Congenital acquired immunodeficiency syndrome and congenital toxoplasmosis: pathologic support for a chronology of events.

We report a case of congenital acquired immunodeficiency syndrome (AIDS) with congenital opportunistic toxoplasmosis. The thymic histopathology was that seen in childhood AIDS cases and not that seen in primary congenital toxoplasmosis. The toxoplasma infection was selectively localized to the brain and the serum titers were paradoxically low as reported in most adult cases of AIDS with secondary infection by the parasite. These findings strongly suggest that the infection by the human immunodeficiency virus (HIV) preceded the toxoplasma infection in the fetus.