Zoonosis

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Zoonoses are infectious diseases that can be transmitted between animals and humans.

Zoonoses can be caused by a range of disease pathogens including viruses, bacteria, fungi and parasites (see below).

Of 1,415 pathogens known to infect humans, 61% are 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. The term is from Greek: ???? zoon "animal" and ????? nosos "sickness".

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. Taenia solium infection is one of the neglected tropical diseases with public health and veterinary concern in endemic regions.

Video Zoonosis

Types of Pathogens

Classification of Zoonoses

Viral - HIV/AIDS, rabies, Influenza, feline cowpox, monkeypox, chikungunya hantavirus, Herpes B,

Rift Valley Fever, West Nile, Orf, human or avian influeza virus, etc.

Bacterial - bordetella bronchiseptica, Erysipelothrix rhusiopathiae, clostridium difficile, burkolderia mallei (aka Glanders), Helicobacter, pseudomonas (pseudoglanders), pasteurella multocida (pasteurellosis), rat bite fever (streptovacillus), streptococcus, yersinia enterocolitica, anthrax, brucellosis, etc.

Parasitic - angiostrongyliasis, anisakiasis, chagas (trypanosoma cruzi), dirofilariasis (roundworm), Baylisacariasis, cysticercosis (taenia), cryptosporidiosis, dipylidiasis, echinococcosis, giardiasis, hookworm, leishmaniasis, toxocariasis, toxoplasmosis, trichinellosis,  

Fungal - cryptococcosis, dermatophytosis, sporotrichosis, histoplasmosis,

Arthropods - scabies, other acariasis

Prions - transmissible spongiform encephalopathy (i.e. mad cow)

Maps Zoonosis

Modes of Transmission

Inhalation

Ingestion

Dermal absorption

Animal bites

Arthropod Vectors

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Transmission Prevention

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At Risk and Vulnerable Populations

Zoonotic transmissions occur where 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.).

Occupational Exposures

Veterinary personnel

Animal husbandry - agriculture

Animal product processing (i.e. meat packing factories)

Animal research facility workers

Zoo and Aquarium workers

Wildlife rehabilitation or others with wildlife contact (i.e. hunters)

Pet store workers

Other Vulnerable Groups

Pregnant women

Infants

Immunosuppressed

Pet owners

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Pressing Issues - Where Human Lifestyle and Zoonotic Diseases Connect

Vaccines

I. vaccines and Humans

II. Vaccines and Animals

The first vaccine against smallpox by Edward Jenner in 1800 was by infection of a zoonotic bovine virus which caused a disease called cowpox. Jenner had noticed that milkmaids were resistant to smallpox. 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.

Antibiotic Use and Resistance

Climate Change

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Emerging Zoonoses

• Ebola Hemorrhagic Fever (Ebola virus disease)

• Middle East Respiratory Syndrome (MERS)

• Chikungunya Virus

• H1N1 Influenza Virus (Swine Flu)

• Avian Influenza (Bird Flu)

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Zoonotic diseases

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Contamination of food or water supply

The most significant zoonotic pathogens causing foodborne diseases are Escherichia coli O157:H7, Campylobacter, Caliciviridae, and Salmonella.

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. Echinococcosis is caused by a tapeworm which can be spread from infected sheep by food or water contaminated with feces or wool. 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 immunocompromised.

• Rabies

Insect vectors

• African sleeping sickness
• Dirofilariasis
• Eastern equine encephalitis
• Japanese encephalitis
• Saint Louis encephalitis
• Tularemia
• Venezuelan equine encephalitis
• West Nile fever
• Western equine encephalitis
• Zika fever

Pets

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. Dirofilariasis 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.

Exhibition

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.

Secondary transmission

• Ebola and Marburg

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See also

• Conservation medicine
• Cross-species transmission
• Emerging infectious disease
• Foodborne illness
• Wildlife disease
• Veterinary medicine
• List of zoonotic primate viruses

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References

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Bibliography

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External links

• AVMA Collections: Zoonosis Updates
• WHO tropical diseases and zoonoses
• Detection and Forensic Analysis of Wildlife and Zoonotic Disease
• Publications in Zoonotics and Wildlife Disease

Source of the article : Wikipedia