Pathogen

WikiDoc Resources for Pathogen

Articles

Most recent articles on Pathogen

Most cited articles on Pathogen

Review articles on Pathogen

Articles on Pathogen in N Eng J Med, Lancet, BMJ

Media

Powerpoint slides on Pathogen

Images of Pathogen

Photos of Pathogen

Podcasts & MP3s on Pathogen

Videos on Pathogen

Evidence Based Medicine

Cochrane Collaboration on Pathogen

Bandolier on Pathogen

TRIP on Pathogen

Clinical Trials

Ongoing Trials on Pathogen at Clinical Trials.gov

Trial results on Pathogen

Clinical Trials on Pathogen at Google

Guidelines / Policies / Govt

US National Guidelines Clearinghouse on Pathogen

NICE Guidance on Pathogen

NHS PRODIGY Guidance

FDA on Pathogen

CDC on Pathogen

Books

Books on Pathogen

News

Pathogen in the news

Be alerted to news on Pathogen

News trends on Pathogen

Commentary

Blogs on Pathogen

Definitions

Definitions of Pathogen

Patient Resources / Community

Patient resources on Pathogen

Discussion groups on Pathogen

Patient Handouts on Pathogen

Directions to Hospitals Treating Pathogen

Risk calculators and risk factors for Pathogen

Healthcare Provider Resources

Symptoms of Pathogen

Causes & Risk Factors for Pathogen

Diagnostic studies for Pathogen

Treatment of Pathogen

Continuing Medical Education (CME)

CME Programs on Pathogen

International

Pathogen en Espanol

Pathogen en Francais

Business

Pathogen in the Marketplace

Patents on Pathogen

Experimental / Informatics

List of terms related to Pathogen

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]

A pathogen or infectious agent is a biological agent that causes disease or illness to its host.[1] The term is most often used for agents that disrupt the normal physiology of a multicellular animal or plant. However, pathogens can infect unicellular organisms from all of the biological kingdoms. The term pathogen is derived from the Greek παθογένεια, "that which produces suffering." There are several substrates and pathways where by pathogens can invade a host; the principal pathways have different episodic time frames, but soil contamination has the longest or most persistent potential for harboring a pathogen.

The body contains many natural defenses against some of the common pathogens (such as Pneumocystis) in the form of the human immune system and by some "helpful" bacteria present in the human body's normal flora. However, if the immune system or "good" bacteria is damaged in any way (such as by chemotherapy, human immunodeficiency virus (HIV), or antibiotics being taken to kill other pathogens), pathogenic bacteria that were being held at bay can proliferate and cause harm to the host. Such cases are called opportunistic infections.

Some pathogens (such as the bacterium Yersinia pestis, which may have caused the Black Plague, and the Variola and Malaria viruses) have been responsible for massive numbers of casualties and have had numerous effects on afflicted groups. Of particular note in modern times is HIV, which is known to have infected several million humans globally, along with Severe Acute Respiratory Syndrome (SARS) and the Influenza virus. Today, while many medical advances have been made to safeguard against infection by pathogens, through the use of vaccination, antibiotics, and fungicide, pathogens continue to threaten human life. Social advances such as food safety, hygiene, and water treatment have reduced the threat from some pathogens.

## Contents

* 1 Types of pathogens
* 2 Transmission of pathogens
* 3 Transmission to vascular plants
* 4 See also
* 5 External links
* 6 References

## Types of pathogens

[edit | edit source]

Below is a listing of different types of notable pathogens as categorized by their structural characteristics, and some of their known effects on infected hosts.

Pathogen  | Examples  | Typical effects

|
|

Bacteria | Escherichia coli | urinary tract infection, peritonitis, foodborne illness
Mycobacterium tuberculosis | tuberculosis
Bacillus anthracis | anthrax
Salmonella | foodborne illness
Staphylococcus aureus | toxic shock syndrome
Streptococcus pneumoniae | pneumonia
Streptococcus pyogenes | strep throat
Helicobacter pylori | Stomach ulcers
Francisella tularensis | tularemia
Viruses | Hepatitis A, B, C, D and E | liver disease
Influenza virus | flu
Herpes simplex virus | herpes
Molluscum contagiosum virus | rash
Human immunodeficiency virus | AIDS
Protozoa | Cryptosporidium | cryptosporidiosis
Giardia lamblia | giardiasis
Plasmodium | malaria
Trypanosoma cruzi | chagas disease
Fungi | Pneumocystis jirovecii | opportunistic pneumonia
Tinea | ringworm
Candida | candidiasis
Histoplasma capsulatum | histoplasmosis
Cryptococcus neoformans | cryptococcosis
Parasites | Roundworm | .
Tapeworm | .
Proteins | Prions | BSE, vCJD

## Transmission of pathogens

[edit | edit source]

Main article: Transmission (medicine)

One of the primary pathways by which food or water become contaminated is from the release of untreated sewage into a drinking water supply or onto cropland, with the result that people who eat or drink contaminated sources become infected. In developing countries most sewage is discharged into the environment or on cropland as of 2007; even in developed countries there are periodic system failures resulting in a sanitary sewer overflow. This is the typical mode of transmission for the infectious agents of (at least):

* Cholera
* Hepatitis A
* Polio
* Rotavirus

## Transmission to vascular plants

[edit | edit source]

In the case of terrestrial vascular plants, pathogenic infection can occur by contact with foliage, and also from root uptake of soil pathogens. The latter pathway explains why some plant families such as orchids are more disease resistant, since they rely upon fungal hyphae to supply nutrients rather than root structures, which have larger radii for conveying certain pathogens.

## See also

[edit | edit source]

* Bioaerosol
* Epidemiology
* Foodborne illness
* Indoor air quality
* Microbiology
* Soil contamination

## External links

[edit | edit source]

* Globally Important Human Pathogens List (pdf file)
* New Research to locate passengers releasing pathogens inside airline cabins.
* Information on enterobacterial pathogens can be found at the NIAID Enteropathogen Resource Integration Center (ERIC)

cs:Patogen da:Patogen de:Krankheitserreger id:Patogen it:Microrganismi patogeni lv:Patogēns nl:Pathogeen no:Patogen ur:ممراض qu:Unquchiq simple:Pathogen su:Kuman sv:Smittämne

## References

[edit | edit source]

1. ↑ http://www.medterms.com/script/main/art.asp?articlekey=6383 Definition of pathogen

Template:WH Template:WS