Biological Characteristics Of H5 Avian Influenza Virus And The Construction Of Gene Recombinant Vaccine

H5N1 avian influenza virus caused 6 deaths of 18 infected humans in Hong Kong in 1997 and many deaths of infected humans in the worldwide H5N1 avian influenza outbreaks recent years, All this suggested this subtype viruses pose severe threat for pubic health.The present study performed biological characterizations of 1 H5N1 virus strain that isolated from China mainland in 2003. Firstly, this virus named as A/Duck/Guangxi/27/03 (H5N1) was sequenced and compared with fifteen H5N1 AIV strains isolated from different regions in East Asia during the period of 1996 to 2006. DNA sequence analysis of this virus genes showed that the HA,NA,NP and M genes of the virus shared very high homology with A/Goose/Guangdong/1/96 and there were a few of continuous base amino acids in cleavage site of HA gene.But other genes of this virus strain were comparatively far related with A/Goose/Guangdong/1/96.Secondly, this virus strain was highly pathogenic to chicken according to the test of chicken's pathogenecity. Results showed that fifty percent of Egg Infective Doses (EID50),Intravenous Pathogenecity index (IVPI) to chicken of this virus,Mean Death Time to chicken of intravenous inoculated virus were 10-8.38/ml, 3.00, 1day respectively. Furthermore, this virus strain was evaluated in a model of BALB/c mice in order to test this virus's pathogenecity to the mammal. 50% Lethal Doses to BALB/c mice (MLD50) of this virus strain was 100.63EID50. The highest virus titers in the mice's tissue and organs were lung and spleen, but this virus titer in the lung and spleen was lower on the 6th day than the 4th day. The virus was also replicated in kidney and spleen. Results indicated the H5N1 avian influenza virus which was highly pathogenic to chicken had the ability to infecting and killing mice.H5N1 highly pathogenic avian influenza is responsible for one of the most devastating diseases in domestic poultries. Vaccination has been proved to be a useful tool for the avian influenza control. We generated a low-pathogenicity/high growth H5N2 virus by using plasmid-based reverse genetics.The HA and NA gene of this virus strain were derived from A/Tuekey/England/N28/73 (H5N2) and the other 6 internal genes were derived from a high growth virus A/PuertoRico/8/34 (H1N1). The constructed recombinant virus is a good base for experiment and theory in order to prevent and control of H5N1 AIV.