辽宁省养殖环节非洲猪瘟疫情流行病学特征

Epidemiological Characteristics of the Outbreak of African Swine Fever in Pig Production in Liaoning Province

从2018年8月发现我国首起非洲猪瘟(ASF)疫情至2020年7月,辽宁省共报告养殖环节ASF疫情18起,涉及24个养殖场户。为掌握辽宁省养殖环节的ASF疫情流行病学特征,对这些疫情的现场流行病学调查结果开展了描述性分析,呈现其时间、空间、群间分布特征,统计发病率、病死率等流行病学指标,分析病毒进入疫情场户的可能途径。辽宁省养殖环节ASF疫情可追溯至2018年6月上旬或中旬,在2018年9—10月呈现时空聚集性特征。母猪、育肥猪等日龄较长、体重较大生猪最早发病。养殖环节ASF发病场户内累积发病率为0.75%~88.24%,中位数为20.63%;病死率为21.26%~100%,中位数为100%。生猪调运是ASF跨区域传播的重要风险因素,车辆、人员的机械携带是病毒传入辽宁省养殖环节各疫点的主要途径。本研究对辽宁省进一步有效防控ASF提供了数据支持。

A total of 18 cases infected with African swine fever(ASF)had been reported in pig production link in Liaoning Province since August 2018 when the first case was found in China,involving 24 farms/households.In order to identify the epidemiological characteristics of these cases,the results of epidemiological investigation were descriptively analyzed,the distribution characteristics of time,space and population were presented,and the epidemiological indicators including incidence rate and mortality were calculated,so as to analyze the possible pathways by which the virus was introduced into farms/households.The outbreak of ASF could be traced back to the period between early June and middle June 2018,and the characteristics of time aggregation were shown from September to October 2018;the sows and fattening pigs with longer day-old and heavier weight were firstly infected;the cumulative incidence rates of ASF ranged 0.75%to 88.24%in the infected farms/households,with a median of 20.63%;and the fatality rates were 21.26%to 100%,with a median of 100%;ASF was mainly cross-regionally spread via the movement of pigs,and introduced into all infected premises of the province through the movement of vehicles and personnel.As a conclusion,the study provided some data for further effective prevention and control of ASF.