Abstract:

Objective To investigate rodents, chigger mites and Orientia tsutsugamushi on mountains and plain in Qing' an county. Methods Small mammals were trapped by snap traps in September, 2013. Rodents and their ectoparasites were collected and identified morphologically. Then the rodents were dissected under sterile conditions. DNA was extracted from the spleens, nested-PCR was performed to amplify and sequence the 56 kD type-specific antigen gene of O. tsutsugamushi from all samples collected in this area. Results A total of 107 small vertebrates including 9 species were captured. Apodemus agrarius was the predominant species in outdoor rural settlements and farmland. While Rattus norvegicus and Mus musculus were the predominant in indoor environment. Apodemus agrarius and Ap. peninsulae were the predominant species in forest areas. A total of 1 164 chigger mites were collected from small mammals, including Neotrombicula gardellai, Leptotrombidium orientalis, N. japonica, and L. subintermedium. Chigger mite index on M. rufocanus was highest (65.50), then T. triton (58.13), C. rutilus (22.86) and Eutamias sibiricus (24.00). No chigger mites were found in rural settlements and farmland far from forest. Orientia tsutsugamushi was detected from T. triton and Ap. peninsulae by nested-PCR. Conclusion The composition of the small mammals and chigger mites species is similar to those in the north of Northeast China. Orientia tsutsugamushi was firstly detected in rodents in the county. Therefore Qing' an is an new natural focus of scrub typhus and human infection should be investigated in the future.

Key words: Small mammals, Chigger mite, Orientia tsutsugamushi, Scrub typhus, 56 kD antigen gene

摘要：

目的 调查黑龙江省绥化市庆安县山地和平原地区小兽体表寄生恙螨和恙虫病东方体的感染情况。方法 于2013年9月利用夹夜法捕获小兽，鉴定种类并梳检小兽体表恙螨，对恙螨种类进行鉴定并计算恙螨指数；无菌解剖小兽肝、脾等脏器，低温保存，提取其DNA，采用巢氏PCR扩增恙虫病东方体56 kD表面蛋白基因。结果 共捕获小兽107只，包括啮齿目和食虫目共9种；农村居民区室外以黑线姬鼠为主，室内仅捕获褐家鼠和小家鼠；农田以黑线姬鼠为主，林区以黑线姬鼠和朝鲜姬鼠为主；小兽体表共检获1 164只恙螨，包括高丽新恙螨、东方纤恙螨、日本新恙螨和亚中纤恙螨；林区的棕背鼠平恙螨指数最高，为65.50，大仓鼠、红背鼠平和花鼠次之，分别为58.13、22.86和24.00；距林区较远的农田和居民区小兽体表未发现恙螨。山区大仓鼠和朝鲜姬鼠各1只经PCR恙虫病东方体核酸检测为阳性。结论 庆安县小兽及其体表恙螨种类与东北北部其他地区类似，鼠类中检出恙虫病东方体，该地区是新发现的恙虫病自然疫源地，应开展人群流行病学调查。

关键词: 小兽, 恙螨, 恙虫病东方体, 恙虫病, 56 kD表面蛋白