Study On Genotype Of NDV Strain Isolated And Compound Inactivated Vaccine Made By Isolates

Four strains of Virus were isolated from specimens collected in outbreaks in Hebei and Heilongjiang provinces between 1999 and 2002, and named than as HeB-4-99, HeB-5-99, HeB-6-02 and HLJ-10-02, respectively. All the isolates can induce chicken embryo death in 48-72 hours, allantoic fluids of dead embryo have Hemagglutinin(HA) activity, and HA activity can be inhibited by ND standard anti-serum. Chickens inoculated with the isolates in regress test showed symptoms and lesions of ND, and virus can be reisolated, so the isolates were confirmed as NDV. Results of Intracerebral Pathogenicity Index (ICPI) and Median Embryonal Lethal Dose (ELD50) showed that all isolates belong to velogenic strain.By Reverse Transcription Polymerase Chain Reaction(RT-PCR), partial segment of F gene from NDV isolates were cloned and sequenced, Amino acids deduced showed amino acids within F cleavage site were 112RRQKRF117, have the same amino acids pattern as velogenic strain. It can answer for the value of ICPI and MDT. DNA sequence analysis showed that they shared homology between 95.9%-100%, shared 81.0%-81.8% with NDV La Sota, and shared 85.8%-89.3% with NDV F48E9, respectively. Based on the first 374bp nucleotides initiated from the first ATG of F gene, phylogenetic tree of NDV strains was drawn by the total 73 NDV strain including isolated in the study and recent isolates in China and some strain aboard. Four strains in this study belonged to group VII, which is a novel genotype of NDV in China.Compound inactivated oil-emulsion vaccine was made by isolates and ND La Sota. The efficacy of ND La Sota inactivated vaccine, compound inactivated vaccine and compound inactivated vaccine plus live ND La Sota vaccine were compared. All the groups were protected after challenge. The titers of NDV specific HI antibody in compound inactivated vaccine group is higher than that of La Sota inactivated vaccine, it indicated that the compound inactivated vaccine can offer high level efficiency.Four strain of typical NDV was isolated in China, the biological character were analyzed ,the segment of F gene were amplified, the phylogentic tree was drawn and the genotype were studied, the compound inactivated vaccine was made and the efficiency was compared. Thestudy laid foundation for the prevention of ND.Candidate: Han Zhengbo; Speciality: Basal Veterinary Science Supervisor: Prof. ZhengShimin PanXingguang...