Anthropogenic roost switching and rabies virus dynamics in house-roosting big brown bats.

Big brown bats (Eptesicus fuscus) are the most commonly encountered rabid bat in North America and represent an important source of wildlife rabies epizootics. Urban and suburban colonies of E. fuscus are often evicted from their roosts in houses, with poorly understood consequences for bat dispersal, population dynamics, and rabies virus transmission. We combined radiotelemetry and mark-recapture of E. fuscus with enhanced surveillance to understand the frequency of rabies virus exposure in house-roosting bats and to assess the potential for behavioral responses of eviction to exacerbate viral transmission. Serology demonstrated the circulation of rabies virus in nearly all sites, with an overall seroprevalence of 12%, but no bats were excreting rabies virus at the time of capture. Bats that were excluded from roosts relocated to houses <1 km from the original roost. However, behavioral responses to eviction differed, with bats switching repeatedly among new roosts in 1 site, but fusing with a neighboring colony in another. These findings confirm the circulation of rabies virus in E. fuscus that live in close contact with humans and companion animals, suggest mechanisms through which anthropogenic disturbance of bats might influence pathogen transmission, and highlight simple strategies to balance conservation and public health priorities.