Hepatitis E outbreak in a mechanical factory in Qingdao City, China

Objective: In July 2018, recurrent hepatitis E cases were reported from a factory in Qingdao City, China. The aim of this study was to identify additional cases, and help prevent future incidents by identifying possible risk factors for infection. Methods: Participants were asked to provide blood samples for hepatitis E virus (HEV) IgM and IgG antibodies screening, as well as liver function test. A questionnaire that assessed demographics, potential risk factors, and clinical symptoms was completed by participants. HEV RNA genotyping was performed using a nested Reverse Transcriptional Polymerase Chain Reaction (RT-PCR) method. Adjusted Poisson regression model for participant characteristics and risk factors was constructed for multivariate analysis. Results: Overall, 41(14.5%, 41/283) participants had recent acute infection (21 of these were symptomatic). The result of multivariate analysis demonstrated a significant association of acute HEV infection with consumption of pig liver within the past two months (Relative Risk 2.61, 95% confidence interval (CI) 1.10–6.17, p = 0.0294). Sequencing of HEV RNA from seventeen acute cases indicated three HEV isolates of genotype 4 induced this outbreak. Conclusions: This was probably a common-source foodborne hepatitis E outbreak, related to the consumption of undercooked pig liver. Keywords: Hepatitis E, Foodborne diseases, Zoonoses