Isolation,Identification Of Newcastle Disease Virus And Research And Application Of Inactivated Vaccine Of HB Strain

Pigeon Newcastle disease is a high-contact infectious disease commonly caused by Pigeon Paramyxovirus I?PPMV-I?.The“gather”mode and training of the pigeons have led to the prevalence of the disease in the pigeon population.The current vaccines which prevent pigeon ND are mainly chicken ND vaccine.Due to differences between the PPMV-I and APMV-I in genotypes,the protection rate of chicken ND vaccine in pigeon is lower than that of in chicken.As the reasons mentioned above,this study mainly isolate and identify typical pathogenic ND virus from clinically sick pigeons,carries out inactivated vaccine study of the isolated strain with the purpose of providing reference for the prevention and control of clinical pigeons Newcastle disease.The isolation,identification and pathogenicity test of Newcastle disease virus from pigeon sheds in Hebei,Inner Mongolia and Tianjin were carried out in in this study.In this way,the typical pathogenic isolates were selected for virulence determination and related vaccine research and application.Results:In this study,five strains were isolated from suspected pigeon ND cases and confirmed to be ND virus.Among them,the isolated strains of Hebei Province showed typical clinical symptoms and necropsy changes of Newcastle disease in the pathogenicity test of artificial infection,and the mortality rate was 100%.The MDT,ICPI and IVPI of Hebei isolate strain were 52.8 h,1.78,and 2.59,respectively.So the isolate was named HB strain.The gene sequence and deduced amino acid sequence showed that the cleavage site of the F protein of this strain was ¹¹²R-R-Q-K-R-F¹¹⁷,which was consistent with the characteristics of the Newcastle disease virulent strain,and its genotype was type VI.The best inactivation condition for the virus used in the vaccine was:0.1%formaldehyde,inactivation temperature of 37?,inactivation time of 16h.The optimal adjuvant is French imported water adjuvant.The safety,optimal immune dose,antibody production time,immune duration and shelf life test shows that inoculated subcutaneously 0.3ml,the antibody is produced on the 7th day post-inoculation?pi?,and the average of HI titer reaches to 2⁶ after 2 weeks pi.The peak was reached 2⁹on 4 weeks pi;The protection rate for vicious challenge at 90 days after immunization was 100%.Clinical application shows that the vaccine has good control effect on pigeon Newcastle disease.