Toxoplasmosis in pregnancy in an area with low seroprevalence: is prenatal screening still worthwhile?

BACKGROUND: The effectiveness of Toxoplasma gondii (Tg) screening during pregnancy in areas with a low prevalence of the infection is debated. We investigate the Tg serological status, the rate of primary infection in a cohort of pregnant women and the rate of congenital toxoplasmosis among their infants during a 3-year period in an urban area with low Tg prevalence.

METHODS: Demographic and Tg serological data for all pregnant women delivering from January 2009 to December 2011 were collected. All pregnant women with primary Tg infection during pregnancy and their infants were included in the study.

RESULTS: In early pregnancy, 10,347 women underwent prenatal screening and 2308 (22.3%) had anti-Tg. The seroprevalence among non-native women was significantly higher than that among native women [32.8% vs. 19.1%, relative risk: 1.71, P < 0.001]. The incidence rate of primary Tg infection during pregnancy was 0.77%. Immigrant women were more likely to be infected during pregnancy than Italian women (relative risk: 4.88, P < 0.001). Tg infection was more frequent in women coming from Africa, Asia, Eastern Europe and South America. The CT incidence rate was 0.06%. All congenitally infected infants were born to immigrant mothers.

CONCLUSIONS: Tg infection during pregnancy and congenital disease are more frequent in non-native mothers and their infants. Measures to prevent Tg exposition must be carefully explained to pregnant women, with a focus on specific habits in non-native women. Prenatal screening is still effective to select women for prenatal therapy aiming to decrease vertical transmission and to identify foetuses/newborns with congenital disease that could benefit from pre/postnatal antiparasitic therapy.