Experimental Trypanosoma brucei infection in rats (Rattus norvegicus): effects on different stages of gestation and the neonatal period

The purpose of the research was to examine the effects of Trypanosoma brucei infection on different stages of gestation in female albino rats (Rattus norvegicus). The animals were divided into ten groups as follows: 15 animals infected on each of the following periods of pregnancy (days) 1-3, 4-6, 7-9, 10-12, 13-15, 16-18, and 19-21; 35 uninfected animals, out of which 10 were sacrificed immediately after littering; 10 infected non-pregnant rats, and 45 uninfected females used as foster mothers. Infection with T. brucei between days 1-9 of pregnancy increased the length of gestation (P < 0.05) as well as the survival time of infected animals. The live birth index was significantly (P < 0.05) reduced in the groups infected between days 1-9 of gestation. Only the group infected on days 1-3 showed evidence of reduced post-implantation survival index. At birth and up to day 7 postpartum, litter weight was comparatively lower (P < 0.05) in the groups infected on day 1 through day 12 of gestation. However, by days 14 and 21 postpartum, litter weight in all infected groups were significantly reduced (P < 0.05) compared with the uninfected control. Litter size at birth was not significantly (P > 0.05) different in all the groups, but was lower on day 7 through day 21 postpartum. Partial fetal resorption was a prominent feature in the groups infected between days 1 and 6 of pregnancy. Placental histology revealed a placentitis characterized by diffuse perivillous fibrin deposition and lymphoplasmacytic infiltrate. It was concluded that T. brucei infection, especially during the first week of pregnancy, caused partial fetal resorption, increased the length of gestation and reduced the litter size as well as the litter weights of infected rats.