Diversity and transmission and zoonotic potential of microbes in true insectivores

The Eulipotyphla (true insectivores) is the third largest mammalian order, comprising over 500 species, and could be an important source of human infectious diseases. However, relatively little is known about the microbial diversity in insectivores and their contribution to virus transmission among wild hosts. In this study, we compile a comprehensive dataset containing over 400,000 records of insectivores and their associated microbes from 1903 to 2023 from multiple public databases. Meta-analyses show that insectivores host 941 unique microbes, 60% of which are viruses; these are predominantly found in shrews and hedgehogs. Human-associated viruses harbored by shrews and hedgehogs are phylogenetically closely related to those in humans, suggesting potential bidirectional transmission between insectivores and humans. Moreover, virus-sharing networks reveal that insectivores hold the second-most central position for virus sharing, second to bats, among all mammalian orders. Insectivores have a high proportion of cross-order transmitted viruses, including many human-associated viruses. Dietary diversity, habitat diversity, and distributional traits emerge as the key ecological factors contributing to cross-species virus transmission. Our findings highlight the microbial diversity in insectivores, indicating this order may serve as potential incubators for viruses capable of infecting mammals and spreading viruses of public health concern.