我国野鸟新城疫病毒流行调查及遗传进化分析

Epidemic investigation and genetic Evolution Analysis of Wild Bird Newcastle Disease virus in China

目的掌握我国野鸟中新城疫病毒(NDV)的流行及遗传进化特征。方法结合候鸟的分布、迁徙规律以及栖息环境等信息,在途经中国的东亚-澳大利亚和西太平洋候鸟迁徙路线及其他重要野鸟栖息、停歇地作为监测哨点,采集环境样品、组织及咽肛拭子等样品进行NDV鉴定,阳性样品按照地域、物种和采集时间划分挑取代表株并进行F基因序列测定,构建NJ进化树并分析F蛋白裂解位点。结果2013-2021年共采集环境样品、拭子及组织样品113017份,分离获得67株候鸟NDV,均来自常规监测中采集的拭子和环境样品,死亡野鸟中未检出NDV。历年野鸟中NDV的分离率分别为:2013年0.21%,2014年0.23%,2015年0.04%,2016年0.05%,2017年0.03%,2018年0.03%,2020年0.06%,2021年0.01%。F基因遗传进化分析表明,26株代表株中有20株NDV为ClassⅠ(14株genotypeⅠ.1.1.2,6株genotypeⅠ.1.2),宿主分布为苍鹭、赤麻鸭、斑嘴鸭、红腹滨鹬、海鸬鹚及鸥类;6株NDV为ClassⅡ(1株为genotypeⅠ.1.1,1株为genotypeⅠ.1.2.1,4株为genotypeⅠ.2),宿主分布为豆雁、翘嘴鹬、绿头鸭、红头潜鸭。经F蛋白裂解位点分析,26株新城疫病毒代表株均符合弱毒株分子特征。结论新城疫病毒野鸟宿主种类呈多样性,且同时存在ClassⅠ和ClassⅡ两类新城疫弱毒株。可为我国野鸟中新城疫病毒的流行、进化和宿主多样性提供数据资料。

Objective To master the epidemic and genetic evolution characteristics of Newcastle disease virus(NDV)in wild birds in China.Methods Based on the information of the distribution,migration law and habitat of migratory birds,environmental samples,tissues and throat and anal swabs were collected from the migratory routes of East Asia to Australia Flyway and the Western Pacific Flyway through China and other important habitats and resting places of wild birds as monitoring sentinel points for NDV identification.Representative strains of positive samples were selected according to region,species and collection time and F gene sequence was determined.N-J tree was constructed and the F protein cleavage site was analyzed.Result A total of 113017 environmental samples,swabs and tissue samples were collected from 2013 to 2021,and 67 strains of migratory birds NDV were isolated,all of which came from swab and environmental samples.No NDV positive sample was found in dead wild birds.The isolation rates were 2013(0.21%),2014(0.23%),2015(0.04%),2016(0.05%),2017(0.03%),2018(0.03%),2020(0.06%)and 2021(0.01%),respectively.Genetic evolution analysis of F gene showed that 20 NDV of the 26 representative strains were class I(14 strains belong to genotype I.1.1.2 and 6 strains belong to genotype I.1.2)and the host distribution was Grey Heron,Ruddy Shelduck,Spot-billed Duck,Red Knot,Resplendent cormorant and Gulls;6 strains of NDV were Class I(1 strain belong to genotype I。1.1,1 strain belong to genotype I.1.2.1 and 4 strains belong to genotype I.2)and the host distribution was Bean goose,Xenus cinereus,Common Mallard and Common Pochard.All 26 representative strains of Newcastle disease virus matched the molecular characteristics of the attenuated strain by F protein cleavage site analysis.Conclusion NDV presents host diversity in wild birds,and two weak Newcastle disease strains,Class I and Class I existed simultaneously.The results could provide data for the epidemic,evolution and host diversity of Newcastle disease virus in Chinese wild birds.