Feline zoonosis

A feline zoonosis is any infection—caused by viruses, bacteria, fungi, protozoa, nematodes, or arthropods—that can pass from a domestic cat (*Felis catus*) to a human. Some of these diseases are newly emerging or making a comeback. Infected cats may show symptoms (which can differ from human symptoms) or may appear perfectly healthy. People who spend a lot of time around cats are at higher risk, but even those without pet cats can catch these infections through contact with cat feces or parasites that have left the cat’s body.

People can get infected through bites, scratches, or direct skin or mucous membrane contact with a cat—including kissing the animal or letting it lick the mouth or nose. Mucous membranes are especially vulnerable if the pathogen is in the cat’s mouth. Contact with saliva, urine, or other body fluids or secretions also poses a risk, as does accidentally swallowing fecal material. Inhaling droplets or aerosols coughed up by a cat is another route of infection.

In the United States, about 32% of homes have at least one cat. Some contagious infections, like campylobacteriosis and salmonellosis, cause visible symptoms in cats. Others, such as cat scratch disease and toxoplasmosis, show no signs and are carried by cats that seem healthy.

**Cats as vectors** Some disease-carrying arthropods use cats as carriers. Fleas and ticks can transmit pathogens that cause Lyme disease, tick-borne encephalitis, and Rocky Mountain spotted fever in people.

**Bites** Cat bites are a common source of animal bite injuries and can transmit serious diseases like rabies. They often lead to bacterial infections—up to 80% of cat bites become infected, in part because a cat's sharp teeth can drive bacteria deep into the tissue.

**Viral** By 2010, more than 400 cases of cowpox had been reported from cats to humans. Symptoms differ between species: in people, a local rash appears on the arms and face, and the infection usually resolves on its own, but in immunosuppressed individuals it can progress to a systemic illness resembling smallpox, which can be fatal. In cats, signs include multiple skin sores on the paws, neck, head, and mouth, a purulent eye discharge, and sometimes necrotizing pneumonia. In the United Kingdom, about 50% of human cowpox cases are linked to cats.