Experimental toxoplasmosis in BALB/c mice. Prevention of vertical disease transmission by treatment and reproductive failure in chronic infection

In a study of congenital transmission during acute infection of Toxoplasma gondii, 23 pregnant BALB/c mice were inoculated orally with two cysts each of the P strain. Eight mice were inoculated 6-11 days after becoming pregna nt (Group 1). Eight mice inoculated on the 10th-15th day of pregnancy (Grou p 2) were treated with 100 mg/kg/day of minocycline 48 h after inoculation. Seven mice inoculated on the 10th-15th day of pregnancy were not treated a nd served as a control (Group 3). Congenital transmission was evaluated thr ough direct examination of the brains of the pups or by bioassay and serolo gic tests. Congenital transmission was observed in 20 (60.6%) of the 33 pup s of Group 1, in one (3.6%) of the 28 pups of Group 2, and in 13 (54.2%) of the 24 pups of Group 3. Forty-nine Balb/c mice were examined in the study of congenital transmission of T. gondii during chronic infection. The femal es showed reproductive problems during this phase infection. It was observe d accentuated hypertrophy of the endometrium and myometrium. Only two of th e females gave birth. Our results demonstrate that Balb/c mice with acute t oxoplasmosis call be used as a model for studies of congenital T. gondii in fection. Our observation indicate the potential of this model for testing n ew chemotherapeutic agents against congenital toxoplasmosis.