Prevalence, incidence and geographical distribution of Toxoplasma gondii antibodies in pregnant women in Denmark.

The purpose of this study was to determine the prevalence and incidence of toxoplasmosis in pregnant women in Denmark, and to estimate the incidence of congenital toxoplasmosis. Consecutive serum samples from 5,402 women were analysed for specific IgG and IgM Toxoplasma gondii antibodies by EIA. The prevalence of IgG antibodies was 27.4%. The seroconversion rate was estimated to be 1.16% per year (SE = 0.0017) in all age groups, consistent with an incidence of acute toxoplasmosis in pregnant women of 0.65%. Specific IgM antibodies were present in sera from 29 women. Based on an assumed maternofetal transmission rate of 50%, the incidence of congenital toxoplasmosis was estimated to be 0.33%. Based on these data it is predicted that about 410 pregnant women are infected with T. gondii every year in Denmark, and that about 200 children every year are infected in utero by T. gondii. There was no difference in the prevalence of antibodies in women from rural or urban areas, or from different parts of Denmark.