Identification And Phylogenetic Analysis Of H5N1Avian Influenza H5N1Virus Isolated From Swine

The outbreak of the H5N1avian influenza has caused the serious economic losses in Asia.There were several reports about human infected by the H5N1avian influenza.586people have been infected and346died, the mortality rate of up to59%. It happened frequently that H5N1highly pathogenic avian influenza virus infected mammals across the species barrier. It has been found that pigs, foxes, guinea pigs, monkeys, cats, tigers and other mammals could be infected by H5N1subtype avian influenza virus. Many researchers have been concerning whether the H5N1avian influenza virus which adapts to the environment will cause a new influenza pandemic to humanbeing.The swine plays an important role in spreading and storing virus.There are both SA-a-2,6Gal(Human influenza virus receptor) and SA-a-2,3Gal(Avian influenza virus receptor) in swine respiratory epithelial cells. It means that the swine could be infected either by Human influenza virus or by Avian influenza virus,even infected at the ame time. Human influenza virus and Avian influenza virus may recombinate with each other in the swine,because the swine is a natural mixer for influenza virus.If this comes true,there will be a new influenza virus which adapts to spread in humanbeings, as a result, an influenza pandemic may happen.So to research avian influenza virus is of great scientific significance.In this study, we collected samples from lung tissue of pigs,seperated virus in SPF chick embryo after grinding,collect allantoic fluid of chick embryo and took hemagglutination tests. Only found one strain of hemagglutining,positive virus. Amplified by SPF embryos, extracted the RNA of the virus,and then amplified by the universal fluenza virus A primers,,finally we got that this isolated strain is an avian influenza virus A by1%agarose gel electrophoresis.To make a further determination of the subtype of this isolated strain, We amplified the isolated strain by specific H5N1AIV primers and obtaining obvious amplifying target bands by1%agarose gel electrophoresis. We took gene sequences of fragments of the H5N1avian influenza virus for templates, applied Primer5.0software in designing the primers of the H5N1avian influenza virus,and then asked Beijing HuaDa Co.Ltd of Biological and Technology to synthesize the primers.Then we made sequence tests of the virus genome by primers,and analyzed the sequence.The phylogenetic tree analysis revealed that the majority of virus genes were closer to the virus genes of A/Jiangsu/1/2007(H5N1),and these genes belonged to the H5N1subtype of influenza virus branch which isolated from Chinese body during2000to2010.By making amino acid analysis of the virus hemagglutinin protein (HA), we found that there was a linker peptide (PLRERRRKRG) consisted by multiple amino acids at the swine virus HA cleavage site,according to the the molecular features of the highly pathogenic avian influenza virus.All above proved that the avian influenza virus in swine could infect humanbeings. This study provides a preliminary test basis for swine H5N1avian influenza virus monitoring, researching and controling, and makes great significance to animal epidemiology and public health.