云南横断山中部山区小型兽类感染巴贝虫的分子流行病学调查

Molecular epidemiological investigation of Babesia infection in small mammals in the central Hengduan Mountains of Yunnan Province

为了解云南省横断山中部山区小型兽类感染巴贝虫的情况,分别于2013、2016和2020年在云南省横断山中部山区的剑川、云龙和洱源等3个县,采用笼日法和夹线法捕获小型兽类。通过形态学进行种类鉴定,并取脾组织,提取巴贝虫DNA,巢式PCR扩增巴贝虫18S r RNA基因片段,目的条带经双向测序后,进行同源性分析,采用Neighbor-Joining法构建系统进化发育树。共捕获小型兽类498只,通过形态学鉴定,分属于4目8科14属27种,主要优势鼠种有齐氏姬鼠、中华姬鼠和大绒鼠,共有55份样品扩增出巴贝虫18S r RNA基因片段,总阳性率为11%(55/498)。剑川县、云龙县和洱源县的小型兽类巴贝虫阳性率分别为0.5%(1/212)、31.6%(54/171)和0(0/115)。巴贝虫阳性检出率比较高的小兽为:大耳姬鼠11/17,滇绒鼠5/10,印度长尾鼩鼱2/4。BLAST比对结果表明,本次检出的样品序列具有高度同源性,相似性达99.6%,属于田鼠巴贝虫的大津(Otsu)型。云南省横断山中部山区小型兽类存在巴贝虫感染,属于田鼠巴贝虫的Otsu型。

To understand the situation of infection with Babesia spp. in small mammals in the middle part of mountainous area of Hengduan Mountain of Yunnan Province, small mammals were captured by trap rows and cages(in the daytime) in Jianchuan, Yunlong and Eryuan counties of the area in 2013, 2016 and 2020. The species of the captured animals was identified by morphology, and DNA was extracted from the spleen tissues. The18 S r RNA gene fragment of Babesia spp. was amplified by nested PCR. After bidirectional sequencing, the targeted bands were analyzed for homology. The phylogenetic tree was constructed by the Neighbor-Joining method. A total of498 small mammals were captured, including 212 in Jianchuan County, 171 in Yunlong County and 115 in Eryuan county. They were morphologically identified of 27 species, belonging to 14 genera, 8 families of 4 orders. The dominant rodent species included Apodemus chevrieri, A. draco and Eothenomys miletus. The 18 S r RNA gene fragment of Babesia spp. was amplified from 55 samples, with an overall positive rate of 11%(55/498). The positive rate in Jianchuan County, Yunlong County and Eryuan County was 0.5%(1/212), 31.6%(54/171) and 0(0/115),respectively. The detection rate was relatively high in A. latronum(11/17), E. elegusis(5/10) and Soriculus leucops(2/4). The results of BLAST analysis showed that the sequences amplified in the samples were highly homologous(similarity 99.6%) and belong to the Otsu type of B. microti. There was Babesia infection in small mammals in the mid-mountainous area of Hengduan Mountain, Yunnan Province, the Babesia belonging to the Otsu type of B. microti.