Zoonotic Diseases in Cats

Diseases trasmitted from cats
Many diseases are species specific.  That means that in general, you won’t share an illness with your pet.  Some diseases, however, are zoonotic. That means that they cross species barriers – they are things that you can catch from your pet.  Zoonosis occurs when bacteria, parasites, fungi or viruses are transmitted to humans through blood, saliva, urine and feces. Vectors as well – intermediaries like mosquitoes, fleas and ticks can transmit diseases.

Bacterial Infections

The most common bacterial disease transmitted from cats to humans is Bartonellosis, or Cat-Scratch Disease (or Fever). People usually contract bartonellosis when an infected cat bites or scratches them. Fleas and ticks may also transmit the disease. Symptoms include swollen and inflamed lymph nodes (mostly around the head, neck, and arms), headache, fever, lethargy, loss of appetite, and achy muscles and joints. Healthy individuals generally recover well, although it may take several months to be completely free of the disease. People with compromised immune systems are at risk of more severe infections and complications, which in rare cases may result in death.

People usually contract salmonellosis from consuming food contaminated with salmonella. Cats who consume raw meat or wild birds can transmit salmonella bacteria through their feces. Symptoms include fever, diarrhea, and stomach pains that occur within one to three days of infection. Salmonellosis typically resolves on its own, but serious cases require medical attention.



Parasites encompass both internal and external varieties. External parasites, such as fleas and ticks, can transmit zoonotic diseases and cause inflammation and itching from bites. Internal parasites, including roundworms and hookworms, are transmitted through contact with infected feces. Symptoms may include vomiting, diarrhea (which may contain the worm), shortness of breath, lethargy, nausea, stomach pain, loss of appetite, weight loss, rashes, and coughing or difficulty breathing.

Protozoa, single-celled organisms, are another type of internal parasite. Cats often acquire protozoans from consuming infected birds or rodents, or through fecal contamination from another infected cat. Humans can contract protozoa by cleaning their cat’s litter box, so thorough handwashing after handling pet waste is crucial. Common protozoal diseases transmitted to humans include toxoplasmosis, giardiasis, and cryptosporidiosis, primarily causing diarrhea. Immune-compromised individuals may develop more severe illnesses requiring medical attention.



The most commonly observed zoonotic fungus is ringworm, which often develops in environments with numerous animals living together. Humans can contract the infection from handling an infected animal. Fungal spores are frequently present on shed hair and skin cells, so direct contact with the affected skin is not always necessary. Cats and humans exhibit different reactions to ringworm. Cats typically develop a grey, scaly, dry patch of skin, while humans often experience a round, red, scaly, itchy lesion.



Most viruses are species-specific, meaning a cat virus will spread among cats but not transfer to humans, and vice versa for human viruses. The primary zoonotic virus is rabies, which affects every warm-blooded species and can be transmitted to humans through bites from infected animals. Cats are highly susceptible to rabies, which affects the central nervous system and is typically fatal. While humans have a higher survival rate, the virus can cause permanent damage. Post-exposure vaccination can prevent the disease if the cat has been previously vaccinated against rabies, but once symptoms appear, death usually occurs within ten days. There is no treatment for rabies. In most of North America, vaccinating pets, even strictly indoor cats, is legally required.


If you have a compromised immune system, have someone else clean up after your pet.  Even completely healthy people should take precautions. Vaccinate your cat, keep their food and water dishes clean, avoid directly handling used litter and clean the box completely at regular intervals. Wash your hands thoroughly and often, and keep your cat indoors.

If you have questions or concerns regarding zoonotic diseases, call our veterinary clinic in Newmarket Aurora area at 905-898-1010. Our veterinarian in Newmarket is happy to help you and answer your question.