticks upon infestation are able to change systemic immune defenses of their hosts. ^[46]

The ticks saliva induces immunomodulation via downregulation of Th1 cytokines and upregulation of Th2 cytokines, as a consequence the host antibody responses is suppressed. This permits pathogen transmission.^[46]

Diagnosis[edit | edit source]

In terms of the diagnosis of Tick-borne disease we find that early in the disease course diagnostic test are limited, however the symptoms demonstrated by the individual as well as the possibility of having been exposed to ticks are important diagnostic information. ^[4][47]

Prevention[edit | edit source]

Ticks tend to be more active during warmer months, though this varies by geographic region and climate. Areas with woods, bushes, high grass, or leaf litter are likely to have more ticks. Those bitten commonly experience symptoms such as body aches, fever, fatigue, joint pain, or rashes. People can limit their exposure to tick bites by wearing light-colored clothing (including pants and long sleeves), using insect repellent with 20%–30% N,N-Diethyl-3-methylbenzamide (DEET), tucking their pants legs into their socks, checking for ticks frequently, and washing and drying their clothing (in a hot dryer).^[48][49]

According to the World Health Organization, tick-to-animal transmission is difficult to prevent because animals do not show visible symptoms; the only effective prevention relies on killing ticks on the livestock production facility.^[50]

Ticks should be removed as soon as safely possible once discovered. They can be removed either by grasping tweezers as close to the mouth as possible and pulling without rotation; some companies market grooved tools that rotate the hypostome to facilitate removal. Chemical methods to make the tick self-detach, or trying to pull the tick out with one's fingers, are not efficient methods.^[44]

Treatment[edit | edit source]

In general, specific laboratory tests are not available for rapid diagnosis of tick-borne diseases. Due to their seriousness, antibiotic treatment is often justified based on presentation alone.^[4]

For example for Lyme disease the antibiotic Doxycycline is recommended^[51]

See also[edit | edit source]

• Arbovirus
• List of diseases spread by invertebrates
• List of insect-borne diseases
• Mosquito-borne disease
• Robovirus
• Tibovirus
• Ticks of domestic animals

References[edit | edit source]

External links[edit | edit source]

• Tick-Borne Diseases: Recommendations for Workers and Employers Archived 2022-03-01 at the Wayback Machine—National Institute for Occupational Safety and Health
• Tickborne Diseases Archived 2022-04-28 at the Wayback Machine—National Center for Infectious Diseases (CDC)
• Tickborne Disease Website Archived 2007-09-29 at the Wayback Machine—Massachusetts Department of Public Health
• Ixodes Scapularis—3D animation of Deer or Blacklegged Tick from US Army site
• Parasitic Insects, Mites and Ticks: Genera of Medical and Veterinary Importance Archived 2022-05-06 at the Wayback Machine Wikibooks