A primary infection during early pregnancy may lead to fetal infection with death of the fetus or fetal brain damage. Later in pregnancy, maternal infection results in mild or subclinical fetal disease with delayed manifestations, such as inflammation of the retina.

Among immunodeficient individuals, primary or reactivated infection may cause swelling of the brain, inflammation of the retina, pneumonia, generalized skeletal muscle involvement, myocarditis, a maculopapular rash and/or death. Cerebral toxoplasmosis is a frequent component of AIDS.