[Problems of congenital toxoplasmosis. Evolution over four decades]

Abstract

EFFECT OF PREVENTIVE MEASURES: The development of reliable routine serology tests and the demonstration of the high prevalence of toxoplasmosis in France led to mandatory prospective screening of pregnant women in 1978, followed by prenatal screening in 1985. In addition, in utero diagnosis, first on fetal blood and now with the reliable and safe method using polymerase chain reaction on amniotic fluid, formally identifies the parasite. THE SITUATION TODAY: A comparison of the experience of a specialized center in Paris during three different periods over the last 40 years showed that currently 71% of all cases of congenital toxoplasmosis are infraclinical at birth and only 5% are severe. Mean incidence of seroconversion during pregnancy is 1.48%, with a 40% risk of fetal contamination if no treatment is given. The risk of overt fetopathy predominantly concerns maternal infections occurring prior to 26 weeks gestation. IN UTERO TREATMENT: Positive PCR diagnosis on amniotic fluid imposes serial ultrasound examinations to identify any fetopathy and an in utero treatment by giving the mother the pyrimethamine-sulfadiazine combination. Biological results are favorable. POST-NATAL TREATMENT: Post-natal treatment is indicated even in latent forms and should be continued for the first year of life. The pyrimethamine-sulfadiazine combination is the only pharmaceutical regimen with well-proven efficacy. New compounds should allow better prophylaxis against maternofetal contamination or improved post-natal treatment. RECURRENCE: In 70% of the cases, serology tests become positive again, but are not associated with significantly increased risk of ocular recurrence.