Prevention of congenital toxoplasmosis in France. Evaluation of risks. Results and prospects of prenatal screening and new-born follow-up

In France, a national program for the prevention of congenital toxoplasmosi s has been set up 25 years ago. This program is here presented and discusse d in details. It is based on a decision tree it-ell defined, with pre and/o r per gravidic serological screening with several different tests, complete d, if necessary, by ultrasounds examinations of the fetus, biomolecular tes ts (PCR) oil amniotic fluid, and by clinical, biological, and radiological surveillance of neo-nates. The purpose of this prevention programm is to : 11 identify nonimmune Young women and limit their contamination risk during pregnancy by appropriate counseling on hygiene and diet; 21 screen and tre at per gravidic toxoplasmosis as early as possible so as to prevent or limi t transmission to the fetus and its consequences. 3 / in utero diagnose and treat infestation of the fetus; 4/diagnose and treat asymptomatic Congenit al toxoplasmosis in neonates, to prevent risks of reactivation and late com plications, especially ocular. Stich a prevention program has a cost valida ted by the prevalence of acquired toxoplasmosis in adults in France (over 5 0 % of the population) and by the yearly incidence of congenital toxoplasmo sis (at least 0.1 % of births according to the best hypothesis). These 6 to 700 congenital toxoplasmosis cases per year may be compared to the 6 to 7 000 per gravidic seroconversions which could lead to fetal contamination if no preventive measures are taken. Nevertheless, as it is often the case in the field of prevention, it is very difficult to statistically assess the efficacy of this program ei-en though several arguments show that it allows to eliminate the most serious toxoplasmosis, sources of serious handicaps at birth, and to limit the frequency of late complications (especially reti no-choroiditis) of asymptomatic infections in neonates. The position of Eur opean countries varies as to prevention of congenital toxoplasmosis. Some c ountries (Austria, Belgium) haw national prevention programs similar to the French one, whereas others haw set zip only limited programs or set lip no systematic prevention. These differences may be accounted for by the diffe rent frequencies of toxoplasmic risk. It seems mandatory to forget all dogm atism and not to stick to a strictly statistical approach for a disease wit h not only, medical but also social and human consequences.