Network analysis of host–virus communities in bats and rodents reveals determinants of cross‐species transmission

Abstract

Bats are natural reservoirs of several important emerging viruses. Cross‐species transmission appears to be quite common among bats, which may contribute to their unique reservoir potential. Therefore, understanding the importance of bats as reservoirs requires examining them in a community context rather than concentrating on individual species. Here, we use a network approach to identify ecological and biological correlates of cross‐species virus transmission in bats and rodents, another important host group. We show that given our current knowledge the bat viral sharing network is more connected than the rodent network, suggesting viruses may pass more easily between bat species. We identify host traits associated with important reservoir species: gregarious bats are more likely to share more viruses and bats which migrate regionally are important for spreading viruses through the network. We identify multiple communities of viral sharing within bats and rodents and highlight potential species traits that can help guide studies of novel pathogen emergence.

A Comparative Analysis of Viral Richness and Viral Sharing in Cave-Roosting Bats

“…This disagrees with the one other analysis of roosting behavior and viral richness [14]; however, this study was limited to 52 bat species with roosting behavior information. Our findings support previously published work, indicating that diet was an important life-history trait for viral richness [18,57].…”

“…Our calculated spatial variables rely on an assumption that viral distribution extends across a species' entire geographic range [11,68], although pathogen distribution is likely more constrained to certain bat populations or habitat fragments. Host traits not assessed in this study, but may contribute to viral richness, include level of migration, gregariousness, and cave type [14]. Caves can vary greatly in size and microclimatic profiles, which may influence viral persistence and viral sharing among bat species communities within certain cave environments.…”

“…However, bats have the greatest proportion of zoonotic viruses (i.e., viruses that can infect animals and humans) per species as compared to other mammalian orders [11], potentially due to their unique life-history traits or innate immune system [12,13]. Within the order Chiroptera, several studies have examined the ecological and life-history traits associated with viral richness per species [11,[14][15][16][17][18]. Ecological traits known to increase viral richness in bats include large geographic range size and high number of sympatric species.…”

“…High levels of population genetic structure, large colony size, low conservation threat level, heavier host body mass, and dietary breadth are some of the chiropteran life-history traits that have been associated with high pathogen richness. Luis et al [14] included propensity to roost in caves as an explanatory variable for viral sharing among a subset of 52 bat species, but roosting behavior otherwise has not been explicitly tested as a determinant of viral richness or viral sharing.…”

“…Close contact between conspecific individuals roosting in confined caves could facilitate sustained viral maintenance and potentially greater viral richness, though there are conflicting findings in the literature about the importance of gregariousness in bat-virus dynamics [14,16]. Dense maternity colonies in caves could enhance intraspecific transmission.…”