2009-2012年河北鼠型斑疹伤寒流行概况及实验室调查分析

目的 对2009-2012年河北省斑疹伤寒高发地区临床报告病例进行实验室调查分析。方法 按我国卫生部《流行性和地方性斑疹伤寒诊断标准》(WS 215-2008)在临床可疑病例高发地区设立哨点监测医院并收集病例。临床病例进行个案登记并进行发病急性期及恢复期血液标本的收集。实验室检测按WHO推荐的立克次体血清学诊断方法-间接免疫荧光法检测病人血清IgM和IgG特异抗体。以急性期血液DNA为模板,采用巢氏PCR扩增斑疹伤寒群立克次体热休克蛋白基因groEL基因并测序。通过NCBI Blast平台同源比较序列并使用DNA_STAR软件进行遗传进化分析。结果 本次调查在辛集市、定州市和迁安市共收集877例临床报告病例,2009年报告病例数最多(441例),迁安市病例数最多(510例)。急性期血清莫氏立克次体IgM抗体阳性率为 72.8%(73/101),IgG阳性率为 78.2%(79/101)。12人通过血清IgG抗体4倍升高或降低明确诊断。PCR扩增阳性率为21.7%(22/101),成功测序的17人groEL(209 bp)基因100%同源,与其他地区序列存在较大变异,与标准株R.typhi Wilmington (AY191590)核苷酸97.0%,氨基酸只有93.9%同源,进化分析与其他菌株遗传关系较远。结论 河北省辛集、定州和迁安地区存在鼠型斑疹伤寒流行。进一步调查传播媒介及宿主对该病的预防控制具有重要公共卫生意义。加强该病临床诊断及鉴别诊断十分必要。

Epidemiological characterizes and laboratory investigation of endemic typhus in Hebei Province, 2009-2012

In case of increasing the number of murine typhus cases from hospitals in Hebei Province, a joint investigation was conducted by the National Institute for Communicable Disease Control and Prevention, China CDC and Centers for Disease Control and Prevention of Hebei Province during 2009-2012. Based on the criteria of "Diagnostic criteria for epidemic typhus and endemic typhus (WS215-2008)" issued by Ministry of Health of The People's Republic of China on Feb 28, 2008, 877 clinical diagnostic cases were recruited from Xinji City, Dingzhou City and Qianan City and 101 blood samples from acute stage of illness and 17 blood samples from convalescence of illness were collected respectively, IgM and IgG antibodies against Rickettsia typhi in sera were tested by immunofluorescence assays (IFA). Nested PCR targeted R. typhi groEL gene was performed using acute stage blood clots DNA as temples and phylogenetic analysis was conducted based on the groEL gene. Epidemiological data indicated the highest annual incidence was 2009 with 441 cases and the highest areas were Qianan City with 510 cases. Of the acute phase sera, 72.8% (73/101) were IgM positive and 78.2% (79/101) were IgG positive. A 4-fold seroconversion in the IgG antibody titer was observed in 12 patients (4-fold increase in 7 patients and 4-fold decrease in 5 patients). The 21.7% (22/101) of acute stage blood clot DNA were nested PCR positive. Sequence analysis showed the partial sequence of groEL genes from 17 patients were 100% identity for each other. Compared with the reference stain R. typhi Wilmington (AY191590), only 97.0% of nucleotide homology and 93.9% amino acid homology were noticed and phylogenetic analysis indicated the groEL genes tested in the study were far from other sequences identified in other areas of the world. Here, we concluded that the reemerging murine typhus was confirmed in most areas of Hebei Province, China, and diagnosis and differential diagnosis of the R. typhi infection should be emphasized in hospitals.