First report of hepatitis E virus viremia in healthy blood donors from Nepal.

The aim of this study was to detect the prevalence of hepatitis E virus (HEV) in healthy blood donors so as to decipher the maintenance of (HEV) reservoir if any. Five hundred and eighty-one blood samples along with clinical information were collected from central blood bank, Kathmandu between February and March 2014. Samples were tested for hepatitis B virus surface antigen, anti-hepatitis C virus antibodies, anti-hepatitis A virus IgM, HEV antigen, HEV viral load and anti-HEV antibodies (IgM and IgG) by ELISA. Only those samples positive with anti-HEV IgM were tested for HEV RNA by reverse transcriptase nested PCR. Age adjusted prevalence of IgM anti HEV and IgG anti HEV were 3.6 and 8.3 % respectively. No significant difference in Median ALT levels was noted between HEV RNA positive and negative subjects. Sequence analysis of HEV shows all genotype belongs to genotype 1a. Phylogenetic analysis shows the virus has homology of 95 % with strain from India and Nepal outbreak of April 2014. This study sheds light on how inter epidemic reservoirs can be maintained in healthy population with asymptomatic cases. This raises an important question regarding nature of HEV as well as its tendency to circulate in blind sight and also cause periodic outbreaks in endemic setting like Kathmandu.