Abstract

Bats are a diverse and widespread order of mammals. They fulfill critical ecosystem roles but may also act as reservoirs and spreaders for zoonotic agents. Consequently, many recent studies have focused on the potential of bats to spread diseases to other animals and to humans. However, virus transmission networks within bat colonies remain largely unexplored. We studied the detection rate and transmission pathway of astroviruses in a free-ranging Natterer’s bat colony (Myotis nattereri) that exhibits a high fission-fusion dynamic. Based on automatic roost monitoring data of radio-frequency identification tagged bats, we assessed the impact of the strength of an individual’s roosting associations with all other colony members (weighted degree), and the number of roost sites (bat boxes) an individual used—both being proxies for individual exposure risk—on the detected presence of astrovirus-related nucleic acid in individual swab samples. Moreover, we tested to which degree astrovirus sequence types were shared between individuals that frequently roosted together, as proxy for direct transmission risk, and between bats sharing the same roost sites in close temporal succession, as proxy for indirect transmission risk. Neither roosting associations nor the number of different roost sites had an effect on detected virus presence in individual bats. Transmission network data suggest that astroviruses are transmitted both via direct and indirect contact, implying that roost sites pose a risk of astrovirus infection for several days after the bats leave them. Our study offers novel insights in the presence and transmission of viruses within social networks of bat colonies.

Significance statement

Bats provide many ecosystem services but have moved into the focus of virological research as potential carriers of zoonotic disease agents. However, the sparse information available about virus transmission within bat colonies is solely based on simulated transmission data. In this field study, we examined the daily roosting behavior in a wild bat colony in relation to the presence of viruses in individual colony members. Our findings suggest that astroviruses are transmitted by direct contact and via contaminated roost sites. Bats typically defecate in their roost sites, and astroviruses can remain infectious in feces for several days. The here observed virus diversity and roosting behavior suggest that bats can contract astroviruses even if they use contaminated roost sites days after infected individuals have left. This study provides first-time insights in the transmission of astroviruses within bat colonies in the wild.

中文翻译：

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Natterer蝙蝠（Myotis nattereri）的自由裂变融合菌落中星状病毒传播途径的分析

摘要

蝙蝠是哺乳动物的一种广泛多样的物种。它们担当着至关重要的生态系统角色，但也可能充当人畜共患病原体的蓄水池和传播者。因此，最近的许多研究都集中在蝙蝠将疾病传播给其他动物和人类的潜力上。但是，蝙蝠殖民地内的病毒传播网络仍未开发。我们研究了自由放养的Natterer蝙蝠群落（Myotis nattereri）中星状病毒的检出率和传播途径），具有很高的裂变融合动力学。根据带有射频识别标签的蝙蝠的自动栖息监视数据，我们评估了个体与所有其他殖民地成员的栖息联系强度（加权度）以及个人使用的栖息地数量（蝙蝠箱）的影响，两者都是个人暴露风险的代表-检测到在单个拭子样品中存在与星状病毒相关的核酸。此外，我们测试了经常栖息在一起的个体之间星状病毒序列类型在多大程度上被共享，以作为直接传播风险的代理，在蝙蝠之间以紧密的时间连续性共享相同栖息地的蝙蝠之间，被作为间接传播风险的代理。栖息地协会或不同栖息地的数量都不会影响单个蝙蝠中检测到的病毒的存在。传输网络的数据表明，星状病毒是通过直接和间接接触传播的，这意味着在蝙蝠离开它们后的几天里，栖息地会带来感染星状病毒的风险。我们的研究为蝙蝠群体的社交网络中病毒的存在和传播提供了新颖的见解。

重要性声明

蝙蝠提供许多生态系统服务，但已成为人畜共患病病原体的潜在载体而成为病毒学研究的重点。但是，关于蝙蝠菌落内病毒传播的可用稀疏信息仅基于模拟传播数据。在这项现场研究中，我们检查了与单个殖民地成员中病毒的存在有关的野生蝙蝠殖民地的日常栖息行为。我们的发现表明，星状病毒是通过直接接触并通过受污染的栖息地传播的。蝙蝠通常在其栖息地排便，而星状病毒可在粪便中保持传染性达数天之久。此处观察到的病毒多样性和栖息行为表明，即使蝙蝠在感染的个体离开后数天使用受污染的栖息地，它们也可以感染星状病毒。