Zhan Y-Z, Guo X-G, Speakman J R, Zuo X-H, Wu D, Wang Q-H, Yang Z-H
Vector Laboratory, Institute of Pathogens and Vectors, Dali University, Dali, Yunnan, China.
Med Vet Entomol. 2013 Jun;27(2):194-202. doi: 10.1111/j.1365-2915.2012.01053.x. Epub 2012 Nov 20.
This paper reports on ectoparasitic chigger mites found on small mammals in Yunnan Province, southwest China. Data were accumulated from 19 investigation sites (counties) between 2001 and 2009. A total of 10 222 small mammal hosts were captured and identified; these represented 62 species, 34 genera and 11 families in five orders. From the body surfaces of these 10 222 hosts, a total of 92 990 chigger mites were collected and identified microscopically. These represented 224 species, 22 genera and three subfamilies in the family Trombiculidae (Trombidiformes). Small mammals were commonly found to be infested by chigger mites and most host species harboured several species of mite. The species diversity of chigger mites in Yunnan was much higher than diversities reported previously in other provinces of China and in other countries. A single species of rodent, Eothenomys miletus (Rodentia: Cricetidae), carried 111 species of chigger mite, thus demonstrating the highest species diversity and heaviest mite infestation of all recorded hosts. This diversity is exceptional compared with that of other ectoparasites. Of the total 224 mite species, 21 species accounted for 82.2% of all mites counted. Two species acting as major vectors for scrub typhus (tsutsugamushi disease), Leptotrombidium scutellare and Leptotrombidium deliense, were identified as the dominant mite species in this sample. In addition to these two major vectors, 12 potential or suspected vector species were found. Most species of chigger mite had a wide range of hosts and low host specificity. For example, L. scutellare parasitized 30 species of host. The low host specificity of chigger mites may increase their probability of encountering humans, as well as their transmission of scrub typhus among different hosts. Hierarchical clustering analysis showed that similarities between different chigger mite communities on the 18 main species of small mammal host did not accord with the taxonomic affinity of the hosts. This suggests that the distribution of chigger mites may be strongly influenced by the environment in which hosts live.
本文报道了在中国西南部云南省小型哺乳动物身上发现的外寄生恙螨。数据收集于2001年至2009年间的19个调查地点（县）。共捕获并鉴定了10222只小型哺乳动物宿主；它们分属于5目11科34属62种。从这10222只宿主的体表，共收集到92990只恙螨，并通过显微镜进行了鉴定。这些恙螨分属于恙螨科（真螨目）的224种、22属和3个亚科。常见小型哺乳动物身上寄生有恙螨，且大多数宿主物种身上都寄生有几种恙螨。云南恙螨的物种多样性远高于此前中国其他省份以及其他国家所报道的多样性。一种啮齿动物，大绒鼠（啮齿目：仓鼠科），身上携带有111种恙螨，这显示出其为所有记录宿主中物种多样性最高且螨类寄生最为严重的。与其他外寄生虫相比，这种多样性非常突出。在总共224种螨类中，21种占所有计数螨类的82.2%。鉴定出作为恙虫病（丛林斑疹伤寒）主要传播媒介的两种恙螨，小板纤恙螨和地里纤恙螨，为该样本中的优势螨种。除了这两种主要传播媒介外，还发现了12种潜在或疑似传播媒介物种。大多数恙螨物种宿主范围广泛且宿主特异性较低。例如，小板纤恙螨寄生于30种宿主。恙螨较低的宿主特异性可能会增加它们接触人类的概率，以及它们在不同宿主间传播恙虫病的可能性。层次聚类分析表明，18种主要小型哺乳动物宿主身上不同恙螨群落之间的相似性与宿主的分类亲缘关系不一致。这表明恙螨的分布可能受到宿主生活环境的强烈影响。
