于氏纤恙螨在云南省部分地区的分布及宿主选择

Distribution and Host Selection of Leptotrombidium yui in Some Areas of Yunnan Province

目的:对于氏纤恙螨在云南省部分地区的分布和宿主选择情况进行初步探讨。方法:结合云南省不同地理方位和地形,独特的气候与生态等特点,于2001年—2011年选取了23个县(市)进行野外调查,用鼠笼(夹)加食饵诱捕鼠类等小型哺乳动物(小兽)宿主。选择小兽的双侧耳廓和外耳道采集恙螨幼虫,用霍氏液常规封片后在显微镜下逐一鉴定螨种。统计于氏纤恙螨在不同地域、不同景观和不同宿主小兽体表的分布情况。计算于氏纤恙螨在不同宿主小兽体表的感染率(P)、平均多度(MA)和感染度(MI),用聚块指数(m*/m)测定其在宿主不同个体间的空间分布格局。结果:所调查的23个县(市)中,有9个县(市)采集到了于氏纤恙螨(共1 959只,占所有恙螨的1.81%)。88.77%的于氏纤恙螨采自山区地理景观(尤其是海拔较高地区),只有11.23%的于氏纤恙螨采自坝区景观。宿主大类选择显示,采自啮齿目(鼠类)、攀鼩目(树鼩)和食肉目小兽体表的于氏纤恙螨分别为57.78%、42.16%和0.05%,其它目小兽体表没有采集到该螨。宿主种类选择显示,所捕获的5目12科34属67种小兽中,有20种小兽采集到了于氏纤恙螨,其中42.16%采自攀鼩目树鼩科树鼩属的树鼩,其感染率(26.52%)和感染度(13.54只螨/每兽)均比较高,其次是其他野栖小兽。聚块指数显示,于氏纤恙螨在大多数宿主小兽不同个体间的分布呈聚集分布格局。结论:云南省存在于氏纤恙螨,且数量较大。该螨主要分布在海拔较高的山区地带,可寄生多种小兽宿主,宿主特异性低,但主要倾向于寄生在树鼩等野栖小兽体表。

Objective： To investigate the geographical distribution and host selection of Leptotrombidium yui among different small mammal hosts in some areas of Yunnan province. Methods： A field survey was carried out in 23 counties of Yunnan province between 2001 and 2011. The small mammal hosts were captured with mouse cages and traps with baits. The 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 L. yui in different areas and on different hosts, together with its prevalence （P）, mean intensity （MI） and mean abundance （MA） on different hosts. The patch index （m＊/m） was used to measure the spatial patterns of L. yui among the different individuals of its small mammal hosts. Results： A total of 108 480 individuals of chigger mites were collected from the body surface of all the captured small mammal hosts. All the collected chigger mites were identified as 3 subfamilies, 24 genera and 234 species. Of 234 species of chigger mites, 1 959 individuals of L, yui were collected only in 9 counties. The collected individuals of L. yui accounted for 1.81% of the total mites （ 108 480 individuals）. 88.77% of L. yui came from the mountainous regions and habitats while only 11.23% of L. yui from flatland areas. The hosts in orders Rodentia and Scandentia harbored 57.78% and 42.16% of the collected L. yui. Of 67 species （in 34 genera and 12 families of 5 orders）, Tupaia belangeri （in Order Scandentia） harbored 42.16% of the collected L. yui with relatively high prevalence （P=26.52%） and mean intensity （MI=13.54 mites / per host）, and other wild-dwelling small mammals came next. The patch index showed that L. yui had an aggregated distribution pattern among different individual of their hosts. Conclusion： L. yui exists in Yunnan province with relatively a considerable number of individuals. In Yunnan province, L. yui is mainly distributed in the mountainous regions and habitats with relatively high altitude. L. yui can parasitize several different species of hosts with low host specificity, but it prefers to choose Tupaia belangeri and other wild-dwelling small mammals as its main hosts.