Cat Infections That Can Spread to Humans

Cat sleeping on bed at owner's feet

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We share a lot of things with our cats—our homes, our food, sometimes our beds. There's more than that. Many infections come from cat bites and scratches but many don't even need a nip. Here are some infections that your cat can share.

Ringworm

Cats get ringworm (dermatophysis)—the fungus (not a worm at all)—that causes scaly patches on our skin, often red and ring-like. This is the most common infection veterinarians acquire from animals. Cats more than dogs spread ringworm. Cats who are infected are usually kittens or older cats, sick, long-haired or live with multiple other cats. They may have the same scaly skin. A child picking up a kitten with a patch of scaly skin can easily catch ringworm.

Salmonella: Typhoid Kitty?

Cats don't get typhoid, a type of salmonella, but they do get salmonella. Salmonella can cause diarrhea, abdominal pain, fevers, and other symptoms in humans. There was an outbreak of salmonella in humans associated with dry cat (and dog) food. Young children were affected in homes where cats and dogs were fed in the kitchen. Cat food, just like human food, can spread food-borne illness; they usually contain meat. Cats are thought to possibly get salmonella from the birds they catch. Cats may not have any symptoms from salmonella like diarrhea; handlers may not realize the risk. Likewise, there are other diarrheal diseases cats and their kitty litters can carry without anyone knowing: campylobacter, giardia, and cryptosporidium. It's important to be careful with kitty litters.

Toxoplasmosis

Cats spread Toxoplasmosis because they are an intrinsic part of the parasite's lifecycle. Usually, cats themselves do not directly infect us. They shed Toxoplasma gondii in their kitty litters when infected (often transiently as kittens). The infection can be spread by eating without washing after cleaning the kitty litter. The infection normally though spreads through infected meats or drinking water and through vegetables, where dirt contaminated by cat droppings is not washed off. The infection is usually self-limited. It may feel like the flu and cause swollen glands. In some, it can cause long-term blurry vision and eye pain. If it is newly acquired in pregnancy, it can cause serious birth defects. It can be a terrible disease in the immunocompromised, especially AIDS patients, who can develop brain infections. It is thought that the infection is associated with psychological effects in humans.

Q fever

Q fever is a rare infection; in 2017, 153 acute Q fever cases were reported in the United States, as well as 40 chronic Q fever cases. Transmission can occur when an infected mother cat is giving birth, when the bacteria, Coxiella burnetii, can be breathed in with dust in the air. The infection can be serious: high fevers, severe headaches, body aches, abdominal pain. It can cause pneumonia and heart valve infections in rare cases. Possibly half of those infected do not have any symptoms.

Influenza

You sneeze. Your cat sneezes. There's a tiny, tiny chance your cat got what you got but usually, cats do not become sick with the flu like we do. One Ohio study showed that 62% of 400 tested domestic cats showed signs of past flu. The H1N1 pandemic infected 30% of domestic cats that were studied in Northern China. There may be more transmission between cats and birds with new strains than we think. This, however, has not been shown to have any real effects on cat owners.

Toxocara

A cat may think the backyard is a kitty litter. As a result, Toxocara worm eggs (Toxocara cati) may be released into the soil. Humans—especially children—may accidentally put their hands in their mouths after touching this dirt. Perhaps 1 in 4 cats carry this infection. Most people exposed have no symptoms. When they do, they can have Visceral Larva Migrans, where worms spread internally (and also cause high eosinophil blood cell levels). It can also cause Visceral Ocular Migrans with vision loss and eye damage.

Tuberculosis: Kitty TB 

This is very, very rare. In 2014, 2 people in England developed active Tuberculosis (Mycobacterium bovis) and 2 latent TB (no active disease, at risk for developing disease) from cats. This is not Mycobacterium tuberculosis, which causes almost all TB in the US. Mycobacterium bovis is an infection associated with cows and is one reason why milk is pasteurized.

A Word From Verywell

Some cat diseases have names similar to human diseases but do not cause human disease. Feline Immunodeficiency Virus (FIV) and Feline Leukemia Virus (FeLV) sound like human diseases but are not.

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