| Avian influenza(AI) is caused by influenza A virus that belongs to the family Orthomyxoviridae,genus Influenza A.It rapidly infects poultry and causes multiorgan systemic disease when it breaks out and leads to high rate of morbidity and mortality and led much economical losses in various countries.Furthermore,occurrences of direct bird-to-human transmission of AIV even dying have increasingly been reported in recent years.AI is a persistent potential health threat to both domestic and human species seriously as well as wild species.It is generally accepted that wild aquatic birds provide a natural reservoir of avian influenza viruse and play an important role in spreading.An avian influenza A virus was isolated from a Garganey in SanJiang natural reserve of HeiLongiiang province in October,2006.The subsequent indentification comfirmed it as a H5N2 virus by National Influenza Reference Laboratory,and was named as A/Garganey/SanJiang/106/2006 (H5N2).The primers were designed specific to A/Garganey/SanJiang/106/2006 (H5N2),then amplified the genome(within ORFs) of HA,NA,PB1,PB2,PA,NP,M and NS.The eight full-length cDNAs of the virus genes were amplified by RT-PCR,and inserted into PMD-18T vector,and the recombinant plasmid was transformed in competent DH5-αE.Coli,then sequenced when the PCR result was positive for amplifying the inserted gene in recombinant plasmid.The phylogenetic tree based on sequences showed this strain originates to the H5N2 viruses isolated from the Southern China.The homology of HA and NA are 92.9%～98.3%and 93.6%～98.7%.The homology of the other 6 genes are also above 90%.According to these results,A/Garganey/SanJiang/106/2006(H5N2) would be transmit acrossed the species barrier to from domestic poultys to the Garganey.The cleavage site of HA gene is 5'-PQRETR'GLFG-3',that is similar to LPAIV HSN2 viruses.Based on analysing some special amino acids' changed to prove that A/Garganey/SanJiang/106/2006 (H5N2) is a LPAIV.
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