Toxoplasmosis

Abstract

Toxoplasma gondii is an obligate intracellular parasite capable of infecting humans and a variety of other warm-blooded animals. The organism is distributed widely in nature and may infect as many as 1 of 3 persons worldwide. Most Toxoplasma infections are either asymptomatic or otherwise benign; notable exceptions include the infections of the developing fetus whose mother acquires an acute T gondii infection during gestation and of immunosuppressed patients, such as those with the acquired immunodeficiency syndrome (AIDS), in whom the illness may be severe or even fatal. The cat and other felines (such as the lynx) appear to be the only definitive hosts for this protozoan. The name Toxoplasma is derived from the Greek word toxon (meaning arc or bow) and is a reference to the shape of the organism. The gondi is a North African desert rodent related to the gerbil in whose splenic and hepatic mononuclear cells the parasite was observed initially. This article briefly reviews the biology of T gondii and its epidemiology in man and other animals, as well as its pathogenesis, clinical manifestations, methods for accurate diagnosis, and preventive strategies. Information on prenatal diagnosis and treatment modalities is emphasized. THE ORGANISM T gondii is a protozoan parasite that exists in three developmental stages: tachyzoite, tissue cyst, and oocyst.