Genetic characterization of H1N1, H1N2 and H3N2 swine influenza virus in Thailand

Swine have been known to be a suitable host for influenza A virus. In Thailand, phylogenetic analysis on swine influenza virus (SIV) has as yet not been attempted. The present report presents molecular and phylogenetic analysis performed on SIV in Thailand. In this study, 12 SIV isolates from the central and eastern part of Thailand were subtyped and the molecular genetics of hemagglutinin and neuraminidase were elucidated. Three subtypes, H1N1, H1N2 and H3N2, are described. Phylogenetic analysis of the SIV hemagglutinin and neuraminidase genes shows individual clusters with swine, human or avian influenza virus at various global locations. Furthermore, amino acid substitutions were detected either at the receptor binding site or the antigenic sites of the hemagglutinin gene.