|A dog with rabies.|
|Classification and external resources|
Zoonoses (//, plural -//, also spelled zoönoses; singular zoonosis (or zoönosis); from Greek: ζῷον zoon "animal" and νόσος nosos "sickness") are infectious diseases of animals (usually vertebrates) that can naturally be transmitted to humans.
Major modern diseases such as Ebola virus disease and salmonellosis are zoonoses. HIV was a zoonotic disease transmitted to humans in the early part of the 20th century, though it has now evolved to a separate human-only disease. Most strains of influenza that infect humans are human diseases, although many strains of swine and bird flu are zoonoses; these viruses occasionally recombine with human strains of the flu and can cause pandemics such as the 1918 Spanish flu or the 2009 swine flu. Zoonoses can be caused by a range of disease pathogens such as viruses, bacteria, fungi and parasites; of 1,415 pathogens known to infect humans, 61% were zoonotic. Most human diseases originated in animals; however, only diseases that routinely involve animal to human transmission, like rabies, are considered direct zoonosis.
Zoonoses have different modes of transmission. In direct zoonosis the disease is directly transmitted from animals to humans through media such as air (influenza) or through bites and saliva (rabies). In contrast, transmission can also occur via an intermediate species (referred to as a vector), which carry the disease pathogen without getting infected. When humans infect animals, it is called reverse zoonosis or anthroponosis.
- 1 History
- 2 Causes
- 3 Lists of diseases
- 4 Use in vaccines
- 5 See also
- 6 References
- 7 Bibliography
- 8 External links
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During most of human prehistory groups of hunter-gatherers were probably very small. Such groups probably made contact with other such bands only rarely. Such isolation would have caused epidemic diseases to be restricted to any given local population, because propagation and expansion of epidemics depend on frequent contact with other individuals who have not yet developed an adequate immune response. To persist in such a population, a pathogen either had to be a chronic infection, staying present and potentially infectious in the infected host for long periods, or it had to have other additional species as reservoir where it can maintain itself until further susceptible hosts are contacted and infected. In fact, for many 'human' diseases, the human is actually better viewed as an accidental or incidental victim and a dead-end host. Examples include rabies, anthrax, tularemia and West Nile virus. Thus, much of human exposure to infectious disease has been zoonotic.
Many modern diseases, even epidemic diseases, started out as zoonotic diseases. It is hard to establish with certainty which diseases jumped from other animals to humans, but there is increasing evidence from DNA and RNA sequencing, that measles, smallpox, influenza, HIV, and diphtheria came to us this way. Various forms of the common cold and tuberculosis also are adaptations of strains originating in other species.
Zoonoses are of interest because they are often previously unrecognized diseases or have increased virulence in populations lacking immunity. The West Nile virus appeared in the United States in 1999 in the New York City area, and moved through the country in the summer of 2002, causing much distress. Bubonic plague is a zoonotic disease, as are salmonellosis, Rocky Mountain spotted fever, and Lyme disease.
A major factor contributing to the appearance of new zoonotic pathogens in human populations is increased contact between humans and wildlife. This can be caused either by encroachment of human activity into wilderness areas or by movement of wild animals into areas of human activity. An example of this is the outbreak of Nipah virus in peninsular Malaysia in 1999, when intensive pig farming began on the habitat of infected fruit bats. Unidentified infection of the pigs amplified the force of infection, eventually transmitting the virus to farmers and causing 105 human deaths.
Similarly, in recent times avian influenza and West Nile virus have spilled over into human populations probably due to interactions between the carrier host and domestic animals. Highly mobile animals such as bats and birds may present a greater risk of zoonotic transmission than other animals due to the ease with which they can move into areas of human habitation.
Because they depend on the human host for part of their life-cycle, diseases such as African schistosomiasis, river blindness, and elephantiasis are not defined as zoonotic, even though they may depend on transmission by insects or other vectors.
Zoonotic transmission can occur in any context in which there is companionistic (pets), economic (farming, etc), predatory (hunting, butchering or consuming wild game) or research contact with or consumption of animals, animal products, or animal derivatives (vaccines, etc).
Contamination of food or water supply
In 2006, a conference held in Berlin was focusing on the issue of zoonotic pathogen effects on food safety, urging governments to intervene, and the public to be vigilant towards the risks of catching food-borne diseases from farm-to-dining table.
Many food outbreaks can be linked to zoonotic pathogens. Many different types of food can be contaminated that have an animal origin. Some common foods linked to zoonotic contaminations include eggs, seafood, meat, dairy, and even some vegetables. Food outbreaks should be handled in preparedness plans to prevent widespread outbreaks and to efficiently and effectively contain outbreaks.
Farming, ranching and animal husbandry
Contact with farm animals can lead to disease in farmers or others that come into contact with infected animals. Glanders primarily affects those who work closely with horses and donkeys. Close contact with cattle can lead to cutaneous anthrax infection, whereas inhalation anthrax infection is more common for workers in slaughterhouses, tanneries and wool mills. Close contact with sheep who have recently given birth can lead to Clamydiosis, or enzootic abortion, in pregnant women, as well as an increased risk of Q fever, toxoplasmosis, and listeriosis in pregnant or the otherwise immunocompromised. Bird flu is common in chickens. While rare in humans, the main public health worry is that a strain of bird flu will recombine with a human flu virus and cause a pandemic like the 1918 Spanish flu. In 2017, free range chickens in the UK were temporarily ordered to remain inside due to the threat of bird flu. Cattle are an important reservoir of cryptosporidiosis and mainly affects the immunocomporomised.
Wild animal attacks
Pets can transmit a number of diseases. Dogs and cats are routinely vaccinated against rabies. Pets can also transmit ringworm and Giardia, which are endemic in both animal and human populations. Toxoplasmosis is a common infection of cats; in humans it is a mild disease although it can be dangerous to pregnant women. Filariasis is caused by Dirofilaria immitis through mosquitoes infected by mammals like dogs and cats. Cat-scratch disease is caused by Bartonella henselae and Bartonella quintana from fleas which are endemic in cats. Toxocariasis is infection of humans of any of species of roundworm, including species specific to the dog (Toxocara canis) or the cat (Toxocara cati). Cryptosporidiosis can be spread to humans from pet lizards, such as the leopard gecko.
(Porcine) herpesviruses, endogenous retroviruses and hepatitis E [possible but unproven]
Outbreaks of zoonoses have been traced to human interaction with and exposure to animals at fairs, petting zoos, and other settings. In 2005, the Centers for Disease Control and Prevention (CDC) issued an updated list of recommendations for preventing zoonosis transmission in public settings. The recommendations, developed in conjunction with the National Association of State Public Health Veterinarians, include educational responsibilities of venue operators, limiting public and animal contact, and animal care and management.
Hunting and bushmeat
- Ebola and Marburg
Lists of diseases
|Disease||Pathogen(s)||Animals involved||Mode of transmission|
|African sleeping sickness||Trypanosoma brucei rhodesiense||range of wild animals and domestic livestock||transmitted by the bite of the tsetse fly|
|Anthrax||Bacillus anthracis||commonly – grazing herbivores such as cattle, sheep, goats, camels, horses, and pigs||by ingestion, inhalation or skin contact of spores|
|Bird flu||Influenza A virus subtype H5N1||wild birds, domesticated birds such as chickens||close contact|
|Brucellosis||Brucella spp.||cattle, goats||infected milk or meat|
|Cat-scratch disease||Bartonella henselae, Bartonella quintana||cats||bites or scratches from infected cats|
|Chagas disease||Trypanosoma cruzi||armadillos, Triatominae (kissing bug)||bite|
|Clamydiosis / Enzootic abortion||Chlamydophila abortus||domestic livestock, particularly sheep||close contact with postpartum ewes|
|Variant Creutzfeldt–Jakob disease||PrPvCJD||cattle||eating meat from animals with bovine spongiform encephalopathy (BSE)|
|Cryptococcosis||Cryptococcus neoformans||commonly – birds like pigeons||inhaling fungi|
|Cryptosporidiosis||Cryptosporidium||cattle and leopard geckos||ingesting cysts from contaminated water|
|Cysticercosis and taeniasis||Taenia solium, Taenia saginata||commonly – pigs and cattle||consuming water or food contaminated with the tapeworm eggs (cysticercosis) or raw or undercooked pork contaminated with the cysticerci (taeniasis)|
|Ebola virus disease (a haemorrhagic fever)||Ebolavirus spp.||chimpanzees, gorillas, fruit bats, monkeys, forest antelope and porcupines||through body fluids, organs|
|Other haemorrhagic fevers (Marburg viral haemorrhagic fever, Lassa fever, Crimean-Congo haemorrhagic fever, Rift Valley fever)||Varies – commonly viruses||varies (sometimes unknown) – commonly camels, hares, hedgehogs, cattle, sheep, goats, horses and swine||infection usually occurs through direct contact with infected animals|
|Echinococcosis||Echinococcus spp.||commonly – dogs, foxes, wolves, sheep, and rodents||Oral ingestion of infective eggs from the feces of an infected, definitive host|
|Filariasis||Dirofilaria immitis||dogs, cats, wolves, coyotes, foxes, jackals, African leopards, beavers, ferrets, reptiles||mosquito bite|
|Foodborne illnesses (commonly diarrheal diseases)||Campylobacter spp., Escherichia coli, Salmonella spp., Shigella spp. and Trichinella spp.||animals domesticated for food production (cattle, poultry)||raw and/or undercooked food made from animals|
|Glanders||Burkholderia mallei.||horses, donkeys||direct contact|
|Giardiasis||Giardia lamblia||beavers, dogs, cats||ingesting spores and cysts in contaminated food and water|
|Hantavirus||Hantavirus spp.||mice, cotton rats and other rodents||exposure to feces, urine or bodily fluids|
|Histoplasmosis||Histoplasma capsulatum||birds, bats||inhaling fungi|
|Influenza||Influenza A virus||horses, pigs, domestic and wild birds, wild aquatic mammals such as seals and whales, minks and farmed carnivores||droplets transmitted through air|
|Leprosy||Mycobacterium leprae||nine banded armadillos ||direct contact, including meat consumption. However, scientists believe most infections are spread human to human.|
|Leptospirosis||Leptospira interrogans||rats, mice, dogs||direct or indirect contact with urine of infected animals|
|Psittacosis||Chlamydophila psittaci||macaws, cockatiels, budgerigars, pigeons, sparrows, ducks, hens, gulls and many other bird species||contact with bird droplets|
|Rabies||Rabies virus||commonly – dogs, bats, monkeys, raccoons, foxes, skunks, cattle, wolves, coyotes, mongooses and cats||through saliva by biting, or through scratches from an infected animal|
|Rat-bite fever||Streptobacillus moniliformis||rats||bites of rats|
|Swine influenza||Any strain of the influenza virus endemic in pigs (excludes H1N1 swine flu, which is a human virus)||pigs||close contact|
|Taenia crassiceps infection||Taenia crassiceps||wolves, coyotes, foxes, moles, rats||contact with soil contaminated with feces|
|Toxocariasis||Toxocara canis and Toxocara cati||dogs, cats||exposure to feces|
|Toxoplasmosis||Toxoplasma gondii||cats, livestock, poultry||exposure to cat feces, contaminated soil and undercooked meat|
|Trichinosis||Trichinella spiralis, Trichinella britovi||rodents, pigs, horses, bears, walruses, foxes||eating infected meat|
|Tuberculosis||Mycobacterium bovis||infected cattle, deer, llamas, pigs, domestic cats, wild carnivores (foxes, coyotes) and omnivores (possums, mustelids and rodents)||milk, exhaled air, sputum, urine, faeces and pus from infected animals|
|Tularemia||Francisella tularensis||lagomorphs (type A) and rodents (type B)||ticks, deer flies, and other insects|
|Q fever||Coxiella burnetii||livestock and other domestic animals such as dogs and cats||inhalation of spores, contact with bodily fluid or faeces|
|West Nile fever||Flavivirus||birds||mosquito bite|
Use in vaccines
The first vaccine against smallpox by Edward Jenner in 1800 was by infection of a zoonotic bovine virus which cased a disease called cowpox. Jenner had noticed that milkmaids were resistant to small pox. Milkmaids contracted a milder version of the disease from infected cows that conferred cross immunity to the human disease. Jenner abstracted an infectious preparation of 'cowpox' and subsequently used it to inoculate persons against smallpox. As a result, smallpox has been eradicated globally, and mass vaccination against this disease ceased in 1981.
- Conservation medicine
- Cross-species transmission
- Emerging infectious disease
- Foodborne illness
- Wildlife disease
- Veterinary medicine
- List of zoonotic primate viruses
- WHO. "Zoonoses". Retrieved 18 December 2014.
- The Merriam-Webster Dictionary. "Zoonosis". Retrieved 18 December 2014.
- Taylor LH, Latham SM, Woolhouse ME (2001). "Risk factors for human disease emergence". Philosophical Transactions of the Royal Society B: Biological Sciences. 356 (1411): 983–989. doi:10.1098/rstb.2001.0888. PMC . PMID 11516376.
- Marx PA, Apetrei C, Drucker E (October 2004). "AIDS as a zoonosis? Confusion over the origin of the virus and the origin of the epidemics". Journal of medical primatology. 33 (5–6): 220–6. doi:10.1111/j.1600-0684.2004.00078.x. PMID 15525322.
- "Zoonosis". Medical Dictionary. Retrieved 30 January 2013.
- Messenger AM, Barnes AN, Gray GC (2014). "Reverse zoonotic disease transmission (zooanthroponosis): a systematic review of seldom-documented human biological threats to animals". PLoS ONE. 9 (2): e89055. doi:10.1371/journal.pone.0089055. PMC . PMID 24586500. Retrieved 18 December 2014.
- Meerburg BG, Singleton GR, Kijlstra A (2009). "Rodent-borne diseases and their risks for public health". Crit Rev Microbiol. 35 (3): 221–70. doi:10.1080/10408410902989837. PMID 19548807.
- Daszak P, Cunningham AA, Hyatt AD (2001). "Anthropogenic environmental change and the emergence of infectious diseases in wildlife". Acta tropica. 78 (2): 103–116. doi:10.1016/S0001-706X(00)00179-0. PMID 11230820.
- Field H, Young P, Yob JM, Mills J, Hall L, Mackenzie J (2001). "The natural history of Hendra and Nipah viruses". Microbes and infection / Institut Pasteur. 3 (4): 307–314. doi:10.1016/S1286-4579(01)01384-3. PMID 11334748.
- Humphrey T, O'Brien S, Madsen M (2007). "Campylobacters as zoonotic pathogens: A food production perspective". International Journal of Food Microbiology. 117 (3): 237–257. doi:10.1016/j.ijfoodmicro.2007.01.006. PMID 17368847.
- Cloeckaert A (2006). "Introduction: emerging antimicrobial resistance mechanisms in the zoonotic foodborne pathogens Salmonella and Campylobacter". Microbes and Infection. 8 (7): 1889–1890. doi:10.1016/j.micinf.2005.12.024. PMID 16714136.
- Frederick, A. Murphy (1999). "The Threat Posed by the Global Emergence of Livestock, Food-borne, and Zoonotic Pathogens". Annals of the New York Academy of Sciences. 894: 20–7. doi:10.1111/j.1749-6632.1999.tb08039.x. PMID 10681965.
- Med-Vet-Net. "Priority Setting for Foodborne and Zoonotic Pathogens" (PDF). Retrieved 5 April 2008.
- "Investigating Foodborne Outbreaks" (PDF). Centers for Disease Control and Prevention. 15 September 2011. Retrieved 5 June 2013.
- "Inhalation Anthrax". www.cdc.gov. Retrieved 2017-03-26.
- "Avian flu: Poultry to be allowed outside under new rules". BBC News. 2017-02-28. Retrieved 2017-03-26.
- Lassen, Brian; Ståhl, Marie; Enemark, Heidi L (2014-06-05). "Cryptosporidiosis – an occupational risk and a disregarded disease in Estonia". Acta Veterinaria Scandinavica. 56 (1): 36. doi:10.1186/1751-0147-56-36. ISSN 0044-605X. PMC . PMID 24902957.
- Prevention, CDC - Centers for Disease Control and. "Toxoplasmosis - General Information - Pregnant Women". www.cdc.gov. Retrieved 2017-04-01.
- Centers for Disease Control and Prevention (2005). "Compendium of Measures To Prevent Disease Associated with Animals in Public Settings, 2005: National Association of State Public Health Veterinarians, Inc. (NASPHV)" (PDF). MMWR. 54 (RR–4): inclusive page numbers. Retrieved 28 December 2008.
- Information in this table is largely compiled from: World Health Organization. "Zoonoses and the Human-Animal-Ecosystems Interface". Retrieved 21 December 2014.
- Clark, Laura. "How Armadillos Can Spread Leprosy". Smithsonianmag.com. Smithsonian.com. Retrieved 16 April 2017.
- Shute, Nancy. "Leprosy From An Armadillo? That's An Unlikely Peccadillo". NPR.org. National Public Radio. Retrieved 16 April 2017.
- Bardosh, K. One Health: Science, Politics and Zoonotic Disease in Africa. 2016. Routledge; London, UK. ISBN 978-1-138-96148-7.
- H. Krauss, A. Weber, M. Appel, B. Enders, A. v. Graevenitz, H. D. Isenberg, H. G. Schiefer, W. Slenczka, H. Zahner: Zoonoses. Infectious Diseases Transmissible from Animals to Humans. 3rd Edition, 456 pages. ASM Press. American Society for Microbiology, Washington, D.C., 2003. ISBN 1-55581-236-8.
- Jorge Guerra González (2010), Infection Risk and Limitation of Fundamental Rights by Animal-To-Human Transplantations. EU, Spanish and German Law with Special Consideration of English Law (in German), Hamburg: Verlag Dr. Kovac, ISBN 978-3-8300-4712-4
- David Quammen (2013). Spillover: Animal Infections and the Next Human Pandemic. ISBN 978-0-393-34661-9.
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