بهبود کیفیت واکسن غیر فعال آنفلونزا ی طیور ‭(H9N2)‬

Detection of respiratory viruses among affected commecial chickens flocks experiencing sever respiratory disease with fibrinonecrotic casts at the bronchi and bifurcation of the trachea and relative high mortality showed that coinfection of avian influenza subtype H9N2 and infectious bronchitis virus serotype 4/91 in combination with the current field bacteria are the most important causative agents for fibrinonecrotic casts formation and mortality under field condition in Iran. Inactivation of V4 strain of Newcastle disease virus (NDV) and H9N2 virus by binary ethylenimine (BEI) and formaline for production of monovalent and bivalent oiladjuvant vaccines were carried out. HI titers against ND vaccines showed that inactivation with BEI had induced highest titers of antibodies in chickens, whereas in avian influenza vaccines group inactivation with BEI had induced lowest HI titers. These findings indicated that BEI successfully inactivated both V4 and H9N2 viruses; however, formalin-inactivated avian influenza vaccine produced better immunogenicity than the vaccine prepared with BEI, whereas BEI-inactivated ND vaccine produced better immunogenicity than the vaccine prepared with formalin. Moreover, comparison of oil-adjuvant and Aluminum hydroxide gel-adjuvant of the inactivated bivalent vaccine showed more strength and stability for oil-adjuvant vaccine than the vaccine containing Aluminum hydroxide gel, however, antibody titers obtained from both the vaccines were above the protective level for both viruses. Because of non-highly pathogen nature of H9N2 virus, it was not possible to practice efficacy test for the commercial H9N2 vaccines. Therefore, virulance of the H9N2 was increased by coinfection of the vius with E. coli in which could produce constant mortality among young chickens. The results indicated that the optimized procedure can be used as a new efficacy test for evaluation of the protective level in H9N2 influenza vaccines. Key words: H9N2, 4/91, binary ethylenimine, vaccine, Aluminum hydroxide gel

کلیدواژه ها:

آنفلوآنزاویروس ، طیور ، واکسن(ها) ، بیماری نیوکاسل