Clinical Disease and Diagnostics

Publisher Summary The term T. gondii infection describes the asymptomatic course of infection observed in the majority of infected immunocompetent individuals. In contrast, toxoplasmosis describes the symptomatic course of infection with T. gondii. T. gondii infection and toxoplasmosis are discussed in the chapter in the setting of immunocompetent and immunocompromised patients. Acute acquired infection in immunocompetent individuals most often manifests as asymptomatic diseases. Only a minority of individuals acutely infected with T. gondii present with signs or symptoms of the infection. The symptoms vary from a short, self limiting, unspecific illness, to severe symptoms with prolonged fever, fatigue, and retinochoroiditis. Cervical lymphadenopathy is the most common clinical presentation; lymph nodes are discrete and non-tender, and measure only a few centimeters in diameter. Rare manifestations of toxoplasmosis in apparently immunocompetent individuals include pneumonitis, hepatitis, myocarditis, polymyositis, and fever of unknown origin. Toxoplasma retinochoroiditis may be the result of postnatally or congenitally acquired infection. Involvement of the eye occurs during the acute stage of infection, and reactivation is observed during the latent stage of the infection.