Investigation of early life exposure to infectious pathogens and their association with microcephaly in Rwandan children

Abstract

Background: Microcephaly is a clinical condition characterized by a head circumference more than two standard deviations below the mean for an individual’s age and sex. This condition can result from various risk factors, including exposure to infectious pathogens. However, there is a paucity of data describing the association between early-life exposure to infectious pathogens and microcephaly among Rwandan children. Aim: This study aimed to investigate early-life exposure to infectious pathogens in Rwandan children and evaluate their potential association with microcephaly. Method: This cross-sectional case-control study included 120 participants (30 children with microcephaly and their mothers as case and 30 age-matched healthy children and their mothers as controls). The study was conducted from November 2023 to July 2025 at the University Teaching Hospital of Kigali. IgM and IgG antibodies against Toxoplasma gondii, Rubella virus, Cytomegalovirus (CMV), Herpes simplex virus, Zika virus, and Human Immunodeficiency Virus (HIV) were tested using rapid diagnostic tests. Data were analyzed using SPSS version 28, with statistical significance set at p < 0.05. Results: Children with microcephaly had significantly smaller head circumferences (P = 0.001), lower birth weights (P = 0.026), and shorter heights (P = 0.003) than the controls. Maternal infection during pregnancy was significantly linked to microcephaly (OR=4.33, 95%CI:1.20–15.61; P=0.02). Serological analysis showed a higher positivity rate of IgG for Rubella among children with microcephaly (22.5%) than controls (13.3%) (OR=7.875; 95% CI: 1.958–31.675; P=0.004), and CMV IgG 7.5% in case vs 0% in controls, (OR=27, 95% CI 1.5-488; P=0.02). Similarly, 40% of case mothers tested positive for Rubella IgG versus 8.3% of controls (Odds Ratio=4.8; 95% CI: 2.1–10.9; P<0.0001), and CMV IgG positivity was 23.3% in case mothers compared to 0% in controls (OR=53.6; 95% CI: 3-957; P=0.007). Conclusion: This study highlights early life exposure to infectious pathogens, specifically Rubella and CMV, in children with microcephaly in Rwanda, suggesting that infectious disease prevention before conception or during pregnancy is very important in preventing congenital defects.