High incidence of toxoplasmosis during pregnancy in Nigeria.

Sera from 606 women of child-bearing age from the Benue River Basin area of Nigeria were screened by serological tests to determine the incidence of toxoplasmosis in Nigeria; 43.7% had serologic evidence of infection, increasing from 25% in the group of 15 to 18-year-old women to 71.4% in the 39-42 year age group. Using a previously published epidemiological model, the incidence rate for each age group varied from 0.5% for 15 years old women to 5.3% in the age group 37 years, with an overall rate of 1.8%. Extending this model as it applies to the estimation of incidence of infection during pregnancy, a 5.4% expected rate of seroconversion was found.