Toxoplasma gondii: The model apicomplexan. Perspectives and methods

Toxoplasmosis is caused by a one-celled protozoan parasite known as Toxoplasma gondii. In the United States, it is estimated that approximately 30% of cats, the primary carriers, have been infected by T. gondii. Most humans contract toxoplasmosis by eating cyst-contaminated raw or undercooked meat, vegetables, or milk products or when they come into contact with the T. gondii eggs from cat feaces while cleaning a cat's litterbox, gardening, or playing in a sandbox. Approx 1 in 4 (more than 60 million) people in the USA are infected with the parasite, and in the UK between 0.5 and 1% of individuals become infected each year. By the age of 50, 40% of people test positive for the parasite. The predilection of this parasite is for the central nervous system (CNS) causing behavioral and personality alterations as well as fatal necrotizing encephalitis, and is especially dangerous for HIV infected patients.