云南部分地区鼠类及媒介昆虫自然感染立克次体调查

Investigation on rickettsiae natural infection in mice and vector arthropods in partial areas of Yunnan

目的了解云南地区宿主动物和媒介自然感染立克次体的情况。方法采用鼠夹和鼠笼捕鼠,采集鼠体表的恙螨和耕牛体表的蜱虫,对鼠脾脏、恙螨和蜱虫提取DNA,应用巢式PCR扩增立克次体gro EL基因,基因序列测定后与其它已知序列进行同源性分析。结果从410份样品中扩增出立克次体gro EL片断19份(阳性率4. 63%),其中恙虫病东方体(Ot)阳性率2. 68%(11/410),斑点热立克次体(SFGR)阳性率1. 22%(5/410),莫氏立克次体(Rm)阳性率0. 49%(2/410),立克次体共生菌(Re)阳性率0. 24%(1/410)。与其它已知序列进行同源性分析,检出11株Ot的相似性为93. 6%～100%,分别与Gen Bank中已知立克次体序列的最高相似性在96. 1%～100%;检出5株SFGR相似性为92. 1%～99. 5%,分别与Gen Bank中已知序列的最高相似性在98. 9%～100%;检出Rm 2株,均与Wilmington株的相似性达100%;检出Re 1株,与Re(EU435143)的相似性最高为98. 9%。结论云南地区宿主动物及媒介中存在多种立克次体感染,应加强立克次体病的监测与防制工作。

Objective To investigate rickettsiae infection from host animals and vector arthropods in some areas of Yunnan Province.Methods Rat clip and cage traps were used to capture mice.Chiggers from body surface of mice and ticks from body surface of farm cattle were collected.DNAs were extracted from mice spleens,chiggers and ticks.Rickettsiae groEL segment were amplified by nested-polymerase chain reaction(nPCR),sequenced to analyze the homology with other known sequences.Results A total of 410 samples were collected for rickettsiae groEL segment detection with nPCR and 19 samples(4.63%)showed positive for rickettsiae groEL segment.Among them,2.68%(11/410)were positive for Orientia tsutsugamsushi(Ot)groEL segment,and 1.22%(5/410)were positive for spotted fever group rickettsia(SFGR)groEL segment,and 0.49%(2/410)were positive for rickettsia mooseri(Rm)groEL segment,and 0.24%(1/410)were positive for rickettsia endosymbiont(Re)groEL segment.When analyzed the homology with other known sequences,11Ot strains with 93.6%-100%similarities among them in this study shared the highest similarity with other Ot strains from GenBank respectively,reached up to 96.1%-100%;The groEL segments of 5 SFGR strains with 92.1%-99.5%similarities among them in this study shared highest similarity with other SFGR strains from other GenBank respectively,reached up to 98.9%-100%;In this study groEL segments of 2 Rm strains all showed 100%similarity with Wilmington strain(GenBank No:AE017197);One groEL segment of Re showed 98.9%similarity with Re strain(GenBank No:EU435143).Conclusion There were kinds of rickettsiaes infection in host animals and vector arthropods in Yunnan Province,so the monitoring and prevention of the Rickettsiosis should be strengthened.