[Congenital toxoplasmosis with delayed immune response].

In typical cases the diagnosis "toxoplasmosis connata" is based on clinical symptoms and positive serological findings. When the infection of the fetus occurred a short time before birth the neonate seems still normal and the disease develops in the postnatal period. In such cases the specific antibody production may be delayed. We present a case report with well documented first infection of the mother between the 15th and 30th gestational week but with no specific treatment. The baby was born without clinical signs of a toxoplasmosis infection and developed the disease 2-3 weeks later; the serological test (complement fixation test, KBR) was negative at the 24th postnatal day. Specific antimicrobial therapy could be started after serological conversion between the 4th and 5th postnatal week. Problems of diagnostics and delayed therapy are discussed.