Toxoplasmosis is the name of the disease that is caused when an animal or person is infected with the microscopic parasite Toxoplasma gondii. Cats are central to the disease's transmission. Most cats are exposed when they eat infected prey items or while they are still developing in their mother's uterus. These cats can then shed the organism in their feces and expose people, pets, and farm animals. If a pregnant woman becomes infected with Toxoplasma for the first time during pregnancy, birth defects or miscarriages may result. It must be remembered, however, that people are much more likely to be exposed to this parasite by eating raw or undercooked meat or through contact with contaminated soil.
Many pets that are exposed to Toxoplasma do not show any symptoms or develop only a mild illness that goes unnoticed by their owners. Healthy adult animals are quite resistant to the disease, but young or immunosuppressed cats and dogs can develop potentially life-threatening problems as a result of toxoplasma infections. Clinical signs of toxoplasmosis depend on where the infection localizes in the body. A veterinarian can send a sample of a pet's blood to the lab to be tested for exposure to toxoplasma, but in many cases the clinical relevance of a positive test result is not clear.
Treatment for toxoplasmosis in cats and dogs is rarely necessary, but if persistent symptoms develop some types of antibiotics can be helpful, although they will rarely completely eliminate the infection. Pregnant cat owners can protect themselves from toxoplasmosis by having some one else clean litter boxes or by scooping out the feces once or twice daily, which does not give the microorganism the time it needs to develop into the stage that is capable of causing a new infection. Most cases of toxoplasmosis in people can be prevented if gloves are worn while handling soil, all meat is thoroughly cooked, and hands are washed well after handling items that are potentially contaminated.
Written by: Jennifer Coates, DVM
Last reviewed: October 2, 2008