Cat Healthy Protocols

18- Zoonotic Diseases

A zoonotic disease is one that is naturally transmitted between humans and animals. At least 150 diseases are known to be zoonotic, varying in severity from being a nuisance to having a fatal outcome. Diseases such as rabies are transmitted by animals showing obvious signs of illness, whereas other diseases such as toxoplasmosis or Cat Scratch Disease (bartonellosis) can be transmitted by cats that appear healthy. Fortunately, a few simple precautions are needed to reduce the risk of transmission of zoonotic disease.

This section highlights the most important zoonotic diseases that people living in Canada can acquire from cats. The information given here is an overview only, and readers with an interest in a particular disease are encouraged to obtain additional information from their physician, their cat’s veterinarian, local public health officials, or the references listed at the end of this document.

Transmission of Zoonoses

There are several routes by which people can become infected with a zoonotic agent:

How Great is the Risk?

The American Association of Feline Practitioners Feline Zoonoses Guidelines conclude that humans are unlikely to acquire infectious diseases from healthy adult, parasite-free cats. Many zoonotic agents, including Cryptosporidium and Salmonella, are more likely to be transmitted between people than to be acquired from an animal companion. People who are at increased risk of developing serious illness when exposed to zoonotic organisms should take extra precautions to minimize their risk of infection. Examples of people who may be at increased risk include:

According to the Centers for Disease Control Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents (see Resources), immunocompromised individuals obtaining a new pet should adopt only flea-free cats over 6 months of age with no history of diarrhea or illness. If diarrhea occurs, veterinary care should be sought, and a fecal sample from the affected pet should be examined for Cryptosporidium, Salmonella, Giardia, and Campylobacter. Effective, regular flea prevention and control will reduce or eliminate the risk of bartonellosis in both indoor and indoor/outdoor cats.

General Guidelines for Preventing Transmission of Zoonotic Diseases

TOXOPLASMOSIS is of special concern to pregnant women, because women who are infected with Toxoplasma gondii for the first time during pregnancy can transmit the infection to the fetus. Depending upon the age of the fetus when the mother is exposed, infection may result in abortion or still birth, or cause brain or ophthalmic disease in the fetus. Although it is likely that exposure to tissue cysts from handling or eating undercooked meat is the most common route whereby pregnant women are exposed to this disease, it is also possible to acquire toxoplasmosis from contact with sporulated oocysts in materials contaminated with cat feces such as soil, water, or cat litter. Contact with cat feces less than 24 hours old is very unlikely to transmit toxoplasmosis as it takes 24 hours or more for the organism to become infective after shedding. For this reason, litter boxes should be scooped at least twice daily. However, pregnant women and immunocompromised people are encouraged to avoid all contact with cat feces and to wear gloves when handling material (including soil) that may be contaminated with cat feces. For women who have been previously exposed to toxoplasmosis, protective immunity likely will have developed prior to pregnancy.

Toxoplasma oocysts are not found on a cat’s hair coat, and there appears to be little or no risk of infection from handling or petting a cat. Since cats acquire toxoplasmosis by eating prey (such as mice) or undercooked meat, cats eating only commercial cat foods are very unlikely to be infected with Toxoplasma.

BARTONELLOSIS (Cat Scratch Disease) is believed to be the most common direct zoonosis that can be transmitted from cats to people. Cats become infected with Bartonella primarily through fleas carrying the organism, and the disease appears to be more prevalent in areas with a warm and moist climate and therefore high levels of flea infestation. As the name implies, Cat Scratch Disease is transmitted by scratches from cats with flea dirt on their nails. People become infected when the organism in the flea dirt is inoculated into their skin through a scratch. As play behaviour may involve scratching, kittens may provide a greater risk. In immunocompetent people, Bartonella infection is usually mild and self-limiting although symptoms may last for months in some patients. In immunocompromised people, bartonellosis may be a life-threatening infection.

Serologic testing of cats for Bartonella infection is not useful, nor is antibiotic treatment of healthy cats. Adult cats with no history of flea infestation are considered unlikely to transmit bartonellosis. Therefore, the main way to prevent transmission of Bartonella infection is through prevention of flea infestations.

TABLE 1 Disease agents that can be acquired from freshly passed cat feces

Campylobacter jejuni Subclinical, or mild gastroenteritis Subclinical or gastroenteritis, myalgia, Guillain-Barre syndrome, arthralgia Oral-fecal (ingestion of fecal material or contaminated food) Cats: Avoid predation or feeding raw meat

People: Wash hands, avoid contact with animal feces

Salmonella species Subclinical, or gastroenteritis (“songbird fever”), occasionally abortion or neonatal death. Symptomatic carriers may shed Salmonella Subclinical, or gastroenteritis and fever Ingestion of fecal material or contaminated food Cats: Avoid predation or feeding raw poultry

People: Wash hands, avoid contact with animal feces and turtles

Cryptosporidium felis Subclinical or small bowel diarrhea; some cats may show weight loss and anorexia Gastroenteritis (especially children); may be fatal in people with compromised immune systems Ingestion of fecal material or contaminated food or water Cats: Perform periodic fecal examinations, avoid predation and access to contaminated food or water supplies

People: Wash hands, avoid handling affected animals, boil or filter contaminated surface water

Giardia (Risk from contact with infected cats is very low as people are typically infected with different types of Giardia than cats) Subclinical or diarrhea Flatulence, nausea, and diarrhea Oral-fecal (ingestion of cysts from feces, or drinking water or food contaminated with excrement) Cats: Perform periodic fecal examinations or testing

People: Wash hands, avoid drinking contaminated water

TABLE 2 Disease agents acquired from fecal contamination of the environment
(agents that require time outside the cat to become infectious)

Roundworms (Toxocara cati) Usually kittens, often subclinical; may result in failure to thrive, fever, mild gastroenteritis Visceral larva migrans (eosinophilia, abdominal pain, nausea, fever, cough, anorexia, hepatomegaly) and ocular larva migrans (severe intraocular inflammation) Ingestion of larvated eggs in soil or water contaminated with cat feces. Eggs passed in feces require at least 1 week to become infective Cats: Perform fecal testing regularly, administer anthelmintics and/or preventive medication, prevent predation

People: Wash hands after handling cats or cleaning litter boxes, avoid exposure to soil or water contaminated with cat feces

Toxoplasmosis (Toxoplasma gondii) Usually subclinical. Occasionally fever, neurologic, respiratory, ophthalmic, or liver disease. Congenital infections in kittens may be fatal Usually subclinical or flu-like disease (fever, malaise); may be fatal or cause neurologic or ophthalmic disease in immune deficient persons; if infection occurs during pregnancy, may cause abortion, stillbirth, or ophthalmic or neurologic disease in fetus Ingestion of sporulated oocysts in soil or water (oocysts become infectious 1-5 days after being passed in cat feces), or ingestion of tissue cysts in infected undercooked meat Cats: Prevent hunting. Feed commercial diet or cooked food only

People: Avoid contact with cat feces, dispose of soiled cat litter daily, use gloves and wash hands after contact with cat feces, contaminated litter, or soil; avoid ingestion or handling of undercooked meat

TABLE 3 Other zoonotic agents

Rabies (Lyssavirus) Progressive and fatal neurologic disease: variable changes in behaviour including restlessness and aggression, ascending paralysis, vocalization Progressive and fatal neurologic disease; between 2000 and 2016, 4 cases of human rabies have been reported in Canada, in 2016, an outbreak of rabies in raccoons appeared in southwestern Ontario Animal bites or wounds contaminated with saliva from an animal with rabies Cats: Vaccinate. Avoid contact with wildlife (raccoons, bats, skunks)

People: Protect high risk people through pre-exposure vaccination, post-exposure prophylaxis after contact with rabid animal, avoid contact with wildlife including bats and raccoons

Bartonellosis (Bartonella species) Usually subclinical; may develop fever, lethargy, and enlarged lymph nodes; possibly associated with uveitis, neurologic disease Cat Scratch Disease: enlarged lymph nodes, malaise, fever, myalgia, fatigue, headache; occasionally conjunctivitis, arthralgia; in people with immunosuppression, may cause severe disease (bacillary peliosis, bacillary angiomatosis) Scratches (particularly from kittens) from cats with fleas, or contact with fleas Cats: Provide regular flea control; minimize exposure to fleas; declawing does not reduce risk of disease transmission

People: Avoid scratches particularly from kittens; promptly treat scratches from cats by washing thoroughly with soap and water

Ringworm (Microsporum canis and others) Subclinical, or skin disease (patchy hair breakage and loss, crusts, scale) Superficial skin disease: initially red and circular lesions, mildly pruritic; later becoming dry and scaly. Nails and scalp may also be infected; young, elderly and immunocompromised people are at greatest risk Direct contact with spores on fur or skin of affected cats or spores shed in the environment Isolate and treat affected cats, wash hands after handling cats, wash bedding used by affected cats, avoid skin contact and wear gloves when handling cats with known or suspect infection (particularly kittens from group housing)


American Association of Feline Practitioners Zoonoses Guidelines
Available free at:

European Advisory Board on Cat Diseases – feline infectious disease fact sheets:

Centers for Disease Control and Prevention – Healthy Pets Healthy People (US):

Centers for Disease Control and Prevention/National Institutes of Health/HIV Medicine Association Guidelines for Prevention and Treatment of Opportunistic Infections in HIV-Infected Adults and Adolescents (2013)
Available free at:

Birds Be Safe Cat Collars: