Keeping Pets and People Healthy : Toxoplasmosis, Salmonellosis, Ringworm

by Food and Drug Administration (FDA)

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Toxoplasmosis

Cats may be carriers of Toxoplasma gondii, a parasite causing the disease toxoplasmosis. Direct contact with cat feces is one possible route of human infection, but toxoplasmosis is more likely to spread to people through eating raw or undercooked meat. Food animals may become infected by grazing in fields or eating feed contaminated with cat feces. People can also get toxoplasmosis from gardening and accidentally ingesting soil where an infected cat has defecated. Wearing gloves while gardening and washing hands afterward are recommended.

Cats pick up the toxoplasma parasite by eating rodents, birds or other prey, undercooked meat, the feces of infected cats, or contaminated soil. Most cats infected with Toxoplasma don't show signs and don't need to be treated, but those that do get sick may be diagnosed with laboratory tests and treated with medications. The CDC estimates that more than 60 million people in the United States probably carry the toxoplasma parasite, but few become ill from it. Those who get sick may have flu-like symptoms such as swollen glands and muscle aches.

Pregnant women with cats in the household need to take special precautions because toxoplasmosis can cause miscarriage, premature births and birth defects.

Pregnant women and others with suppressed immune systems should avoid changing a cat's litter box or, at a minimum, wear disposable gloves and wash their hands thoroughly afterward, says the CDC. Changing the box daily is recommended because it takes the toxoplasma parasite at least 24 hours to become infectious. It's also possible to become infected by inhaling the dried feces, so seal the waste in a plastic garbage bag for disposal. Cover children's sandboxes when not in use to prevent contamination from cat feces.

Antimicrobial drugs are available to treat people who become infected with toxoplasmosis.

Salmonellosis

Salmonellosis is a disease caused by the bacterium Salmonella. People usually get salmonellosis by eating contaminated food, such as undercooked meats or eggs. But Salmonella can also be transmitted to people through pets, particularly reptiles, baby chicks, and ducklings, which commonly pass the organism in their feces.

Most, if not all, reptiles carry some Salmonella in their intestinal tract, says Scott Stahl, D.V.M., owner of Stahl Exotic Animal Veterinary Services in Vienna, Va., and past president of the Association of Reptilian and Amphibian Veterinarians. Stahl says he and other reptile veterinarians have stopped testing the animals for Salmonella. "They tend to intermittently shed the organism, so a fecal culture may be a false negative," he says, giving the reptile owner a false sense of security. Once the bacteria are shed in droppings, Salmonella may be found on the reptile's skin, its cage, the floor, and any other surface the animal touches.

Since Salmonella are part of a reptile's normal bacteria and cannot be eliminated from its intestinal tract, people need to practice good hygiene around reptiles. Stahl advises no eating, drinking, or smoking around the animals. Nor should the pets be allowed to roam freely through the house, especially in areas where food is prepared or eaten. Always wash your hands with hot, soapy water after handling reptiles, their cages or equipment, and any surfaces they come into contact with.

The CDC estimates that 70,000 people in the United States get salmonellosis each year from contact with reptiles. Reptiles are not appropriate pets for small children and should not be in the same house as an infant, advises the CDC.

Ringworm

Ringworm is not caused by worms, but by several different types of fungi. People can get this skin and scalp disease just by touching the skin or fur of an infected animal, typically a cat, which holds the fungal spores. Ringworm can also infect dogs, ferrets, horses, rabbits, guinea pigs and other animals.

Signs of the disease can be "virtually invisible" in some cats and dogs, says Wilmot, but they can still transmit the disease to people. Others will lose patches of fur or hair, exposing bare skin with a lesion that is sometimes ring-like and itchy. Ringworm in people may show itself as a ring-shaped, reddish, itchy rash that can be dry and scaly or wet and crusty.

Keeping animal areas clean will help prevent ringworm, since the disease-causing fungi grow in dirt and contaminated bedding. In addition to contracting it from animals, people can also get ringworm from contact with other infected people or their personal items.

Topical and oral medications may be used to treat ringworm in people and pets.

Cat-Scratch Disease

The CDC estimates that more than 20,000 people in the United States get cat-scratch disease (CSD) each year. Most cat scratches don't develop into CSD, but those that do may cause fever, fatigue, headache and swollen lymph glands.

The bacteria believed to cause CSD may be transmitted by fleas. About 40 percent of cats carry the infectious bacteria at some time in their lives, according to the CDC. Many do not show signs of illness, but some develop fever, lethargy, swollen lymph glands, inflamed eyes and gums, and neurological disease, requiring treatment by a veterinarian. Cat owners should use a good flea control, keep cats' claws trimmed short, and discourage rough play to prevent scratches and bites. If you are bitten or scratched, wash the area immediately with soap and water. Do not let cats — or any animal — lick open wounds on your body.

About the Author

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FDA is A United States government body that oversees medical devices, including contact lenses, intraocular lenses, excimer lasers and eyedrops. In the US, these products must be approved by the FDA before they can be marketed.