Congenital toxoplasmosis: efficacy of maternal treatment with spiramycin alone

The evidence supporting an additional benefit of a combined regimen of pyrimethamine-sulfonamides compared with spiramycin alone in the secondary prevention of congenital toxoplasmosis was critically evaluated.

We reviewed the series of cases published in the English literature on antiparasitic treatment of acute toxoplasmosis infection in pregnancy, using spiramycin until fetal infection is documented, then using cycles of spiramycin alternated with combined pyrimethamine-sulfonamide therapy. We then compared the occurrence of overt disease among infected offspring (both severe, represented by ophthalmologic or cerebral abnormalities, and mild occurrences, represented by asymptomatic intracranial calcifications and retinal scars without visual impairment) between the published case series and our consecutive series of cases treated during a 10-year period (January 1986-December 1995) with spiramycin alone.

The prevalence of fetal infection in our series was 7.8% (12/154), similar to that reported after alternated regimens (7.0%). The rate of overt disease among infected fetuses is not different after treatment with alternated regimens than after continuous antibiotic spiramycin therapy [23% (19/82) vs. 10% (1/10); relative risk, 2.3; 95% confidence interval, 0.4, 47.0]. The pharmacokinetics of the drugs used may account for this finding.

The treatment of acute toxoplasmosis in pregnancy with an alternated antibiotic regimen of pyrimethamine-sulfonamide is not more efficacious at preventing overt neonatal disease than treatment with continuous spiramycin alone.