The seroprevalence of hepatitis E virus (HEV) infection in Northeastern Asia is unknown. This study was conducted to gain insight into the epidemiology of HEV that has been obscure in Northeastern China, South Korea and Japan. A total of 1500 samples of serum were collected (300 each) from 5 groups of inhabitants over 40 years of age (Korean Chinese, indigenous Chinese, South Koreans, Koreans living in Japan, and indigenous Japanese) and screened for antibodies to HEV by the antigen-antibody-antigen sandwich Enzyme Linked Immunosorbent Assay system. The positivity for HEV antibodies was 50.7% (95%CI: 45.0-56.3) in Korean Chinese, 47.7% (95%CI: 42.1-53.3) in indigenous Chinese, 34% (95%CI: 28.9-39.5) in South Koreans, 14.3% (95%CI: 10.8-18.8) in Koreans living in Japan, and 6.0% (95%CI: 3.8-9.3) in indigenous Japanese. This result emphasizes that HEV is endemic in Northeastern Asia and tends to accumulate in developing countries. Further studies are needed to elucidate the genotype of HEV circulating in these areas and its transmission route-water-borne outbreaks, smaller outbreaks or sporadic forms attributed to zoonosis-with reference to past epidemics, food culture, and sanitary conditions.
