云南省保山市一起地方性斑疹伤寒暴发的调查

An outbreak of endemic typhus in Baoshan city, Yunnan province

目的 了解云南省保山市一起地方性斑疹伤寒暴发的流行病学特征.方法 收集患者的流行病学资料.应用外斐反应和间接免疫荧光方法同时检测患者血清中莫氏立克次体、恙虫病东方体IgG抗体.用PCR检测鼠类脾脏标本中莫氏立克次体、普氏立克次体gltA基因,恙虫病东方体56kDa蛋白基因,斑点热群立克次体ompA基因,埃立克体16S rRNA基因和无形体16SrRNA基因.结果 2009年7-8月保山市隆阳区该起地方性斑疹伤寒累计发病58例,其中48例为临床诊断病例,10例为实验室诊断病例.3例地方性斑疹伤寒实验室诊断病例存在Karp型恙虫病东方体感染.PCR检测黄胸鼠脾脏85份,其中莫氏立克次体gltA片段阳性3份（阳性率为3.5%）,其序列与莫氏立克次体Wilmington株（GenBank U59714.1）同源性为100%;普氏立克次体、恙虫病东方体、斑点热群立克次体、无形体和埃立克体均为阴性.结论 经流行病学、临床资料和实验室检测证实,保山市隆阳区该起疫情为地方性斑疹伤寒.从当地优势鼠种黄胸鼠中检测到莫氏立克次体核酸及序列,表明当地存在地方性斑疹伤寒疫源地.

Objective To understand the epidemiologic characteristics of endemic typhus in Baoshan city. Methods Epidemiological data were collected and characteristics were analyzed. IgG antibody（Ab） of Rickettsia mooseri and Orientia tsutsuganushi in serum of patients were tested using both Weil-Felix and IFA method. The Rickettsia mooseri gltA gene, Rickettsia prowazekii gltA gene,Orientia tsutsugamushi 56 kDa protein gene, SFGR ompA gene, Ehrlichia sp. 16S rRNA gene and Anaplasma sp. 16S rRNA gene in spleen of mice were examined by PCR. Results Fifty- eight endemic typhus cases were found in Longyang district of Baoshan city, during July to August, 2009.Among them, 48 cases were confirmed by clinical diagnosis and 10 cases by laboratory tests. The Ab of Orientia tsutsugamushi Karp serotype was detected in 3 cases from laboratory diagnosis. The spleen samples from 85 Rattns flavipectus were tested using PCR. Of them, 3 samples for Rickettsia mooseri gltA gene showed positive （positive rate was 3.5% ）, and the homology of 3 Rickettsia mooseri and Rickettsia mooseri Wilmington strain （GenBank U59714.1） was 100% through comparing gene sequence. The results of PCR for detecting Rickettsia prowazekii, Orientia tsutsugamushi, SFGR,Anaplasma sp. and Ehrlichia. sp were all negative. Conclusion The outbreak of endemic typhus was confirmed in Longyang district of Baoshan city through epidemiological data, clinical diagnosis and laboratory tests. Rickettsia mooseri DNA was detected in the dominant Raw flavipectus, suggesting that endemic typhus did exist in the local areas.