Roost selection by synanthropic bats in rural Kenya: implications for human–wildlife conflict and zoonotic pathogen spillover

Abstract

Many wildlife species are synanthropic and use structures built by humans, creating a high-risk interface for human–wildlife conflict and zoonotic pathogen spillover. However, studies that investigate features of urbanizing areas that attract or repel wildlife are currently lacking. We surveyed 85 buildings used by bats and 172 neighbouring buildings unused by bats (controls) in southeastern Kenya during 2021 and 2022 and evaluated the role of microclimate and structural attributes in building selection. We identified eight bat species using buildings, with over 25% of building roosts used concurrently by multiple species. Bats selected taller cement-walled buildings with higher water vapour pressure and lower presence of permanent human occupants. However, roost selection criteria differed across the most common bat species: molossids selected structures like those identified by our main dataset whereas Cardioderma cor selected buildings with lower presence of permanent human occupants. Our results show that roost selection of synanthropic bat species is based on specific buildings attributes. Further, selection criteria that facilitate bat use of buildings are not homogeneous across species. These results provide information on the general mechanisms of bat–human contact in rural settings, as well as specific information on roost selection for synanthropic bats in urbanizing Africa.

Frequent and intense human-bat interactions occur in buildings of rural Kenya

“…Predation and consumption of bats can facilitate transmission of zoonotic pathogens into consumers, including domestic animals [41], which can also serve as bridge or intermediate hosts for onward transmission to humans [42]. Furthermore, bats often roost in livestock enclosures in this region and may deposit feces or bodily fluids in spaces frequently used by domestic animals [43]. Many frugivorous bat species chew and eject salivacovered fruit pulp below their roosts, which domestic animals may then consume and become exposed to shed pathogens [44].…”

“…Across Africa, bats are frequently found in anthropogenic structures where there is increased likelihood of human exposure to bats and, consequently, their pathogens [28][29][30][31]. Measures mitigating human-bat contact in such settings, such as structural modifications to existing structures that reduce the likelihood of bat use, the construction of buildings inaccessible to bats, or campaigns educating the public about the importance of (and public health concerns associated with) bats, may be instrumental in reducing risk for human exposure to bat-borne pathogens [29,43,51]. Previous work in Taita-Taveta county suggests that modification of building microclimate and proper sealing of buildings, especially in modern tall, cement-walled structures, may reduce bat presence [32,43].…”

“…Measures mitigating human-bat contact in such settings, such as structural modifications to existing structures that reduce the likelihood of bat use, the construction of buildings inaccessible to bats, or campaigns educating the public about the importance of (and public health concerns associated with) bats, may be instrumental in reducing risk for human exposure to bat-borne pathogens [29,43,51]. Previous work in Taita-Taveta county suggests that modification of building microclimate and proper sealing of buildings, especially in modern tall, cement-walled structures, may reduce bat presence [32,43]. Continent-wide efforts to similarly adjust housing attributes based on local bat selection parameters may be beneficial to reducing bat occupancy in buildings.…”

Anthropogenic structures promote frequent and intense contact between humans and bats in rural Kenya

“…Predation and consumption of bats can facilitate transmission of zoonotic parasites into consumers, including domestic animals (Karesh and Noble 2009), which can also serve as bridge hosts for onward transmission to humans (Salinas-Ramos et al 2021). Furthermore, bats will roost in livestock enclosures in this region and may deposit feces or bodily fluids in spaces frequently used by domestic animals (Jackson et al 2023). Many frugivorous bat species may chew and eject saliva-covered fruit pulp below their roosts, which domestic animals may also then consume and become exposed to shed pathogens (Openshaw et al 2016).…”