2013—2014年泰州市恙虫病流行区疫源地的研究

Study of epidemic area on Tsutsugamushi disease in Taizhou from 2013 to 2014

目的 研究泰州市恙虫病流行特征,并判断泰州市是否存在该疾病的疫源地.方法 于2013—2014年,选择泰州市所属的靖江市新桥镇卫生院和东兴镇卫生院作为患者标本的采集场所,采集经临床诊断为恙虫病的急性期患者血液标本5 ml,共采集40份,用于核酸提取和分离培养.采用笼夜法于2013年5、7、9、10、11月在调查地点开展鼠类储存宿主的调查,共捕获鼠类59只,取其脾、肝、肾标本,置入相应编号的无菌冻存管;采用小黑板法和从鼠耳中捕获恙螨,共布放小黑板226板块,捕获螨27只,并将标本经研磨制成悬液.采用PCR法和细胞及组织培养法对恙虫病急性期患者、宿主动物和媒介恙螨进行恙虫病东方体核酸检测和分离培养.结果 40份急性期恙虫病患者全血标本中,29份符合检测要求,其中17份标本恙虫病东方体核酸呈阳性,阳性率59%,1份标本分离出恙虫病东方体.捕获鼠类59只,鼠密度为5.5%,其中小家鼠26只（鼠密度为2.4%）、黄胸鼠18只（鼠密度为1.7%）、臭鼩鼱15只（鼠密度为1.4%）.1只臭鼩鼱标本经检测,恙虫病东方体核酸呈阳性,其他鼠形动物标本细胞培养结果均为阴性.采用小黑板法共捕获螨27只,螨密度为0.12只/板,其中幼虫3只,若虫24只;从3只臭鼩耳中捕获恙螨33只,螨密度为11只/鼠.经鉴别,所有螨种均为小盾纤恙螨,1组来自于外环境的恙螨标本的核酸检测结果呈阳性.结论 泰州市恙虫病流行区5—11月期间存在较高的鼠密度,恙螨的螨种为小盾纤恙螨,急性期恙虫病患者、鼠形动物和媒介恙螨中均检出恙虫病东方体核酸,结合上述流行病学特征认为泰州市恙虫病流行区存在恙虫病自然疫源地.

Objective To study the epidemiological characteristics of tsutsugamushi disease, and to confirm the existence of the disease＇s epidemic foci in Taizhou. Methods From 2013 to 2014, Dongxing town hospital and Xingqiao town hospital were selected as specimen collection sites in Jingjiang city. Blood samples （5 ml） were collected from 40 patients with acute tsutsugamushi disease. A total of 59 rodents were captured with cage night method in the survey sites at 5, 7, 9, 10, and 11 months in 2013, from which, the spleen, liver, and kidney specimens were selected. Chigger mites were captured by small blackboard method and from the ears of the captured rodents. A total of 226 small blackboards were laid, 27 mites were captured, and the samples were grounded into suspension. Nested-polymerase chain reaction and cell and tissue culture techniques were used to test the specimen from the probable patients, host animals and chigger mites. Results Among the 40 acute tsutsugamushi disease blood samples, 29 were found to meet the test requirements, 17 were positive for orientia tsutsugamushi nucleic acid with 59%of the positive rate, and 1 stran orientia tsutsugamushi was isolated. 59 rats were captured and the density of mice was 5.5%. Among them, there were 26 Mus musculus （2.4%）, 18 Rattus flavipectus （1.7%） and 15 Smelly shrew （density 1.4%）. 1 Smelly shrew was tested positive for orientia tsutsugamushi nucleic acid, and the negative results were found in the other rodent specimens. 27 Chigge mites were collected by small blackboard method and the density of mites was 0.12 for each blackboard, among which 3 larvae and 24 nymphs were found. 33 Chigger mites were collected from the ears of 3 Smelly shrew, and the density of the mite was 11 per mouse. All the captured Chigger mites were identified as Leptotrombidium scutellare and 1 group of specimens of Chigger mites from the external environment were positive for orientia tsutsugamushi nucleic acid. Conclusion There was a high density of mice in the epidemic area from May to November and the species of the chigger mites were Chigger mites in Taizhou. The nucleic acid of the oriental tsutsugamushi was detected in the patients with acute scrub typhus, rodents and vectors. According to the above-mentioned results, it was considered that the scrub typhus epidemic area of Taizhou city has the natural foci of scrub typhus.