Isolation Identification And Development Of An Oilemulsion Inactivated Vaccine Of Goose Paramyxovirus Isolate From Liaoning Province

An strainisolate of avian paramyxovirus from goose was isolated from outbreaks in Liaoning in2002, which was characterized as LN-7-02.This virus was cloned by plaque and characterized by hamagglutination profile.This virus was able to agglutinate chicken red blood cells which can be inhibited by Newcastle disease virus and goose paramyxovirus standred antiserum.This virus was lethal to SPF chicken embryos, duck embryos and goose embryos and resulted in 100% mortality. Morphological examination showed that this virus was polymorphous enveloped with anapproximate diameter of 200nm.The in vivo pathogencity tests showed that the isolate LN-7-02 belonged to immediate type NDV and was much virulent when it was judged by mean death time of chick embryos (MDT), intracerebral pathogenicity index in day old chicks(ICPI). (The EID50 was 108. 6/ml and MDT was 56 h in embryonated chicken eggs.ICPI was 1.94 in new hatched chicks) .The recurrent infection showed that this virus Could infect goose, chicken and pigeon with 100% mortality , but no pathoegnicity to the duck.In the research, By reverse transcription polymerase chain reaction, the product of part F gene from LN-7-02 isolate was obtained and cloned to PMD18-T, the sequence of the region from 1 to 539 of F genes was determined. The deduced amino acidsequence of the cleavage site region from LN-7-02 Was 112R-R -Q-K-R-Fl 17, matching to virulent (velogenic) Newcastle disease virus. The results demonstrated that this virus was high Virulent strain and correlated with the virulence of the isolate in biological assays. The comparison of F gene of LN-7-02 solate and the domestic standard vologenic strain NDVF48E9, had revealed 86.5% homology innucleotide sequences, The LN-7-02 isolate was closer to genotype VIINDV strain prevalent, which had much more similarity with Ch2000 and four NDV strains from Liaoning such as LN-4-02, LN-5-02, LN-6-02 and LN-8-02, So it was suggested that LN-7-02 was a variant of APMV-1.Based on sequence analysis of the first 374bp nucleotides of the coding region of F-gene, a phylogenetic tree of NDV strains was constructed. All analysis NDV strains circulated from 1940's to now were divided into nine genotypes. The LN-7-02 isolate in this study and four NDV strains from Liaoning all belonged to group D, which is a novel genotype of NDV in China.A new viral disease of goose was reported by Wang yong kun etc. The earlier study results showed that this virus classified as paramyxoviridae-Goose-Paramyxovirus. After then, we have made ill emulsion inactivated vaccine from LN-7-02 of goose paramyxovirus strains of isolated virus. The safety test in field goose, kinetics of antibodies response generated, protective rate of challenged and duration of immunity, the result indicated that the antibodies against LN-7-02 were generated 7 days post inoculation and the Highest antibodies were generated post 30 days. The HI titer is 8 Iog2, At 15 day post immunization, the protectivity is 100%, in the end, this vaccine is testified to be safe, effective and could give good protection against infection.