Zoonosis – Yourself and Your Cat

Four week old Persian kitten

Moochi at four weeks old
© Pelaqita Persians

Zoonotic diseases (also called zoonosis) that can pass from animals to humans. Most diseases are species specific. Good hygiene can help avoid most zoonotic diseases by disinfecting contaminated areas, washing hands after handling contaminated items (including cats) and wearing rubber gloves to prevent infectious matter entering skin wounds. Most diseases pose no threat to humans and treatable by your doctor. Rabies while rare, is a dangerous disease and any zoonotic disease can pose a dangerous threat to those with a poor immune system.

The most common zoonosis are: toxoplasmosis (a protozoan), and Ringworm (fungus). Ringworm is common in Persian cats and other long-haired cat breeds.

  • Toxoplasmosis (a protozoan) can be spread from cats (and a wide variety of other sources) to humans. A pregnant woman who contracts toxoplasmosis risks having a baby with congenital defects.
  • Ringworm is a fungal skin disease. Ringworm is more irritating than dangerous to people. Ringworm can cause scarring (due to constant scratching) and may be of concern to individuals with poor immune systems.

This article's purpose is to provide a short, simple guide to zoonosis and is not meant to be all-inclusive and focuses on cat-related zoonosis. Many people have had zoonosis-related diseases and have never realized it!


Ringworm is the most common zoonosis in cats. Persian cats can be non-systematic carriers (meaning it does not have any symptoms of Ringworm but sheds the spores and keeps infecting any other cat in your household or keeps giving it to you). Vets who treat cats with Ringworm, are familiar with seeing owners with red, scaly, itchy patches of skin. Ringworm is NOT a worm but a fungus; it normally causes circular scaly patches. Some strains do not fluoresce and must be cultured in the laboratory to provide a diagnosis. Up to 40% of cats may have Ringworm without showing any symptoms.

It can be difficult to eradicate Ringworm from a household if left untreated. Fungal spores can fly off the cat and land some distance away or get into the home's ventilation system, on furniture, clothes, etc. Cat treatment is usually by oral medication (AND by Lyme dips). Further information on the treatment for Ringworm. Human treatment is usually by antifungal creams. When a cat owner gets Ringworm they often think it is eczema and seek treatment. As with other skin diseases, the red scaly circular patches may be itchy and continued scratching may cause scarring.


Secondary infectious agents often follow viral or mycobacterial infections. Bacteria may be present in diarrhea which results in cross-infection (solid stools buried in litter are less infectious). Common zoonotic bacteria include species of campylobacter, streptococcus and staphylococci; these generally respond to antibiotics. However, some cat breeders now routinely dose their cats with antibiotics in an attempt to reduce disease in the cattery. The overuse of antibiotics leads to an increase in antibiotic-resistant strains of bacteria. Pelaqita Persians does not believe in using an antibiotic unless there is some type of infection.

Various conditions can cause feline conjunctivitis, including bacterial or viral infections; conjunctivitis caused by a foreign body may lead to a secondary bacterial infection. Since some of these germs can also infect humans, it is wise to follow basic hygiene precautions when handling cats with conjunctivitis. Conjunctivitis is easily treatable in cats (and humans) with eye drops and eye ointments - often containing the same active ingredients!

Carefully clean cat bite wounds with antiseptic or antibiotic cleansers and apply an antibiotic ointment. Immediately see your veterinarian if there are signs of wound inflammation, persistent swelling or fever which may require antibiotics. Most healthy adults will recover without treatment; but you may not wish to risk your health.

Salmonella is more common in the feces of cats fed raw meat or those that catch wild birds. Infection follows a fecal-oral route (you clean the litter tray and scratch your lip without first washing your hands).

Cat Scratch Disease (Cat Scratch Fever)

The bacteria, Bartonella henselae, causes cat scratch fever. It does not usually cause fever. Fleas carry the bacteria from cat to cat. Cat Scratch Disease causes systemic illness and lymph node lesions and can be serious in individuals with poor immune response. Antibiotics usually cures the disease without complications in healthy young adults. Clearing the bacteria from infected cats requires long-term antibiotic treatment. However, cats may be infected indefinitely.



Cats pick up Toxoplasma infection by ingesting infected prey. In humans, toxoplasmosis symptoms may be flu-like, usually there are no symptoms. Infection is more serious in individuals with poor immune response. Women who contract toxoplasmosis while pregnant may suffer congenital infection.

Cats are not the main source of toxoplasmosis infection in humans. Avoid contact with potentially contaminated soil or wear rubber gloves. Wash with soap and water afterwards. Do not touch mouth with soil-tainted fingers. Cover children's sandboxes to prevent contamination by cats.

Clean out litter trays daily (i.e., before oocysts can become infectious). Wear rubber gloves for this task (if pregnant, you may wish to get another family member to empty the litter trays). Preferably disinfect litter tray with hot soapy water and then bleach the box. Disinfect potentially contaminated litter boxes with scalding water and bleach. Wash hands after handling litter trays; even if you have worn gloves.

Protect cats from infection (or reinfection) by preventing access to birds, rodents, uncooked meat, and unpasteurized dairy products. Food preparation areas can be infectious to cats! If pregnant (or trying to get pregnant) avoid handling free-roaming cats as their fur or paws may be contaminated; this also means keeping indoor-outdoor cats off of bedding, pillows and kitchen counters. Avoid cuddling a cat with diarrhea or bowel incontinence or one which has an illness which might reactivate tissue cysts.



Infected cats can transfer the tuberculosis causing mycobacteria to humans. It is particularly dangerous to humans with poor immune systems. Since there is no effective treatment for cats to lessen the risk to humans, veterinarians recommend euthanasia for these cats. Tuberculosis is rare in cats.


Most viruses are species specific. Feline Immunodeficiency Virus ("FIV"), Feline Infectious Peritonitis ("FIP"), and Feline Leukemia Virus ("FeLV") cannot cause illness in people. A cat cannot catch a human common cold, although there is indication that canine coronavirus may potentiate FIP in cats and human influenza can infect cats. As well as rabies, there are a few feline viral infections which can cause illness in humans.

Rotaviruses cause diarrhea in many species; the infection is usually temporary and treatable with diarrhea medications. Rotaviruses can cross species; sick cats are not infectious to humans. However, when cleaning up diarrhea and disinfecting affected areas (litter boxes, floors, carpets), it is advisable to wear rubber gloves as a precaution.


Cats can transfer certain parasites to humans. Fleas are the most common and cause itchy, sometimes inflamed, spots. Some people are more prone to fleabites than others and some people react worse than others. Humans may pick up a tick in long grass that has fallen off its former host. Ticks on a cat stays there until it is engorged or until removal by the owner or veterinarian

Transfer of some feline intestinal parasites to humans is possible. Roundworm eggs infect humans, particularly children, through a fecal to oral route. Tapeworm eggs are not directly infectious to people.

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