Animal Transmitted Diseases

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A zoonotic disease or zoonosis (plural is zoonoses) is any disease of animals that can be transmitted to people. This list includes some zoonotic diseases and related topics that affect people in Washington State. For brochures, reports, and other handouts, see our animal and vectorborne disease publications. For regulations on preventing animal transmitted disease, including reporting requirements, see our zoonotic disease rules and guidelines.

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Washington residents should contact their local health jurisdictions for assistance.



Anthrax is caused by a spore-forming bacteria and most commonly occurs in wild and domestic herbivore mammals. It's rare to find infected animals in the United States. People can become infected with anthrax by handling products from infected animals or by breathing in anthrax spores from infected animal products such as wool, hides, leather, or hair. Rare cases of inhalational, cutaneous (skin), and gastrointestinal anthrax have been connected to contaminated imported animal hide drums. Gastrointestinal anthrax can occur after eating undercooked meat from infected animals. Anthrax can also be used as a weapon. This occurred in the United States in 2001 when letters containing anthrax spores were sent through the postal system.


Arbovirus, short for arthropod-borne virus, is a name given to viruses that are transmitted by arthropods. Mosquitoes are the most common vectors of arboviral diseases such as West Nile virus in Washington.

Avian Influenza

Avian influenza (bird flu) refers to the disease caused by avian influenza A viruses. These viruses occur naturally among wild waterbirds, and can infect poultry and other birds and animals. On rare occasions avian influenza viruses can infect people causing illness. Usually this has happened to people who have had direct or close contact with infected poultry. Influenza viruses constantly change, and certain changes may allow the avian influenza virus to spread easily between people. This could trigger large flu outbreaks or a pandemic.


B virus (Herpes B)

B virus, or Cercopithecine herpesvirus 1, is commonly found in macaque monkeys, including rhesus, cynomolgus, pig-tailed, stump-tailed, and Japanese macaques. The B virus can be shed lifelong in their saliva and all adult macaques should be assumed to be carriers. The B virus can be transmitted to people through bites and scratches, and can cause acute neurological disease and fatal encephalitis.

Bites from Animals

Animals bites can result in serious injuries and potential exposure to zoonotic diseases such as rabies. It is estimated that about 4.5 million people in the United States are bitten by dogs each year, and about 1 in 5 of those people require medical attention. Children are at higher risk for serious injury from animal bites. Contact your health care provider or local health department anytime an animal bite occurs. They can help make sure proper rabies prevention measures are followed after a bite. Bats are the most likely animal in Washington State to have rabies, but any mammal can become infected.


Brucellosis is a bacterial infection that can affect goats and other livestock such as sheep and cows and wild ruminants such as deer, elk and bison. Brucellosis is rare in livestock in the United States but common in many other countries. Brucellosis causes abortion or stillbirth in animals. Infected animals can shed the bacteria in milk and in vaginal fluids after birthing or abortion. People can be infected through direct contact with the infected animal's placenta and other birthing fluids, from consuming unpasteurized milk and other dairy products from infected animals, or rarely, in a laboratory. Symptoms in people vary, but serious disease can occur. Dogs can become infected with a strain of the bacteria specific to canines, but this type rarely spreads to people.



Campylobacteriosis is a bacterial infection. The bacteria are commonly found in the feces of infected animals and in food products contaminated with the bacteria during processing or preparation. Raw or undercooked chicken is one of the most common sources of human infection.

Cat Scratch Disease

Cat scratch disease is a mild to severe bacterial disease caused by Bartonella henselae. Young cats and kittens are the most likely source of human infection. The infection is transmitted between cats by fleas. Infected flea droppings on the cat's fur are the source of human infections, which are spread from the cat to a person by a cat bite, scratch, or lick. Cats rarely show signs of illness but people can develop skin lesions, fever, or in severe cases, systemic (whole body) infection.


Cryptococcal disease is caused by breathing in the Cryptococcus fungus. The symptoms of this rare disease include a long-lasting cough, sharp chest pain, shortness of breath, severe headache, confusion, fever, night sweats, and unintended weight loss. There are different types of Cryptococcus, such as C. gattii and C. neoformans. Cryptococcus gattii lives on trees and in the soil and there are no particular precautions that will prevent this disease. The benefits of outdoor recreation and activities far outweigh the risk of acquiring this cryptococcal disease. Cryptococcus neoformans primarily affects people with impaired immune systems and can also affect pets such as dogs and cats. Cryptococcus neoformans can be found in bird droppings, such as pigeons. If the dried bird droppings are stirred into the air, people can inhale the fungus.

Cyanobacteria (Blue-green algae)

Cyanobacteria, or blue-green algae, are found in lakes, rivers, ponds, and other water bodies. Sometimes cyanobacteria produce toxins and people can develop skin irritations after contact. If toxic cyanobacteria are swallowed, a person or animal can have stomach cramps, vomiting, diarrhea, sore throat, fever, headache, muscle and joint pain, or nerve and liver damage. Avoid swimming in or having contact with algal blooms. Don't let pets drink or swim in waters with algal blooms.


Dead Animal Disposal

As dead animals decompose, bacteria that may normally be contained within the animal's body can be released, exposing people to potential disease-causing pathogens. Disposal of domestic animals and pets that have died are the responsibility of their owner. Small animals can be bagged in plastic and placed in the outdoor garbage can for disposal. If the owner of the domestic animal is not known or can't be located, contact local animal control. For disposal of dead wild animals, contact your city, county, or local health department for advice.


E. coli

Escherichia coli (E. coli) are bacteria that live in the guts of animals and people and can be shed in feces. Most strains of E. coli are harmless, but some, such as E. coli O157:H7, can cause serious disease in people. People are typically infected when they eat contaminated food, but infection can also occur through direct contact with animals or objects that infected animals have contaminated, or from infected people. Infection with E. coli O157:H7 and other Shiga-toxin producing E. coli can cause diarrhea and in some cases a severe complication called hemolytic uremic syndrome, which is more likely to occur in young children and the elderly.


Fish Tank Granuloma (Mycobacteriosis)

Fish tank granuloma is caused by the bacteria, Mycobacterium marinum, which can be found in aquatic environments. The bacteria often occur in aquarium fish or food fish raised under crowded conditions. People can get infected through direct contact with contaminated water sources, including aquarium water. The bacteria enter through breaks in the skin. The infection can cause skin lesions, usually on the fingers or hands. Skin lesions may heal or in some cases may persist for months. For people with weakened immune systems, the bacteria may cause joint and bone infections. People who clean aquariums should wear gloves and wash their hands thoroughly afterwards to prevent infection.



Giardia are tiny parasites that can infect the intestines of people and many types of animals. People become infected through contact with an infected person, animal, or ingesting fecally contaminated food or water. A person may have no signs of illness, or there may be mild to severe symptoms including diarrhea, stomach cramps, gas, fever, nausea, vomiting, and headache. Giardia parasites have been found in dogs, cats, ruminants like goats and cows, and wild animals. Beavers may be a source of contamination of lake or stream water.



Hantavirus pulmonary syndrome is a severe respiratory disease caused by inhaling dust that has been contaminated with deer mice droppings, urine, or saliva. The disease begins with flu-like symptoms, but as it worsens, shortness of breath is caused by fluid filled lungs. About one-third of all hantavirus pulmonary syndrome cases are fatal. Avoid stirring up rodent nests, droppings, or other rodent-contaminated materials into the air. Follow rodent control measures of keeping rodents out of our living areas, trapping them, and properly cleaning up after rodents to help prevent hantavirus pulmonary syndrome.


Histoplasmosis is a disease caused by a fungus called Histoplasma capsulatum. The fungus is found in the soil and in bat or bird droppings, primarily in Midwestern states. The fungal spores can become airborne when soil or droppings are disturbed. Inhaling the spores causes infection. Symptoms vary greatly, but the disease primarily affects the lungs.


Importing Animals

The importation of animals increases the potential for the introduction of infectious diseases. In 2003, African rodents with monkeypox were imported into the United States, which later led to several people getting ill who had contact with infected pet prairie dogs. More recently, soldiers overseas have adopted and imported dogs that later were found to be infected with rabies. Federal, state, and local animal importation laws help control the introduction of zoonotic diseases.



Leptospirosis is a bacterial disease that infects both humans and a wide range of animals. It occurs worldwide but is more common in temperate and tropical areas of the world. Some people infected with leptospirosis will have no symptoms at all, and some people will become severely ill. Some wild and domestic animals, such as cattle, pigs, dogs, raccoons, and rodents, carry the bacteria and pass them in their urine. People become ill following direct contact with urine or tissues from infected animals, or exposure to contaminated soil, food, or water.


Listeriosis is a rare but serious disease caused by Listeria monocytogenes. It is usually acquired by eating or drinking foods contaminated with the bacteria. Unpasteurized cheese or other dairy products, hot dogs, and cold cuts are the foods most likely to transmit listeriosis. Infection in cattle and goats can cause them to abort. When this occurs, the placental remains are heavily contaminated and contact with these remains can spread the infection to people. Listeriosis is especially hazardous to pregnant women, newborns, the elderly, and people with weakened immune systems.

Lyme Disease

Lyme disease, a bacterial disease, caused by Borrelia burgdorferi, is transmitted by the bites of infected ticks. Ticks become infected by feeding on infected rodents. It is the most common tick-borne disease in the United States, but is relatively rare in Washington when compared to other areas of the country. The classic symptom of Lyme disease is usually an expanding target-shaped or "bull's-eye" rash which starts at the site of the tick bite. Fever, headache, muscle aches and joint pain may also occur. If left untreated, later symptoms can include recurring joint pain, heart disease, and nervous system disorders. Animals such as dogs and horses can also develop Lyme disease.

Lymphocytic Choriomeningitis

The primary host of lymphocytic choriomeningitis virus is the common house mouse. Pet rodents can become infected after being in contact with wild house mice infesting pet stores or homes. People can develop lymphocytic choriomeningitis following exposure to rodent urine, droppings, saliva, or nesting material. Symptoms of illness may be similar to the flu, or may cause meningitis (inflammation of the lining of the brain and spinal cord).


MRSA in Animals

Methicillin-resistant Staphylococcus aureus (MRSA) is a type of bacteria that is resistant to certain antibiotics. MRSA causes skin infections and people and animals can transmit MRSA to each other. Direct skin-to-skin contact is the most common way MRSA is spread. People and pets can carry MRSA on their skin or in their nose and not show signs of illness. Transmission involving animals is rare compared with person-to-person.


Petting Zoos and Animal Exhibits

Certain venues encourage or permit the public to be in contact with animals. These settings include county or state fairs, petting zoos, animal swap meets, pet stores, zoologic institutions, circuses, carnivals, educational farms, livestock-birthing exhibits, educational exhibits at schools and child-care facilities, and wildlife photo opportunities. Although human-animal contact has many benefits, infectious disease outbreaks and injuries have been associated with these settings. Following established rules and guidelines, such as hand washing after contact with animals, will help reduce infectious disease outbreaks associated with animals in public settings.


Plague is a serious infection of humans caused by bacteria the bacteria, Yersinia pestis. The bacteria are present in wild rodents and their fleas. People are infected through the bite of an infected flea, through a cut or break in the skin while handling infected animals, or through respiratory droplets from and infected person or animal. Although wildlife in Washington occasionally test positive for plague, human plague infections are extremely rare in our state. The last case occurred in Yakima County in 1984, and involved an animal trapper.

Psittacosis (Parrot fever)

Psittacosis is a bacterial disease caused by Chlamydophila psittaci. People usually become infected after inhaling contaminated dust from feathers or bird droppings. Direct contact with infected birds and bites can also spread the disease. Psittacine birds such as cockatiels, parrots, and parakeets are common carriers of the bacteria, but many other types of birds can be infected. Some infected birds show no signs of disease but can shed the bacteria when stressed from illness, moving to a new home, nutritional deficiencies, or overcrowding. The same respiratory disease in birds is called avian chlamydiosis, ornithosis, or parrot fever.


Q Fever

Q fever is a bacterial disease caused by Coxiella burnetii and primarily affects cattle, sheep, and goats, although other livestock and pets can carry the bacteria. Most animals have no symptoms, but infection may cause abortion in sheep and goats. The bacteria can be shed in the birth products, urine, feces, and milk of infected animals. The disease in people ranges from no symptoms to severe or chronic illness. People can be infected through direct contact with or by inhaling barnyard dust contaminated with dried placental material, birth fluids, or urine and feces from infected animals, or ingesting unpasteurized dairy products made from infected animals.



Rabies is a severe viral disease that affects the central nervous system. All warm-blooded mammals, including people, can get rabies. Rabies is almost always fatal if treatment is not begun soon after exposure to the virus. Most people in our state are exposed to rabies by being bitten by a bat. Bats are the only known natural reservoir for rabies in Washington State. Elsewhere in the United States, rabies reservoirs include skunks, foxes, and raccoons. While human rabies is rare in the United States, it is a significant disease worldwide, causing 55,000 deaths a year - most of those coming from bites of infected dogs. In the United States, human rabies is controlled by vaccinating dogs and cats and by giving a series of shots to people after they've been exposed to a potentially rabid animal.

Raccoon Roundworm

Baylisascaris is an intestinal roundworm found in raccoons. People, and other animals, become infected when they accidentally ingest Baylisascaris eggs from soil, water, or objects that have been contaminated with raccoon feces. Once ingested, these eggs hatch into larvae in the intestine and travel throughout the body, affecting the organs and muscles. Children or developmentally disabled people are at a higher risk for infection when they spend time outdoors, because they are more likely to put contaminated fingers, soil, or objects into their mouths. People who work with raccoons or spend time in raccoon habitats are also at increased risk.

Rat Bite Fever

Rat bite fever is a bacterial disease that is spread to people through bites or scratches from rats. Symptoms include abrupt fever, vomiting, headache, muscle, back, and joint pain, and then a rash on the hands and feet and swollen joints. Other animals such as mice, gerbils, squirrels, cats, and dogs can get infected and may or may not get sick with rat bite fever, but they can spread the bacteria. Rat bite fever is rare in the United States, but it's not a notifiable disease, so exact numbers of cases are unknown. People who handle rats as part of their work or live in homes infested with wild rats are at higher risk of getting this disease. People who have pet rats may also be at risk for infection.

Ringworm (Dermatophytosis)

Ringworm, also known as dermatophytosis, is not a worm at all, but a fungus that grows on the skin. Many animals can get ringworm, including dogs, cats, cattle, sheep, goats, pigs, rodents, rabbits, and birds. People are infected by direct contact with an infected animal or person - most infections are spread person-to-person. Ringworm on a person's head usually shows as a bald patch of scaly skin and elsewhere on the body it can cause a red, ring-shaped rash that may be itchy. Spores of the ringworm fungus can survive for a long time on carpet, furniture, or other surfaces, and cause infections.

Roundworm (Toxocariasis)

Toxocariasis, or roundworm infection, is caused by a parasite that is commonly found in the intestines of dogs and cats. Roundworm eggs, which can survive for long periods of time in the environment, are present in infected dog and cat feces. People can get roundworm infections through direct contact with contaminated feces or through ingesting roundworm eggs. Children are more likely to become infected since they play in areas where the ground may be fecally contaminated by dogs and cats. Although most people with roundworm infection have no symptoms, sometimes the roundworm larvae can move through the body and damage body tissue, such as the eye.

Rules and Guidelines

Regulations and guidelines to help prevent diseases from being transferred from animals to people. Rabies vaccination requirement for pet owners, animal vendor or venue operator responsibilities, disease reporting requirements and more.



Salmonellosis is a bacterial infection. The bacteria are shed in the feces of infected people and animals. Most infections happen when a person eats or drinks food contaminated with Salmonella bacteria. Contact with animals or objects that animals touch have also led to salmonellosis. Animals that often carry Salmonella include livestock and poultry (chicks, ducklings), reptiles (turtles, snakes, lizards), amphibians (frogs, salamanders, toads), rodents, and even fish in aquariums. Salmonella can cause serious disease, especially in young children, the elderly, and people with weakened immune systems.


Tick-borne Relapsing Fever

Tick-borne relapsing fever is a disease caused by the bacteria Borrelia hermsii. Ticks feed on rodents and pick up the bacteria. The disease is transmitted to people following the bite of an infected tick. The disease is characterized by relapsing (recurrent) periods of fever and other symptoms lasting for 2 to 7 days, disappearing for about 4 to 14 days, and then reoccurring. Most people become infected while staying in old cabins in rural, mountainous areas during the summer months. Keeping rodents out of cabins and sleeping areas will reduce the risk of being fed upon by ticks at night.


Toxoplasmosis is caused by a parasite that has a complex life cycle. Cats are required for the life cycle of the parasite but other animals, such as sheep, goats and pigs are commonly infected. People can get toxoplasmosis by eating fecally contaminated raw vegetables or undercooked meat. It can also be spread through contact with infected cat feces. People at greater risk of illness are those with weakened immune systems, children, and pregnant women. Symptoms begin with a mild flu-like illness. Severe disease can occur if the parasite invades the muscles, nervous system, heart, lungs, or eye. Women who are pregnant should not clean cat litter boxes.


Tularemia is a bacterial disease caused by Fransicella tularensis and is most commonly found in wild animals such as rodents, squirrels, rabbits, hares and beavers. People and their pets can get tularemia through direct contact with infected dead or ill animals, or their blood or tissue, and through bites of infected animals. Tularemia can also be transmitted by the bite of an infected arthropod (ticks, biting flies), ingestion of contaminated water or raw meat, and inhalation of bacteria from soil that is stirred into the air via farming or landscaping tools. Prevent exposure to tularemia by not handling dead or ill animals, avoiding bare-hand contact with blood and raw meat from wild animals, and avoiding animal, tick, and deer fly bites.


Valley Fever (Coccidioidomycosis)

Valley Fever is caused by breathing in the fungus Coccidioides. The fungus is known to live in the soil, and has been found in soils of south-central Washington. The symptoms of this rare disease include tiredness, cough, fever, shortness of breath, headaches, night sweats, and muscle aches or joint pain. Valley Fever can infect the lungs, or other parts of the body in severe cases.


West Nile Virus

West Nile virus is spread by mosquitoes that pick up the virus after feeding on infected wild birds. People, horses, and certain types of birds are most often affected by this virus. Most people infected with the virus don't get sick, but some may have an illness ranging from mild to severe. In the severe forms, West Nile virus affects the nervous system and may result in meningitis, encephalitis, paralysis, or death.


Yellow Fever

Yellow fever is a disease caused by the yellow fever virus. It is spread by infected mosquitoes in tropical and subtropical regions of Africa and South America. Illness ranges from fever to bleeding and jaundice (yellowing skin or eyes). A vaccine is available and recommended for most people who plan to travel to areas with yellow fever risk.


Zika Virus

Zika virus is spread to people through mosquito bites. The most common symptoms of Zika virus disease are fever, rash, joint pain, and conjunctivitis (red eyes). The illness is usually mild with symptoms lasting from several days to a week. Severe disease requiring hospitalization is uncommon. Anyone who is living in or traveling to an area where Zika virus is found and who has not already been infected with the virus is at risk for infection. CDC recommends that pregnant women not travel to areas currently experiencing Zika outbreaks, and that women intending to become pregnant talk with their healthcare providers before they travel. Zika virus infection during pregnancy has been shown to be linked to birth defects such as microcephaly.

Content Source: Zoonotic Disease Program