Isolation And Identification Of Avian Influenza Virus H9N2Subtype HF Strain The Study On Its Biological Characteristics

Avian influenza has occurred and reports in many countries and regions around the world, itsprevention and control is the world’s focus of attention. In China, the avian flu to the poultry industry I hada lot of economic loss, avian influenza virus isolated and identified in many of our provinces andterritories have reported.Since2010spring, in the poultry farm of Anhui and other provinces immunized chicken flocks suspectedbird flu outbreak case of H9subtype, clinical symptoms mainly for respiratory symptoms, respiratorymucosal bleeding, bronchial anatomy is characterized is filled with cheese-like substance, and enlargedkidneys, heavy economic losses for farmers. In this study in order to identify cause of the disease, isolateidentify the pathogen, and its biological properties of a preliminary study, as well as the research on stemcells in the proliferative MDCK laws, and for the prevention and control of avian flu and avian flu H₉N₂the virus and the generation of cells with a certain mutual adaptation of reference.H9subtype of suspected bird flu cases Anhui of a Caoji farms of the preliminary study of the pathogenIsolation and identification of pathogenic biological characteristics of the egg inoculation and molecularbiology methods.Take the incidence of chicken spleen, lungs and trachea grinding, freezing and thawing three times,0.22μm filter, inoculated11-day-old SPF chick embryo, the blind passage on behalf of the isolated virus,determination ha titer, the use of positive serum and end dilution method of purification.Allantoic fluid sent to the National Avian Influenza Reference Laboratory subtype identification resultsshow that the H₉N₂subtype avian influenza virus, and named a/chicken/anhui/hf/2010, referred to as hflines. According to the avian influenza virus gene sequences have been published, the design eight pairs ofprimers, H₉N₂subtype of avian influenza virus gene sequences cloned and sequenced, and ha and na genesequence homology analysis and phylogenetic analysis.H9nN subtype HF strain of avian influenza virus will be inactivated allantoic fluid emulsion made frominactivated vaccine SPF chicken, weekly measurements of avian flu H₉N₂subtype antibody levels.Immunization with inactivated vaccine of the HF lines SPF chickens can quickly produce antibodies aftertwo weeks of vaccination antibody titers Jakarta to6.0log2aiv antibody titer after the first3weeks afterinoculation to reach8.0（the log2） or more, HI antibody titer basic linear growth; seven weeks aftervaccination antibody titer can be close to the peak of9.0（log2）; after vaccination four weeks to7weeksthe HI titer in the8.0（log2）⁹.0（log2） level, up to98days can still be maintained at6.0（log2） above.Description of the avian influenza virus subtype H₉N₂HF strains can stimulate the body to produce a good antibody, and the antibody can be maintained for a long time.Conducted a preliminary study found that the avian influenza virus H₉N₂subtype HF lines MDCK ofcells in1.0μm TPCK-trypsin concentration and MOI0.01can produce more on the mutual adaptation ofthe avian flu virus H₉N₂subtype HF lines MDCK of cells high ha titer, the virus in the MDCK cellproliferation.