2016-2018年陕西省炭疽监测及基因溯源分析

目的 调查了解2016-2018年陕西省炭疽流行情况、病原学特征及分子流行病学特征。方法 对2016-2018年报告炭疽病例开展个案调查,进行流行病学三间分布分析;采集病例生物样本及环境样本,进行炭疽杆菌分离培养、炭疽ELISA抗体检测及荧光定量PCR检测,对分离到的阳性标本以canSNP及MLVA15的方法进行分子分型,与陕西省历史菌株及国内部分省份菌株基因型进行聚类分析。结果 2016-2018年陕西省共炭疽病例14例,发病到诊断平均9天,地理分布以关中及陕北地区为主,8月份发病较多,人群分布性别比为6∶1(12/2),26~59岁占85.7%(12/14),农民占71.4%(10/14)。人体标本病原培养17份,分离到炭疽杆菌1株,阳性5.9%,环境标本培养77份均为阴性,ELISA检测阳性率83.3%(10/12),荧光定量PCR阳性率21.4%(3/14);陕西省炭疽菌株canSNP基因型为A.Br.001/002型,2015年、2018年及1953年菌株MLVA分型分别为MLVA15-38、31、CHN17基因型。结论 2016-2018年陕西省炭疽疫情属较低散发水平,主要分布在关中及陕北地区,8月为发病高峰,人群以青壮年男性农民为主。炭疽杆菌canSNP基因型为A.Br.001/002,与国内主要流行株相同。存在3种不同的MLVA15基因型。陕北地区MLVA15-38型,与北部内蒙古相近;关中地区MLVA15-31型,与甘肃省及新疆类似;历史上还曾有MLVA15-CHN17型。

Surveillance and gene tracing of anthrax in Shaanxi,2016-2018

Objective To investigate the epidemic situation,etiological characteristics and molecular epidemiological characteristics of anthrax in Shaanxi Province from 2016 to 2018.Methods We used case investigation of anthrax cases reported in 2016-2018 and epidemiological analysis of spatial,temporal and population distribution.Biological samples and environmental samples were collected for B.anthracis isolation culture,anthrax ELISA antibody detection and real-time PCR detection.The positive samples were molecularly typed by canSNP and MLVA15,and clustered with the historical strains of Shaanxi Province and the genotypes of some domestic provinces.Results A total of 14 cases were reported from 2016 to 2018 in Shaanxi Province.The average time from onset to diagnosis was 9 days.The geographical distribution was mainly in Guanzhong and Northern Shaanxi.There were more cases in August.The sex ratio of population distribution was 6:1(12/2).85.7%(12/14)were 26-59 years old,and 71.4%(10/14)were peasants.One strain of Bacillus anthracis was isolated from 17 human specimens,and the positive rate was 5.9%.77 environmental specimens were negative.The positive rate of ELISA was 83.3%(10/12).The positive rate of fluorescence quantitative PCR was 21.4%(3/14).CanSNP genotype of anthrax strain in Shaanxi Province was A.Br.001/002.MLVA genotypes of strains isolated in Shaanxi Province in 2015,2018 and 1953 were MLVA15-38,31 and CHN17 genotypes,respectively.Conclusion The anthrax epidemic in Shaanxi Province in 2016-2018 is at a low emission level.The cases are mainly distributed in Guanzhong and Northern Shaanxi.August is the peak incidence.The distribution of the population is dominated by young male farmers.The canSNP genotype A.Br.001/002 of Bacillus anthracis in Shaanxi Province is the same as that of the main domestic strains,and there are three different MLVA15 genotypes.MLVA15-38 in Northern Shaanxi is similar to Inner Mongolia.MLVA15-31 in Guanzhong is similar to Gansu Province and Xinjiang Province.There have also been MLVA15-CHN17 models in history.