Prevalence of toxoplasmosis in France in 1998: is there a difference between men and women? At what age do children become infected?
The only national seroprevalence data currently available on toxoplasmosis in France are from the national perinatal surveys of pregnant women conducted in 1995 and 2003. These surveys are national, exhaustive and cross-sectional studies of all pregnant women who give birth in France during one specified week. These cross-sectional studies, conducted among women of childbearing age (defined as 18 to 45 years), showed a positive correlation between seroprevalence and age, with a significant regional disparity. This study was performed in order to compare the prevalence of toxoplasmosis antibodies in men and women in the 18-45 age group, to confirm regional variations and to estimate the seroprevalence of toxoplasmosis in France for different age groups, particularly among children and among adults aged over 45 years. Serum samples from 2060 subjects were available from a national serum bank that was established in 1997 as part of a European study on vaccine preventable diseases. The sera were tested for IgG antibodies in 2008-2009, by ELISA test, at the laboratory of parasitology-mycology, CHU Grenoble. The seroprevalence for the population aged 1-64 years was 55.4%. Seroprevalence did not vary between the sexes, except among those aged over 45 years, where it was higher in men than in women. Toxoplasmosis seroprevalence varied significantly by regions for all ages. It increased with age and we noted a stronger increase in prevalence in adolescents (10-20 years) than in other age groups. This study showed that children have limited exposure to Toxoplasma gondii and that seroprevalence in men and women does not differ for the population aged 45 years and under. This study confirms the geographical disparity in prevalence in France that has been found in other studies in women of childbearing age. This disparity cannot be explained by different laboratory techniques, because sera were tested in a single laboratory. The study also raises the possibility of extrapolating seroprevalences from ENP to the general population and thus estimating the seroprevalence in the French population.