Identification of hepatitis E virus subtype 4f in blood donors in Shanghai, China

Hepatitis E virus (HEV) has been divided into eight genotypes and approximately thirty subtypes. Past studies of blood donors have revealed a substantial prevalence of HEV infection. We examined anti-HEV antibodies and HEV RNA in Chinese voluntary blood donors (VBDs). Blood specimens were collected during 2010-2011, 2014-2015, and 2018, and tested for anti-HEV IgG and IgM antibodies. HEV RNA was tested using real-time PCR and nested reverse transcription PCR (RT-PCR). Phylogenetic analysis determined the genotype using MEGA 7.0. Among 4044 VBDs, 2774 were men (68.6%). In total, 19.8% and 1.1% of the VBDs were reactive to anti-HEV IgG and IgM, respectively. The seroprevalence of anti-HEV IgG was significantly associated with age and time period (P < 0.05), whereas anti-HEV IgM was associated with anti-Treponema pallidum and time period (P < 0.05). A total of five specimens were positive for HEV RNA with normal ALT levels. Subtype 4f (n=1; in the specimens reactive to anti-HEV IgM) and 4d (n=3; 1 in the specimens reactive to anti-HEV IgM and 2 in the anti-HEV negative specimens) were found. The last specimen positive for HEV RNA was not genotyped due to failure in amplifying the partial sequence. In conclusion, our study identified HEV subtype 4f for the first time in China. Additionally, we confirmed the high prevalence of HEV in Chinese VBDs. These findings suggest a substantial risk of transfusion-transmitted HEV. Therefore, screening for HEV among Chinese VBDs might be warranted to prevent further transfusion-mediated spread of HEV.