Prevalence of hepatitis E virus infection in Japanese children

Background: Recently, sporadic cases of acute hepatitis and fulminant hepatitis caused by hepatitis E virus (HEV) have been reported in Japan. However, few reports have addressed the issue of HEV infection during childhood. Methods: This study included 5 patients with fulminant hepatitis, 30 patients with acute hepatitis, and 309 patients without history of hepatic dysfunction or hepatitis in childhood as control. RNA was extracted from each serum sample, and HEV specific reverse-transcriptase polymerase chain reaction was performed. Anti-HEV immunoglobulin (Ig)M and IgG were measured by enzyme-linked immunoadsorbent assay. Results: HEV RNA, anti-HEV IgM, and anti-HEV IgG were not detected in the sera of any of the five patients with fulminant hepatitis. In the 30 patients with acute hepatitis, only one (3.3%) was positive for anti-HEV IgG, and all were negative for anti-HEV IgM and HEV RNA. Of the 309 control patients, 8 (2.6%) were positive for anti-HEV IgG, and 2 (0.6%) were positive for anti-HEV IgM, respectively. Conclusion: The result of patients with fulminant hepatitis suggests that HEV is an unlikely cause of fulminant hepatitis in children. However, the detection rate of anti-HEV IgG shows that a history of HEV infection is not so rare among children in Japan.