Genome sequence analysis of an H3N2 subtype swine influenza virus isolated from Guangdong province in China

Abstract:

An H3N2 subtype swine influenza virus，A/Swine/ Guangdong/01/2005(H3N2)，was isolated from pigs with influenza-like signs in Guangdong province in 2005. Reverse transcription-polymerase chain reaction (RT-PCR) was used to amplify the gene segments for sequencing analysis. Phylogenetic analysis showed that the hemagglutinin(HA) gene of A/Swine/ Guangdong/01/2005 shared high degree of sequence identity with those of H3N2 viruses isolated from swine in Guangdong province from 2003 to 2004 and H3N2 viruses isolated from human in New York in the end of 1990s. The neuraminidase (NA) gene of this H3N2 swine virus had high degree of sequence identity with those of H3N2 viruses isolated from human in New York from 1998 to 2000. While the nonstructure (NS) gene and matrix (M) gene of this H3N2 swine virus showed high degree of sequence identity with those of classical H1N1 swine influenza viruses. These results indicated that the M and NS gene might originate from the H1N1 subtype swine influenza viruses，while the HA，NA and other genes of this H3N2 subtype swine influenza virus might originate from the H3N2 subtype human influenza viruses. Therefore，the H3N2 swine influenza virus，A/Swine/Guangdong/ 01/2005(H3N2)，is a recombinant of H3N2 human influenza virus and classical H1N1swine influenza virus.