In recent years, there have been successive reports of chronic hepatitis E virus (HEV) infections in the immunosuppressed, such as organ transplant patients, centered on European nations. However, neither Japan nor any of the Asian nations has thus far conducted a large-scale survey of such infections. Japan has been seeing an upturn in reported cases of hepatitis E infection, and awareness of the illness is gradually rising. Furthermore, there is concern of latent HEV infection in organ transplant patients.

A joint research team including Lecturer Yukio Oshiro of the University of Tsukuba has implemented a cross-sectional study to measure anti-HEV antibodies and HEV RNA in liver transplant patients at 17 institutes throughout Japan (Hokkaido University, Tohoku University, University of Tsukuba, University of Tokyo, Keio University, Juntendo University, Shinshu University, Kyoto University, Osaka University, Kobe University, Okayama University, Hiroshima University, University of Tokushima, Ehime University, Kyushu University, Nagasaki University, and Kumamoto University).

The results of these studies showed that 2 out of 1,651 patients measured positive for HEV RNA, the first cases of chronic hepatitis E in Japan. Additional follow-up surveys indicated that the source of the HEV infection in both cases was blood transfusion products used perioperatively.

Original Paper

Yuki Inagaki and Yukio Oshiro et.al., A Nationwide Survey of Hepatitis E Virus Infection and Chronic Hepatitis E in Liver Transplant Recipients in Japan, EBio Medicine 2, 1607?1612(2015).
DOI: 10.1016/j.ebiom.2015.09.030