广东连平县存在新的蜱传斑点热立克次体

目的对采自广东省连平县的3种硬蜱进行蜱传斑点热立克次体检测分析。方法斑点热立克次体的ompA基因片段扩增并测定扩增片段的DNA序列。结果20只蜱分为17组,其中15组PCR检测阳性。对4个测序成功的标本进行聚类分析,证实其中3个序列单独聚为一类,与引起Flinders岛蜱传斑点热的弗诺立克次体(R.honei)、非洲蜱咬热的非洲立克次体(R.africa)、未定名斑点热的斯洛伐克立克次体(R.slovaca)以及西伯利亚立克次体BJ-90株等亲缘关系较近,另一序列与我国长白山地区检测到的JL-02具有较高的同源性。结论本研究提示该地区除了已证实的西伯利亚斑点热外,还存在新的蜱传斑点热。

The new tick-borne spotted fever group rickettsia exists in ticks from Lianping county of Guangdong province

Seventeen groups of ticks belonging to three different species were collected from Lianping county of Guangdong province.The ompA gene fragment,unique to the spotted fever group rickettsiae(SFGR),was amplified.Another three 16S rRNA genes were also amplified with genus-specific 16S rRNA genes of Ehrlichia.Coxiella burnetii,and the outer surface protein(OspA) gene of Borrelia burgdorferi.The DNA sequence of the amplified fragments were then determined.It was found that the carrier rate of SFGR in ticks was 88%,and the rate of compound infection was 17.6%.Of the four sequences of the ompA gene obtained,three were clustered into a single group that was close to R.honei,R.africa,R.slovaca and R.sibirica as revealed from the analysis of the phylogenetic tree,and all these rickettsiae except R.sibirica were emerging as the agents to cause infectious diseases as demonstrated by recent studies,in which R.honei and R.africa were considered to be an important threat to travelers throughout the world.Another sequence of ompA gene showed high homology with the JL-02 strain isolated from ticks captured in Changbai mountain area of Jilin province.From the above mentioned observations,it is evident that there exists new tick-borne spotted fever group rickettsia in this area except the definitely identified rickettsiae,thus emphasizing the importance on monitoring and differential diagnosis of the spotted fever disease in this area.