Molecular characterization and phylogenetic analysis of the complete genome of a hepatitis E virus from European swine.

Hepatitis E virus (HEV) has been detected in humans and in a broad range of animals, including pigs. For the first time the full-length genomic sequence of a HEV of European porcine origin, termed swX07-E1, was determined. Comparative analysis of 76 complete or nearly complete nucleotide sequences showed that swX07-E1 shares the highest nucleotide identity with Japanese swine HEV swJ8-5 and swJ12-4. The whole-genome phylogenetic analysis showed that swX07-E1 from Europe belongs to genotype-3 HEV, clusters with variants from Japan, Mongolia and Kyrgyzstan in subgroup 3c, but it is divergent from the prototype US HEV. Our analysis indicates that swX07-E1 represents a new subgroup of genotype-3 and that analysis of full-length sequences is necessary to discover new subgroups of HEV. According to our knowledge, swX07-E1 is the first full-length genome sequence of HEV from European swine. Knowledge about the full length HEV sequence from European swine is very important for understanding the HEV evolutionary events and the molecular mechanism of infection in human and in animals.