Management of congenital toxoplasmosis in France: current data

Congenital toxoplasmosis is caused by transplacental contamination of the fetus withToxoplasma gondiifollowing maternal primary infection. The risk of mother-to-child transmission depends on the term of pregnancy at the time of maternal infection. The risk is lower than 5% in the first trimester but can reach 90% in the last days of pregnancy. Inversely, however, fetal disease is more severe when contamination occurs early in pregnancy. The French prevention program officially recommends monthly serological screening of susceptible women during pregnancy and information about hygiene and dietary rules. Prenatal diagnosis of congenital toxoplasmosis is based on a combination of examinations: PCR testing for the parasite in amniotic fluid, mouse inoculation, fetal ultrasonography, and magnetic resonance imaging. Neonatal screening consists of PCR of the placenta, mouse inoculation, detection of specific IgM and IgA in the newborn, ocular fundus examinations by indirect ophthalmoscopy, and transfontanellar ultrasonography. As soon as maternal infection is suspected, preventive treatment with spiramycin begins; the treatment is changed to a combination of pyrimethamine-sulfonamide if fetal infection is proved. Some teams are using this combination as first-line treatment after 30 weeks of gestation, without performing amniocentesis. Recent European multicenter studies raise questions about the effectiveness of prenatal treatment on mother-to-child transmission and on the reduction in the number and severity of fetal sequelae. A randomized controlled trial is required to prove the efficacy of prenatal treatment in general and of specific drugs, in particular. As soon as infection is confirmed, infected children are treated with the pyrimethamine-sulfonamide combination for 12 to 24 months. Recent multicenter studies show that postnatal treatment does not prevent ocular lesions: 5% of treated children had choroiditis lesions at birth, 20% at 5 years, and 30% at 8 years of age. Furthermore no consensus exists about the duration of postnatal treatment (3 months in Denmark versus 12 months in France). A multicenter randomized controlled trial is necessary to assess the efficacy of postnatal treatment and determine its duration. A surveillance system was set up in 2007 by the National Reference Center for Toxoplasmosis to determine the perinatal burden of this infection and to assess the national policy.