Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
Scripps Institution of Oceanography, University of California San Diego, La Jolla, CA, USA.
Mol Ecol. 2022 Apr;31(7):1939-1950. doi: 10.1111/mec.16044. Epub 2021 Aug 2.
Skin is the largest mammalian organ and the first defensive barrier against the external environment. The skin and fur of mammals can host a wide variety of ectoparasites, many of which are phylogenetically diverse, specialized, and specifically adapted to their hosts. Among hematophagous dipteran parasites, volatile organic compounds (VOCs) are known to serve as important attractants, leading parasites to compatible sources of blood meals. VOCs have been hypothesized to be mediated by host-associated bacteria, which may thereby indirectly influence parasitism. Host-associated bacteria may also influence parasitism directly, as has been observed in interactions between animal gut microbiota and malarial parasites. Hypotheses relating bacterial symbionts and eukaryotic parasitism have rarely been tested among humans and domestic animals, and to our knowledge have not been tested in wild vertebrates. In this study, we used Afrotropical bats, hematophagous ectoparasitic bat flies, and haemosporidian (malarial) parasites vectored by bat flies as a model to test the hypothesis that the vertebrate host microbiome is linked to parasitism in a wild system. We identified significant correlations between bacterial community composition of the skin and dipteran ectoparasite prevalence across four major bat lineages, as well as striking differences in skin microbial network characteristics between ectoparasitized and nonectoparasitized bats. We also identified links between the oral microbiome and presence of malarial parasites among miniopterid bats. Our results support the hypothesis that microbial symbionts may serve as indirect mediators of parasitism among eukaryotic hosts and parasites.
皮肤是哺乳动物最大的器官，也是抵御外部环境的第一道防线。哺乳动物的皮肤和皮毛可以寄生各种各样的外寄生虫，其中许多寄生虫在系统发育上是多样的、专门的，并专门适应它们的宿主。在吸血双翅目寄生虫中，挥发性有机化合物 (VOC) 已知是重要的引诱剂，引导寄生虫寻找合适的血液来源。VOC 被认为是由宿主相关细菌介导的，这些细菌可能会间接影响寄生虫病。宿主相关细菌也可能直接影响寄生虫病，正如在动物肠道微生物群与疟原虫寄生虫之间的相互作用中观察到的那样。关于细菌共生体和真核寄生虫之间的假说在人类和家畜中很少被测试，据我们所知，在野生脊椎动物中也没有被测试过。在这项研究中，我们使用了非洲蝙蝠、吸血外寄生虫蝙蝠蝇和由蝙蝠蝇传播的血孢子虫（疟原虫）寄生虫作为模型，以测试宿主微生物组与野生系统中寄生虫病之间存在联系的假说。我们在四个主要蝙蝠谱系中发现了皮肤细菌群落组成与双翅目外寄生虫流行率之间的显著相关性，以及外寄生虫感染和非外寄生虫感染蝙蝠之间皮肤微生物网络特征的显著差异。我们还在迷你蝠科蝙蝠中发现了口腔微生物组与疟原虫寄生虫存在之间的联系。我们的研究结果支持这样一种假说，即微生物共生体可能是真核宿主和寄生虫之间寄生虫病的间接介导者。
