Epidemiology and Infection

Hepatitis E

A systematic review/meta-analysis of primary research investigating swine, pork or pork products as a source of zoonotic hepatitis E virus

B. J. WILHELMa1a2 c1, A. RAJIĆa1a2a3, J. GREIGa1, L. WADDELLa1a2, G. TROTTIERa4, A. HOUDEa5, J. HARRISa1, L. N. BORDENa1 and C. PRICEa1

a1 Laboratory for Foodborne Zoonoses, Public Health Agency of Canada, Guelph, Ontario, Canada

a2 Department of Population Medicine, University of Guelph, Guelph, Ontario, Canada

a3 Large Animal Clinical Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, Canada

a4 Science Branch, Canadian Food Inspection Agency, Ottawa, Ontario, Canada

a5 Food Research and Development Centre, Agriculture and Agri-Food Canada, Saint-Hyacinthe, Quebec, Canada


The objectives of our study were to identify and categorize primary research investigating swine/pork as a source of zoonotic hepatitis E virus (HEV) using the relatively new technique of scoping study, and to investigate the potential association between human exposure to swine/pork and HEV infection quantitatively using systematic review/meta-analysis methodology. From 1890 initially identified abstracts, 327 were considered for the review. Five study design types (cross-sectional, prevalence, genotyping, case-report and experimental transmission studies) were identified. A significant association between occupational exposure to swine and human HEV IgG seropositivity was reported in 10/13 cross-sectional studies. The association reported between pork consumption and HEV IgG seropositivity was inconsistent. The quantification of viral load in swine and retail pork, viral load required for infection in primates, cohort and case-control studies in humans, and formal risk assessment are recommended before specific public-health policy actions are taken.

(Accepted March 16 2011)

(Online publication April 18 2011)


c1 Author for correspondence: B. J. Wilhelm, DVM, MSc, PO Box 3339, Vermilion, AB Canada T9X 2B3. (Email: bwilhelm@uoguelph.ca)