Investigating the Molecular Epidemiology and Transmission Dynamics of Hepatitis E Virus in Northern Nigerian Communities

Hepatitis E virus (HEV) is an understudied cause of acute viral hepatitis and a significant cause of maternal mortality in northern Nigeria, yet its molecular epidemiology, dominant genotypes, and community transmission dynamics across the North have not been comprehensively characterised. This dissertation investigates the molecular epidemiology and transmission dynamics of HEV in communities of Bauchi, Jigawa, and Niger States, representing North East, North West, and North Central zones respectively. A cross-sectional community survey enrolled 600 adults and 200 pregnant women, with serum and stool samples collected. Anti-HEV IgG and IgM seroprevalence was determined by ELISA. HEV RNA-positive samples were sequenced for ORF2 gene region to determine genotype and construct phylogenetic trees. Environmental water and pig faecal samples were also screened for HEV RNA. Anti-HEV IgG seroprevalence was 28.4 percent overall, with highest rates in Jigawa (34 percent). HEV genotype 1 dominated human isolates, consistent with human-to-human faecal-oral transmission. HEV genotype 3 was detected in pig faeces from the non-Muslim communities of Niger State, with two human genotype 3 sequences clustering with pig isolates in phylogenetic analysis, suggesting zoonotic spillover. Pregnant women had a 2.8-fold higher acute HEV prevalence than non-pregnant women. Environmental water samples from wells in flood-prone communities were HEV-positive in 12 percent of samples. The dissertation establishes the first multi-state molecular epidemiology atlas for HEV in northern Nigeria. Keywords: Hepatitis E virus, molecular epidemiology, northern Nigeria, genotype, zoonotic transmission