Longitudinal survey of two serotine bat (Eptesicus serotinus) maternity colonies exposed to EBLV-1 (European Bat Lyssavirus type 1): Assessment of survival and serological status variations using capture-recapture models.

Emmanuelle Robardet,Florence Cliquet,Marie Moinet,Evelyne Picard-Meyer,Jacques Barrat,Franck Boué,Alexandre Servat,Olivier Gimenez,Dorothée Jouan,Marine Wasniewski,Elodie Montchâtre-Leroy,Christophe Borel

doi:10.1371/journal.pntd.0006048

Abstract

This study describes two longitudinal serological surveys of European Bat Lyssavirus type 1 (EBLV-1) antibodies in serotine bat (Eptesicus serotinus) maternity colonies located in the North-East of France. This species is currently considered as the main EBLV-1 reservoir. Multievent capture-recapture models were used to determine the factors influencing bat rabies transmission as this method accounts for imperfect detection and uncertainty in disease states. Considering the period of study, analyses revealed that survival and recapture probabilities were not affected by the serological status of individuals, confirming the capacity of bats to be exposed to lyssaviruses without dying. Five bats have been found with EBLV-1 RNA in the saliva at the start of the study, suggesting they were caught during virus excretion period. Among these bats, one was interestingly recaptured one year later and harbored a seropositive status. Along the survey, some others bats have been observed to both seroconvert (i.e. move from a negative to a positive serological status) and serorevert (i.e. move from a positive to a negative serological status). Peak of seroprevalence reached 34% and 70% in site A and B respectively. On one of the 2 sites, global decrease of seroprevalence was observed all along the study period nuanced by oscillation intervals of approximately 2–3 years supporting the oscillation infection dynamics hypothesized during a previous EBLV-1 study in a Myotis myotis colony. Seroprevalence were affected by significantly higher seroprevalence in summer than in spring. The maximum time observed between successive positive serological statuses of a bat demonstrated the potential persistence of neutralizing antibodies for at least 4 years. At last, EBLV-1 serological status transitions have been shown driven by age category with higher seroreversion frequencies in adults than in juvenile. Juveniles and female adults seemed indeed acting as distinct drivers of the rabies virus dynamics, hypothesis have been addressed but their exact role in the EBLV-1 transmission still need to be specified.

Highlights

Chiroptera is the second largest order of mammals after Rodentia
A multi-annual survey of two serotine bat (Eptesicus serotinus) maternity colonies previously found exposed to European Bat Lyssavirus type 1 (EBLV-1) was assessed using capture-recapture methodology
Using capture-recapture models, the authors found that seropositive status of bats did not affect the survival abilities of individuals

Summary

Introduction

Chiroptera is the second largest order of mammals after Rodentia They have a worldwide geographical range, with the exception of Antarctica and are represented by more than 1 100 different species [1], of which 36 are found in Europe. Of these 36, 34 are reported in France, and all of them are strictly protected by national [2, 3] and international [4] legislation as they are sensitive to the destruction of their habitat. The number of recorded species will certainly increase in the future as suggested by the latest isolations of Gannoruwa Bat Lyssavirus in a fruit bat (Pteropus medius) in Sri Lanka, a new candidate in the formal classification of lyssaviruses [21]

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