秦皇岛市鼠立克次体感染分子流行病学研究

A study on molecular epidemiology of Rickettsia murinus infection in Qinhuangdao City

目的 了解河北省秦皇岛市鼠立克次体感染情况,并分析感染菌株遗传进化特征。方法 选用粘鼠板和鼠笼在秦皇岛市北戴河区、海港区、青龙县进行捕鼠,解剖获得鼠脾脏,并提取其DNA,运用半巢氏PCR方法扩增鼠立克次体的ompA基因,对扩增阳性的产物分别测序,所得基因序列进行同源性比较,并进行系统发生分析。结果 秦皇岛市3个区县共捕鼠100只,阳性6只,立克次体阳性率为6.0%,其中北戴河区、青龙县阳性率为2.0%和4.0%,2者的阳性率差异无统计学意义(χ^(2)=2.128,P=0.345);不同鼠种比较显示,仅黑线姬鼠检出立克次体,检出率为9.2%。同源性分析结果显示,本研究获得的6株立克次体与劳氏立克次体的同源性最高。系统发生分析结果显示,秦皇岛市鼠携带的劳氏立克次体株与我国大部分地区的劳氏立克次体位于同一分支。结论 秦皇岛市鼠存在劳氏立克次体的感染,市民存在感染该类疾病的风险,相关部门应有针对性的加强秦皇岛市人群立克次体感染的风险监测。

Objective To investigate the infection status of Rickettsia murinus in Qinhuangdao City of Hebei Province, and to analyze the genetic evolution characteristics of the infected strains.Methods The rodents were captured with sticky boards and cages in Beidaihe District, Haigang District and Qinglong County of Qinhuangdao City.Their spleens were dissected and their DNAs were extracted. The ompA gene of Rickettsia murinus were amplified by semi-nested PCR,and the positive fragments amplified by the PCRs were sequenced.The obtained gene sequences were compared for homology and phylogenetic analysis.Results A total of 100 rodents were captured in 3 districts and counties of Qinhuangdao City, and 6 were positive, and the positive rate of Rickettsiae was 6.0%.The positive rate of Beidaihe County and Qinglong County were 2.0% and 4.0% respectively, and the differences between them was not statistically significant(χ^(2)=2.128,P=0.345).The comparison of different species showed that Rickettsia was detected only in Apodemus agrarius,with a detection rate of 9.2%.The homology analysis showed that the six Rickettsia strains obtained in this study had the highest homology with Rickettsia laurenii.The results of phylogenetic analysis showed that the Rickettsia laurenii strain carried by mice in Qinhuangdao City was in the same branch as Rickettsia laurenii in most areas of China.Conclusion Rickettsia laurenii infection exists in mice in Qinhuangdao City, and citizens are at risk of this disease.Relevant departments should strengthen the risk monitoring of Rickettsia infection in Qinhuangdao City.