Avian hepatitis E virus identified in Russian chicken flocks exhibits high genetic divergence based on the ORF2 capsid gene

A total of 79 liver samples from clinically sick and asymptomatic chickens were tested for avian hepatitis E virus (aHEV). Samples were received from 19 farms, five of which tested positive with primers targeting the ORF2 capsid gene. The phylogenetic analysis of a 242-base-pair fragment demonstrated that the Russian aHEV isolates share between 78.2 and 96.2% over the fragment sequenced, whereas the nucleotide sequence identities between the Russian isolates and the other representatives from GeneBank varied from 76.3 to 96.2%. The homology between the studied hepatitis E viruses and swine hepatitis E virus varied between 46.9 to 48.1%. The most divergent isolate aHEV16050 showed homology of 82.6% as compared with the strains in the dendrogram. The three positive hepatitis E virus samples (aHEV16279, aHEV16050 and aHEV18196) did not cluster with the European genotype 3 as expected due to the close location of Russia to Europe, nor did they with the other two genotypes, separating to a distinct branch. The aHEV16211 grouped together with European and Chinese isolates, and the aHEV18198 with Canadian ones.