Abstract:

Objective To understand the status of Orientia tsutsugamushi infection in Pinggu district, Beijing. Methods Nested?PCR（nPCR）was employed to amplify and sequence the groEL gene and 56×103 protein of O. tsutsugamushi from 30 samples collected in the district, with indirect immunofluorescence assay (IFA) used for the detection of the specific antibody to O. tsutsugamushi in the serum samples. Results There was a positive rate of 100% in terms of the gene and protein in the 30 blood samples tested with PCR, and 25 of the 28 serum samples that were tested by indirect immunofluorescence assay were found to be positive for the antibody, accounting for 89.3%. There were 3 samples that were positive with long fragment PCR amplification and DNA sequencing revealed that the sequences from all the samples were identical with a homology of 96% with Kawasaki type. Conclusion The existence of scrub typhus in Pinggu district of Beijing was for the first time confirmed from the perspective of molecular epidemiology and seroepidemiology. Our study indicates that physicians need pay attention to scrub typhus in febrile patients living in northern China where scrub typhus was not considered present in the past.

Key words: Scrub typhus, nested?PCR, Immunofluorescence assay

摘要：

目的 了解北京市平谷地区是否存在恙虫病东方体感染。方法 采用巢式聚合酶链反应(nPCR)，对平谷地区采集的30份临床标本进行恙虫病东方体热休克蛋白(groEL)基因和56×103蛋白扩增并测序分析。采用间接免疫荧光试验(IFA)对血清标本恙虫病东方体特异抗体检测。结果 采用PCR共检测血液标本30份，均阳性(100%); 用IFA检测28份患者血清抗体，25份阳性(89.3%); 长片段PCR扩增，3份标本扩增阳性，阳性结果测序比对所有核苷酸序列相同，与Kawasaki的同源性为96%。结论 首次从分子流行病学和血清流行病学的角度证实北京平谷地区存在恙虫病东方体。

关键词: 恙虫病, 巢式聚合酶链反应, 间接免疫荧光试验