Biological post-natal diagnosis of congenital toxoplasmosis

Specific postnatal diagnosis of CT is crucial in two cases: (i) when clinical signs occur within the first 6 months of life, and no information on the mother’s antenatal serostatus is available, and (ii) seroconversion is diagnosed during pregnancy, with or without antenatal diagnosis of CT. The first situation is mainly observed in countries where maternal screening is inexistent [1]. In countries where maternal screening is obligatory (France and Austria) or is done on a regular basis by obstetricians (Belgium, Switzerland, Italy), the slightest suspicion of maternal toxoplasmosis calls for parasitological and immunological testing at birth and during the first year of life [2, 3]. Parasitological and immunological diagnosis of congenital toxoplasmosis is simpler post-natally than in utero, owing to the better accessibility of appropriate samples (cord blood, placenta, serum, etc.). However, CT is mainly sub-clinical, especially in countries with effective screening programs, where treatment of the fetus reduces the risk of major complications [2, 4–6].