Both C57BL/KsJ (H2d haplotype) and CB10-H2 (H2b haplotype) mice are highly susceptible to congenital toxoplasmosis.

Congenital toxoplasmosis may cause abortion, neonatal death, or foetal abnormalities. Despite little information from human studies, a genetic influence over congenital disease was demonstrated and, host genome have been implicated to resistance/susceptibility to Toxoplasma gondii infection in both human and mice. It was previously shown that BALB/c mice (H2d) were more resistant to congenital toxoplasmosis than C57BL/6 mice (H2b). However, it is unclear whether these differences are attributable to the MHC haplotype or to other components of the mouse's genetic background. Therefore, in this work, we intend to address this question by investigating the pregnancy outcome in H2d -congenic C57BL/6 mice (C57BL/KsJ-H2d) and H2b-congenic BALB/c mice (CB10-H2-H2b). For this, animals were infected by intragastric route on the first day of pregnancy and examined on days 8 (8dP/8dI) or 18 (18dP/18dI) of gestation and infection. The pregnancy outcome, parasite burden, systemic cytokine profile and antibody response to infection were evaluated. Infected mice showed adverse pregnancy outcomes, in parallel low parasite detection in the uterus/placenta, being that the C57BL/KsJ showed the worst results in relation to CB10-H2 mice. Both mouse lineages showed an increase in IFN-γ and TNF levels systemically on 8dP/8dI and on 18dP/18dI, and C57BL/KsJ showed an increase in IL-6 levels in both gestation/infection periods. Additionally, C57BL/KsJ showed 7- and 7-fold increase in IL-6, 4- and 2.5-fold increase in IFN-γ and, 6- and 4-fold increase in TNF production on 8dP/8dI and 18dP/18dI, respectively in association with 1.5-fold decrease in TGF-ß levels on 8dP/8dI compared to CB10-H2 mice. In conclusion, the high IFN-γ and TNF serum levels observed in C57BL/KsJ (H2d) and CB10-H2 (H2b) mice were involved in the poor pregnancy outcomes in congenital toxoplasmosis. In addition, the higher IFN-γ, IL-6 and TNF levels detected in C57BL/KsJ in relation to CB10-H2 mice on 8dP/8dI seem to be related to the genetic background of C57BL/6J mice that may have contributed to the worse pregnancy outcome in this mouse lineage.

Infectious diseases during pregnancy in Brazil: seroprevalence and risk factors.

INTRODUCTION: Vertically transmitted infections are caused by a diversity of pathogenic microorganisms. Pregnant women are routinely screened to evaluate the risks and reduce the burden of disorders in their unborn children. We assessed the prevalence and possible risk factors for Cytomegalovirus (CMV), Rubella, Human T lymphotropic virus (HTLV), and Toxoplasma gondii in pregnant women from the South region of Bahia State, Brazil. METHODOLOGY: Serum samples were obtained from 726 pregnant women aged between 13 and 44 years, with a median age of 24 years. ELISA assays were used to detect CMV, Rubella, HTLV and T. gondii IgG and IgM antibodies. RESULTS: The prevalence rates of IgG antibodies found were 95.2% for CMV, 97.0% for Rubella, and 72.3% for T. gondii. Furthermore, the prevalence of HTLV-1/2 was 1.2%. IgM antibodies were reactive only for CMV (0.8%) and T. gondii (3.7%). Variables independently associated with the detection of anti-T. gondii IgG antibodies were white self-reported race/ethnicity (Odds Ratio [OR] 2.26, 95% CI 1.26-4.06, P = 0.006), wage income (OR 0.55, 95% CI 0.35-0.88, P = 0.013), and history of previous pregnancy (OR 1.60, 95% CI 1.02-2.50, P = 0.038). CONCLUSIONS: This study highlights the importance of monitoring for infectious diseases during pregnancy and initiation of early interventions to reduce the burden of fetal losses and other important infant sequelae attributable to congenital infections.