云南省部分地区地里纤恙螨分布调查

Preliminary survey on the distribution of Leptotrombidium deliense in some areas of Yunnan province

目的 探讨云南省地里纤恙螨在宿主选择及在不同地域的分布情况.方法 选择云南省部分县（市）进行现场调查,用鼠笼加食饵诱捕小兽,收集其双侧耳廓和外耳道的恙螨幼虫,用Hoyer＇s液封片后在显微镜下逐一分类鉴定到种.统计不同恙螨种类、构成比及其在对应寄生宿主的感染率（染螨率）和感染度（螨指数）,分析其在不同宿主体表和不同地域的分布情况.结果 在调查的19个县（市）共捕获小兽10 222只,在其体表采集到92 990只恙螨,经分类鉴定隶属于3亚科22属225种.其中采集到地里纤恙螨共1544只,仅占所有恙螨的1.659%;且宿主特异性低,仅在调查点的6个县（市）的19种8518只小兽体表采集到.结论 历史上认为地里纤恙螨是云南省恙虫病流行区优势螨种和主要媒介可能只是某些局部地区的情况,不同地域生境的恙螨构成和优势螨种可能存在差别.

Objective To investigate the distribution of Leptotrombidium deliense among different small mammal hosts in some areas of Yunnan province. Methods A field survey was carried out in some counties of Yunnan province and the small mammal hosts were captured, using mouse cages and traps with baits. Chigger mites on the surface of two auricles were scraped off by a bistoury, and then preserved in 70% ethanol. Every specimen of the chigger mites on the slides was finally identified into species under a microscope. Some conventional statistical methods were adopted to calculate all the collected chigger mite species and the constituent ratios of Leptotrombidium deliense in different areas and on different hosts, together with its prevalence and mean abundance on different hosts. Results A total of 10 222 small mammal hosts were captured from 19 counties and identified as 11 families, 34 genera and 62 species in 5 orders, and 92 990 individuals of chigger mites were collected from the body surface of these small mammal hosts. All the collected chigger mites were identified as 3 subfamilies, 22 genera, and 225 species. Meanwhile, Leptotrombidium deliensee only accounted for 1.659% of the total. The host specificity of Leptotrombidium deliense was very low and 1544 individuals of Leptotrombidium deliense collected from 8518 small mammal hosts belonged to 6 families, 13 genera and 19 species in 3 orders. Our results showed that Leptotrombidium delienses were mainly collected from Insectivora and Rodentia. Leptotrombidium deliense had long been considered as the dominant species of chigger mites and the main vector of tsutsugamushi disease in Yunnan province of China, but our results seemed not thoroughly supporting this point of view. Conclusion Traditionally, Leptotrombidium deliense was the dominant species and the main vectors of scrub typhus in Yunnan province. However, based on our results, the above view might be true in some local places and the composition of chigger mites and the main vector of tautsugamushi disease might be different in regions and habitats in Yunnan province.