秦岭野鸟源新城疫病毒致病性与F、HN基因分子特征分析

Characterization of F,HN Genes of the Newcastle Disease Virus Isolates from Wild Birds in Qinling Mountains

为研究新城疫病毒(NDV)在秦岭地区野生鸟群中的流行情况,在秦岭地区采集健康野鸟咽喉、泄殖腔拭子各252份,进行NDV的分离、鉴定,并对NDV分离株进行生物学特性研究和遗传进化分析。结果共分离获得5株野鸟源NDV,其致病指数MDT、ICPI和IVPI分别为60.0～76.8h、0.900～1.261、0.41～0.81;对F基因(47～420bp)进行遗传进化分析,5株分离株均属于基因VIb型,F蛋白裂解位点为112 RRQKRF117;HN基因氨基酸相似性为99.5%～99.8%,与鸽源基因VI型NDV相似性为91.4%～98.0%,与LaSota、F48E9相似性分别为87.1%～87.4%、89.0%～89.3%。上述结果表明,基因VIb型NDV在秦岭地区健康野生鸟类中流行,可能源于鸽源NDV,并具有强毒力的分子特征,但对鸡的表现为中等致病力,说明野鸟NDV具有独特的分子特征和致病性。

In order to explore the epidemiological status of Newcastle disease virus （NDV） among wild birds in Qinling Mountains. Two hundred and fifty two throat and cloacal swabs obtained from healthy wild birds used to isolate NDV which characterized by both biological and genetic evolution analysis. Five NDVs were isolated and identified, their MDT, ICPI and IVPI were 60.0-76.8 h, 0. 900-1. 261 and 0. 41-0. 81, respectively. Deduced amino acid sequences of the cleavage sites of fusion （F） protein revealed that all strains had the same motifs （112RRQKRFnr）. Phylogenetic analysis of partial F gene （47-420 bp） showed that 5 NDVs belong to VIb genetype. By comparison of the deduced amino acid sequences of hemagglutinin-neuraminidase （HN） glyco- protein, the homology among the 5 isolates was 99.5%-99.8%, shared 91.4%-98.0%,87. l%- 87.4% and 89.0%-89.3%identities with VI pigeon NDV, LaSota and F48Eg,respectively. The results suggested that there are genetype VIb NDVs in Qinling area, with velogenic molecular characteristics and moderate pathogenicity index, maybe have the same origins with pigeon NDV.