Swine hepatitis E virus in rural southern China: genetic characterization and experimental infection in rhesus monkeys (Macaca mulatta).

Background: In rural areas of southern China, where hepatitis E is endemic, residents generally rear pigs in pigsties near their houses. The study was conducted to assess the possibility that hepatitis E virus (HEV) infections in this region are acquired primarily through contact with swine.

Methods: One hundred twenty swine fecal samples collected from pigsties located in eight rural communities of southern China were tested for HEV RNA. The swine HEV isolates were analyzed genetically and were experimentally inoculated into rhesus monkeys to determine the potential risk of cross-species infection.

Results: Twenty-nine of the 120 swine fecal samples were positive for HEV RNA. The nucleotide sequences of these swine HEV strains shared 85%-99% identities with the local human genotype 4 isolates and belonged to two subgroups of genotype 4. Importantly, swine HEV strains representing both subgroups induced hepatitis in rhesus monkeys by inoculation with the virus, evidenced by elevated serum alanine transaminase (ALT), viremia, fecal viral shedding, anti-HEV seroconversion, and liver histopathological changes.

Conclusions: Swine may be the principal reservoir for human HEV infection in rural southern China.