Toxoplasmosis is caused by a parasite of cats called Toxoplasma gondii. Cats become infected when they eat mice or other small animals that have the Toxoplasma cysts in their tissues. Infected cats shed Toxoplasma eggs in their feces. People can become infected if they ingest Toxoplasma eggs, either directly after handling cat feces, through food contaminated by cat feces, or eating meat (chiefly pork) that carries Toxoplasma cysts. Healthy adults generally have few or no symptoms as a result of infection with Toxoplasma. However, serious illness can occur in persons with weakened immune systems and pregnant women. Women who become infected early in pregnancy risk birth defects or death of their developing fetus.
Toxoplasmosis can be prevented by washing hands well with soap and warm water after cleaning a cat’s litter box or handling soil that might be contaminated with cat feces (e.g., while gardening). Although rarelyfound in commercial meat in the United States, all meats, regardless of source, should be cooked thoroughly before being eaten. To reduce Toxoplasma infection in cats, cat owners should not feed raw or undercooked meat to their cat and should discouraged it from hunting.