Hepatitis E Virus Exposure at the Human–Pig Interface: Seroprevalence Among Pregnant Women and Slaughter Pigs in Tanzania

Abstract

Background: Hepatitis E virus (HEV) is a major cause of acute viral hepatitis worldwide and can lead to severe complications, particularly among pregnant women. In sub-Saharan Africa, outbreaks occur periodically, yet routine surveillance remain limited. Domestic pigs are known reservoirs of zoonotic HEV genotypes, raising concern about transmission at the human–animal interface. However, evidence on HEV exposure in both humans and pigs in Tanzania is scarce. This study assessed the seroprevalence of HEV among pregnant women and slaughter pigs in resource-limited communities in Tanzania.
Methods: Cross-sectional study was conducted between September 2023 and July 2024 in Dodoma and Morogoro regions. Pregnant women attending antenatal care clinics and pigs presented for slaughter at municipal abattoirs were systematically sampled. Serum samples were tested for anti-HEV IgG antibodies using a commercial enzyme-linked immunosorbent assay (ELISA). Sociodemographic data from women and pig husbandry practices were collected using structured questionnaires. Descriptive statistics were used to estimate seroprevalence with 95% confidence intervals (CIs). Associations between HEV seropositivity and risk factors were assessed using Chi-square or Fisher’s exact tests, followed by logistic regression analysis.
Results: A total of 372 pregnant women and 280 pigs were included in the study. HEV seroprevalence was 15.1% (95% CI: 11.8 – 19.0) among women and 32.9% (95% CI: 27.6–38.6) among pigs. Higher seropositivity among women was observed in the 25 to 34-year age group. In pigs, housing systems, water sources, and farm biosecurity practices were associated with HEV infection.
Conclusion: These findings demonstrate concurrent HEV exposure in humans and pigs in central Tanzania. The higher prevalence in pigs supports their role as potential reservoirs, while detection in pregnant women suggests ongoing community transmission. Strengthening surveillance and adopting a One Health approach integrating maternal health services, veterinary monitoring, and improved farm biosecurity are essential to reduce zoonotic transmission risks.