Congenital toxoplasmosis: chances of occurrence in subsequent siblings.

Occurrence of congenital toxoplasmosis in subsequent siblings after the birth of an affected child is discussed. Toxoplasmic retinochoroiditis was found in 3 surviving siblings. The diagnosis was made by the typical fundus lesions in children, intracranial calcification in one child, and significant positive titer for toxoplasmic antibodies in all the children and the mother, who was asymptomatic. Serology for syphilis, skin tests for histoplasmosis and tuberculosis, blood studies with sedimentation rate, and chest roentgenograms were all negative in mother and all 3 children. The view that transmission of infection from mother to the fetus may result from a chronically infested uterine wall is supported and is thought to be the probable cause in the cases reported here. After the birth of one child with congenital toxoplasmosis, the parents may be reassured about the favorable prognosis of subsequent pregnancies with some reservation. However, it appears unwise to categorically refute the repetition of congenital toxoplasmosis in siblings. It is also suggested that because of possible danger of reactivation, the healed toxoplasmic chorioretinal lesions should be properly monitored if the patient is to be given corticosteroids for any other reason.