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 A ustria suffering from acute viral hepatitis, who had no known risk factors for acquiring hepatitis E. The clinical presentation and initial serologica l findings have been reported previously. In this paper we report the resul ts of sequence and phylogenetic analysis of HEV products from viral RNA iso lated from acute phase serum. The results show that HEV-Au1 is significantl y divergent from other HEV isolates. The nucleotide identity of analysed fr agments from the novel isolate ranges from 76.6 to 78.4% when compared to i solates from endemic regions and 84.6 to 87.9% when compared to isolates fr om non-endemic regions. Divergent results were obtained when serum samples taken from the convalescent phase of disease were tested with three differe nt immunoassays (EIAs). An EIA based on United States isolate-specific pept ides showed enhanced reactivity whereas EIAs based on recombinant proteins derived from prototype HEV strains from Burma and Mexico were unable to det ect antibodies to HEV (anti-HEV) in late phase serum. The findings verify t he presence of an additional HEV variant in an industrialized country and p rovide information about possible problems in detecting anti-HEV.