Pet doctor: Watch for diseases you can catch from your cat

We all love our cats, but it is important to be cognizant of potential zoonotic disease risk, and how to minimize it. Like dogs, cats can carry rabies, so it is very important that all cats are up to date on rabies vaccinations.

Ringworm and other skin parasites

Ringworm is not a worm, but a skin infection you can catch from your cat. It is named for the circular rashes it often causes on the scalp of young children. Microsporum canis is a fungal organism that commonly infects the skin of cats, and it causes areas of hair loss and thinning. Close to 50 percent of humans exposed to cats with ringworm will develop a scaly, itchy, circular rash on their skin, which is more common in young children, the elderly and people with inadequate immune systems, such as those infected with HIV. If you have cats in your household, and anyone in your family develops a skin rash, ringworm should be on the list of possible causes. Most cases respond well to medication lotions or ointments.

Strategy for prevention: Have any area of hair loss on your cat examined by a veterinarian, and seek medical attention for any members of your cat-owning household who develop a skin rash. Keep your cat inside to minimize the risk of skin parasites.

Toxoplasmosis

Some cats shed a potentially infectious organism in their feces that can be particularly dangerous for pregnant women and other humans with a compromised immune system. Toxoplasmosis is a parasite that can survive in the environment for long periods of time, where it might be ingested by children playing in a sandbox, or an adult working in the garden. It creates a risk for humans only when the infected spores are ingested, so actual cases of infection in humans are infrequent. Pregnant women that get infected can potentially transmit serious birth deformities to their developing fetus, such as spina bifida, a flaw in the development of the spinal cord.

Strategy for prevention: Keep sandboxes covered to keep out neighborhood cats, and pregnant women should avoid cleaning litter boxes.

Note: There is no evidence or recommendation that pregnant women or HIV-infected individuals should give up their cats.

Cat scratch fever and bite wound infections

A cat scratch is painful enough, but it can also cause debilitating disease in people, especially those with a compromised immune system. People with AIDS and those receiving drugs to prevent organ rejection after transplantation are especially susceptible. Affected humans may have swollen lymph nodes, fever and malaise up to three weeks after they are scratched. The organism responsible for the infection, Bartonella, is usually carried by fleas that live on the cat, but most cats do not show any sign of illness.

Bite wounds from cats tend to cause more severe infections than those of dogs, so anyone bitten by a cat should seek prompt medical treatment. Because of the small size of the punctures, it is difficult to thoroughly clean out such a wound, and antibiotics are often necessary to prevent serious infection.

Strategy for prevention: Promptly wash and disinfect any cat scratches, especially if you live in an area where fleas are common. Seek immediate medical attention for cat bite wounds. Trim your cat’s claws or apply a protective covering such as Soft Claws.

Although it may appear that pet ownership may be fraught with the medical risk, it turns out that most pets and their owners live healthy lives with minimal incidence of zoonotic disease. Pet owners more at risk include the elderly, the very young, and the immuno-compromised (i.e. AIDS patients and organ transplant recipients).

Recent reports of possible transmission of MRSA (methycillin-resistant staphylococcus aureus), an extremely drug-resistant bug, between people and their pets have raised concern that this will become an increasing problem. Humans may acquire an MSRA infection from a hospital stay, then pass it along to their pets, where it may live for several months before being passed back to humans that have close contact with the pet. Dogs and cats both appear to be potential recipients and carriers of the infection, which can cause severe skin infections and pneumonia. Increased emphasis on hand-washing after handling pets and using caution around open wounds is currently being advised, and in general terms, is the best strategy to minimize risk of zoonotic disease.

Jon Geller is a veterinarian at the Fort Collins Veterinary Emergency and Rehabilitation Clinic.