Epidemiological characteristics of hepatitis E virus infection in West Africa: A systematic review and meta-analysis of human, animal, and environmental data (1997–2025) with risk-group stratification and genotype mapping

Abstract

Background and Aim: Hepatitis E virus (HEV) is an important cause of acute viral hepatitis worldwide and remains a neglected public health concern in sub-Saharan Africa. Although several African studies have reported HEV circulation, no comprehensive synthesis has integrated human, animal, and environmental evidence from West Africa. This study aimed to determine the prevalence, geographic distribution, risk-group characteristics, and genotype diversity of HEV in West Africa using a One Health approach. Materials and Methods: A systematic review and meta-analysis was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and registered in PROSPERO (CRD420251178069). PubMed, ScienceDirect, Google Scholar, and reference lists were searched for studies published between 1997 and August 2025. Studies involving humans, animals, and environmental samples from West African countries were included. Data extraction and quality assessment were performed independently by two reviewers. A random-effects meta-analysis using Comprehensive Meta-Analysis software version 3.0 was conducted to estimate the pooled prevalence and investigate heterogeneity. Human populations were stratified into low- and high-risk groups according to exposure characteristics. Results: Ninety-six eligible studies conducted in 12 countries and involving 36,014 individuals were included. A total of 9,465 HEV-positive cases were identified. The pooled overall seroprevalence was 9.7% (95% confidence interval [CI]: 8.2%–11.5%), with substantial heterogeneity (I² = 97.53%). The pooled prevalence of anti-HEV immunoglobulin (Ig)G was 15.7%, ranging from 2.7% in Guinea to 29.3% in Burkina Faso. High-risk populations exhibited higher prevalences of IgG (25.9%), IgM (4.6%), and total antibodies (16.9%) than low-risk groups. Animal reservoirs, particularly pigs, showed high infection frequencies, whereas environmental contamination reached 24% in vegetables. Human genotypes 1e, 2b, 3e, 3f, and 4b, and animal- and environment-associated genotypes 3a and 3c were identified across the region. Conclusion: HEV infection is widely distributed in West Africa, with marked differences among countries and population groups. The coexistence of human, animal, and environmental reservoirs highlights the importance of integrated One Health surveillance and targeted prevention strategies to reduce the regional burden of HEV infection. Keywords: environmental contamination, genotype distribution, hepatitis E virus, meta-analysis, One Health, prevalence, systematic review, West Africa.