Toxoplasmosis

Definition:

A common infection with the protozoan intracellular parasite Toxoplasma gondii.

Causes, incidence, and risk factors:

Toxoplasmosis is found in humans worldwide and in many species of animals and birds. The cat is the definitive host of the parasite. Human infection results from ingestion of contaminated soil, careless handling of cat litter, ingestion of raw or undercooked meat, or transmission from a mother to a fetus through the placenta (congenital infection). Over 80% of primary infections produce no symptoms, but the incubation period for symptoms is 1 to 2 weeks.

Congenital toxoplasmosis is caused by infection with Toxoplasma gondii in a pregnant woman, with up to 50% of such infections transmitted to the fetus. Signs of congenital infection may be present at birth or develop over the first few months of life. Infants may show signs of central nervous system disorders, enlargement of the liver and spleen, blindness, and mental retardation. Toxoplasmosis also affects people who are immunosuppressed (AIDS, cancer , or patients on immunosuppressive therapies). The disease may affect the brain, lung, heart, eyes, or liver.

Update Date: 02/09/00
Updated by: J. Gordon Lambert, MD, Associate Medical Director, Utah Health Informatics and adam.com editorial