Rat model of congenital toxoplasmosis: rate of transmission of three Toxoplasma gondii strains to fetuses and protective effect of a chronic infection.

The incidence of congenital toxoplasmosis in Fischer rats infected between the 8th and 12th days of pregnancy with three different strains of Toxoplasma gondii (RH, 76K, and Prugniaud) were 58.2, 35.2, and 62.8%, respectively. No infected fetuses were collected from rats previously infected with RH or Prugniaud strain parasites, even if the rats were reinfected during pregnancy. Since pups from chronically infected mothers are protected from congenital toxoplasmosis, rat infection could thus constitute a relevant model for immunological studies and vaccine design.