西北新疆等4省区蜱感染菜姆病螺旋体的分子流行病学调查

摘要

目的 了解我国西北部分省区蜱中莱姆病螺旋体感染及其基因分型情况.方法 应用巢式PCR扩增脾中莱姆病螺旋体5S-23S rRNA间隔区片段,对阳性产物进行限制性片段长度多态性(RFLP)分析.结果 共检测11个蜱种2 460只,感染莱姆病螺旋体的有11个种304只,阳性率为12.36%.新疆、宁夏、陕西、甘肃的感染率分别为11.31%、17.96、12.35%及11.64%.不同省区阳性率存在差别;不同蜱种间阳性率亦存在明显差别,其中以青海血蜱阳性率最高,达到59.38%.RFLP分析结果显示西北四省区蜱中莱姆病螺旋体为B.garinii及B.afzelii基因型,其中B.garinii基因型为主要基因型,占80%以上.结论 莱姆病螺旋体在我国西北4省区中广泛存在,存在B.garinii及B.afzelii两种基因型.%In order to investigate Boreliaferii infection in vectors captured in some areas of Northwestern China and to identify the genotypes, ticks were collected to conduct species identification, and DNA was isolated from ticks and detected by nested PCR targeting 5S-23S rRNA intergenic spacer of B.ferii.Positive samples were further analysed by restriction fragment length polymorphism (RFLP).A total of 2 460 ticks, which including 11 species, were detected for evidence of B.ferii by nested PCR.And 304 samples showed positive result, the average positive rate in ticks was 12.36％.The positive rates in Xinjiang, Ninxia, Shanxi and Gansu were 11.31 ％, 17.96, 12.35％ and 11.64 ％, respectively.The positive rates were significantly different among different tick species and different provinces with Haemaphysalis qinghaiensis, and Ninxia Province had highest positive rate.RFLP analysis indicated that B.ferii in ticks belonged to either B.garinii or B.afzelii.Infection of B.ferii exists in nature among tick vectors in Northwestern China, and there are at least two genotypes.