Identification of a novel variant of hepatitis E virus in Austria: sequence, phylogenetic and serological analysis.

We isolated a novel hepatitis E virus (HEV-Au1) variant from a patient in Austria suffering from acute viral hepatitis, who had no known risk factors for acquiring hepatitis E. The clinical presentation and initial serological findings have been reported previously. In this paper we report the results of sequence and phylogenetic analysis of HEV products from viral RNA isolated from acute phase serum. The results show that HEV-Au1 is significantly divergent from other HEV isolates. The nucleotide identity of analysed fragments from the novel isolate ranges from 76.6 to 78.4% when compared to isolates from endemic regions and 84.6 to 87.9% when compared to isolates from non-endemic regions. Divergent results were obtained when serum samples taken from the convalescent phase of disease were tested with three different immunoassays (EIAs). An EIA based on United States isolate-specific peptides showed enhanced reactivity whereas EIAs based on recombinant proteins derived from prototype HEV strains from Burma and Mexico were unable to detect antibodies to HEV (anti-HEV) in late phase serum. The findings verify the presence of an additional HEV variant in an industrialized country and provide information about possible problems in detecting anti-HEV.