Toxoplasma gondii is a widespread zoonotic protozoan. Its host range includes a variety of birds and most mammals. Felids are the definitive hosts for this organism, and are the only animals that pass oocysts in their feces. Other hosts develop infective tissue cysts. Most feline infections occur postnatally through ingestion of infective tissue cysts, or rarely oocysts, although congenital infections can occur. Feline infections are typically asymptomatic. Among symptomatic infections, congenitallyinfected kittens are the most severely affected (1). For humans, T. gondii infection can cause severe neurologic or ocular disease in the fetus if acquired during pregnancy. In general, humans usually acquire their infection (a) from ingestion of oocyst-contaminated soil or water; (b) from tissue cysts in undercooked meat; or (c) congenitally (1). Most people infected after birth are asymptomatic, however a minority may develop fever, malaise, and lymphadenopathy. In rare cases, postnatally infected humans may develop ocular complications (e.g., retinochoroiditis). Toxoplasmic encephalitis, pulmonitis, or other systemic disease may be seen in patients with immunosuppressive disorders.
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