Mating behaviour and connectivity drive sporadic European bat lyssavirus 2 infections in Myotis myotis

Abstract

Understanding the transmission and persistence of zoonoses in wild reservoirs is crucial for outbreak prevention, demographic assessment, and conservation planning. Host demography, ecology, behaviour and within-host viral kinetics together underpin transmission dynamics but are rarely united within epidemiological models. Here we characterised the transmission dynamics of European bat lyssavirus 2 (EBLV-2) infection dynamics by uniting a long-term study (2010-2018) of the ecology of five greater mouse-eared bat (Myotis myotis) colonies in France (~2700 marked individuals) with diagnostic evidence of virus circulation. Although no lyssavirus was detected in any of the 442 saliva samples tested, seropositivity showed synchronised peaks across colonies (0-100% annually), with the highest seroprevalence in 2015-2017, but remaining low otherwise. Fitting Bayesian compartmental epidemiological models, we found evidence that shifts in EBLV-2 prevalence were primarily driven by the gregarious behaviour of populations during the mating season and age-dependent variation in transmission. The duration of maternal immunity emerged as a key, and still empirically unknown factor, which shaped whether EBLV-2 maintenance was enzootic or required an external force of infection. Lyssavirus outbreaks in M. myotis were associated with few deaths overall and had a negligible impact on population dynamics. These findings underscore the value of integrating ecological and individual-level data with mechanistic modelling to enhance our understanding and management of zoonotic pathogens in wildlife.