Yur’evets, Vadimir, 600901 Russia, e-mail gin@arriah.ru, piskunov@arriah.ru, irza@arriah.ru Received August 20, 2013 Abstract Russian commercial poultry industry is tightly tied to international trade. <...> To date, avian hepatitis E virus (aHEV) has been isolated in Australia, US, Spain, Hungary, etc., being a serious threat to commercial poultry. <...> In hens, aHEV affects liver and immune system, namely spleen and thymus, disrupting homeostasis and hematological parameters. <...> In Russia, aHEV genetic identification was first reported in 2009, but the current epizootic situation in poultry remains to be unknown. <...> In this paper we report the results of genetic analysis of 415 liver samples from hens and broiler chicks aged 4-56 weeks. <...> The samples were obtained from 68 commercial farms in 36 regions of the Russian Federation and 4 commercial farms from Belarus, Kazakhstan and Ukraine during 2009 to 2012. <...> No agents causing similar clinical signs, i.e. leucosis virus, Marek’s disease virus and adenovirus, were identified. <...> In Russia, aHEV was isolated in Amurskaya, Vologodskaya, Ivanovskaya, Kaluzhskaya, Moskovskaya, Samarskaya, Saratovskaya provinces, and also in the Republic of Mari El. <...> According to RT-PCR analysis of capsid protein gene (ORF2), aHEV18198, aHEV19555, aHEV16211, aHEV18479 and aHEV18481 of 14 Russian isolates fall within European genotype 3. <...> Of 14 aHEV isolates studied, 7 samples formed a distinct genetic group. <...> Overall, the pool of HEV isolates identified in Russian chicken flocks consists of isolates belonging to European genotype 3 and isolates not yet assigned to a specific genotype. <...> The analysis of genetic variability of aHEVs isolates from different countries strongly suggests that the current classification into genotypes by geographical origin should be revised. <...> Its causative agent, the aHEV (Hepevirus: Hepeviridae) is a non-enveloped virus with a singlestranded, positive-sense RNA genome (6) that is approximately 6600 bp in size and contains three open reading frames (ORFs) (7). 5´-end ORF1 encodes the nonstructural polypeptide with several domains, including a methyltransferase domain, a papain-like cystein protease domain, a helicase domain and a RNAdependent RNA polymerase domain (8), and ORF2 <...>