Toxoplasma gondii tachyzoites
Courtesy of DPDx


Toxoplasma gondii is a ubiquitous protozoan parasite found in a wide variety of hosts, including much of the human population. It is a blood and tissue dwelling protozoan (subphylum Apicomplexa) and can take up residence in several different tissue types. The tachyzoite form is crescent shaped, 2-3 μm wide and 5-7 μm long, and is usually found in intracellular clusters of 8 to 32 parasites. Transmission occurs primarily through ingestion of oocysts in contaminated meat or by contact with feces from infected cats. Although infection in humans is usually asymptomatic or accompanied by mild generalized symptoms, in certain clinical contexts toxoplasmosis can be a dangerous and potentially fatal disease. Such cases include toxoplasmosis encephalitis in immunocompromised patients and congenitally acquired toxoplasmosis.




Christopher Nguyen, 2007,
Stanford University
Parasites and Pestilence: Infectious Public Health Challenges
Professor D. Scott Smith,

Last Update: 24 May 2006