Toxoplasmosis is an
infection that is caused by the protozoan
parasite Toxoplasma gondii. The
parasite is carried by cats, birds and other animals and is found in soil contaminated by cat feces and in meat, particularly pork. The
parasite can infect the lungs,
retina of the eye, heart,
pancreas, liver, colon and testes. Once T. gondii invades the body, it remains there, but the
immune system in a healthy person usually prevents the
parasite from causing disease. If the
immune system becomes severely damaged, as in people with
AIDS, or is suppressed by drugs, T. gondii can begin to multiply and cause severe disease. The most common site of toxoplasmosis is the brain. When T. gondii invades the brain, causing inflammation, the condition is called toxoplasmic
encephalitis. While the disease can occur in persons with healthy immune systems, it can normally be cured successfully. See also
Protozoa.