title: Flying-fox roost disturbance and Hendra virus spillover risk.
abstract: Bats of the genus Pteropus (flying-foxes) are the natural host of Hendra virus (HeV) which periodically causes fatal disease in horses and humans in Australia. The increased urban presence of flying-foxes often provokes negative community sentiments because of reduced social amenity and concerns of HeV exposure risk, and has resulted in calls for the dispersal of urban flying-fox roosts. However, it has been hypothesised that disturbance of urban roosts may result in a stress-mediated increase in HeV infection in flying-foxes, and an increased spillover risk. We sought to examine the impact of roost modification and dispersal on HeV infection dynamics and cortisol concentration dynamics in flying-foxes. The data were analysed in generalised linear mixed models using restricted maximum likelihood (REML). The difference in mean HeV prevalence in samples collected before (4.9%), during (4.7%) and after (3.4%) roost disturbance was small and non-significant (P = 0.440). Similarly, the difference in mean urine specific gravity-corrected urinary cortisol concentrations was small and non-significant (before = 22.71 ng/mL, during = 27.17, after = 18.39) (P= 0.550). We did find an underlying association between cortisol concentration and season, and cortisol concentration and region, suggesting that other (plausibly biological or environmental) variables play a role in cortisol concentration dynamics. The effect of roost disturbance on cortisol concentration approached statistical significance for region, suggesting that the relationship is not fixed, and plausibly reflecting the nature and timing of disturbance. We also found a small positive statistical association between HeV excretion status and urinary cortisol concentration. Finally, we found that the level of flying-fox distress associated with roost disturbance reflected the nature and timing of the activity, highlighting the need for a 'best practice' approach to dispersal or roost modification activities. The findings usefully inform public discussion and policy development in relation to Hendra virus and flying-fox management.
authors.affiliation: Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia.
authors.forename: Daniel
authors.initials: D
authors.lastname: Edson
authors.affiliation: Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia; EcoHealth Alliance, New York, New York, United States of America.
authors.forename: Hume
authors.initials: H
authors.lastname: Field
authors.affiliation: Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia; School of Veterinary Science, The University of Queensland, Gatton, Queensland, Australia.
authors.forename: Lee
authors.initials: L
authors.lastname: McMichael
authors.affiliation: Department of Primary Industries, Wollongbar, New South Wales, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Jordan
authors.affiliation: Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia.
authors.forename: Nina
authors.initials: N
authors.lastname: Kung
authors.affiliation: Department of Agriculture and Fisheries, Brisbane, Queensland, Australia.
authors.forename: David
authors.initials: D
authors.lastname: Mayer
authors.affiliation: Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia.
authors.forename: Craig
authors.initials: C
authors.lastname: Smith
mesh_terms: D000818:Animals; D001315:Australia; D002685:Chiroptera / Q000652:urine* / Q000821:virology*; D045404:Hendra Virus / Q000302:isolation & purification*; D045464:Henipavirus Infections / Q000453:epidemiology; D006854:Hydrocortisone / Q000652:urine; D012621:Seasons
chemical_list: D006854:Hydrocortisone