Edson Daniel, Field Hume, McMichael Lee, Jordan David, Kung Nina, Mayer David, Smith Craig
Queensland Centre for Emerging Infectious Diseases, Biosecurity Queensland, Department of Agriculture and Fisheries, Brisbane, Queensland, Australia.
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.
PLoS One. 2015 May 27;10(5):e0125881. doi: 10.1371/journal.pone.0125881. eCollection 2015.
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.
狐蝠属（飞狐）蝙蝠是亨德拉病毒（HeV）的天然宿主，该病毒在澳大利亚会定期导致马匹和人类患上致命疾病。飞狐在城市中出现的频率增加，常常引发社区的负面情绪，原因是社会便利设施减少以及对感染亨德拉病毒风险的担忧，这导致人们呼吁驱散城市中的飞狐栖息地。然而，有假设认为，干扰城市栖息地可能会导致压力介导的飞狐体内亨德拉病毒感染增加，以及溢出风险上升。我们试图研究栖息地改造和驱散对飞狐体内亨德拉病毒感染动态和皮质醇浓度动态的影响。使用限制最大似然法（REML）在广义线性混合模型中对数据进行分析。在栖息地受到干扰之前（4.9%）、期间（4.7%）和之后（3.4%）采集的样本中，亨德拉病毒平均流行率的差异很小且无统计学意义（P = 0.440）。同样，平均尿比重校正后的尿皮质醇浓度差异也很小且无统计学意义（之前 = 22.71 ng/mL，期间 = 27.17，之后 = 18.39）（P = 0.550）。我们确实发现皮质醇浓度与季节以及皮质醇浓度与地区之间存在潜在关联，这表明其他（可能是生物学或环境方面的）变量在皮质醇浓度动态中起作用。栖息地干扰对皮质醇浓度的影响在地区方面接近统计学意义，这表明这种关系并非固定不变，可能反映了干扰的性质和时间。我们还发现亨德拉病毒排泄状态与尿皮质醇浓度之间存在微小但具有统计学意义的正相关。最后，我们发现与栖息地干扰相关的飞狐痛苦程度反映了活动的性质和时间，这凸显了在驱散或栖息地改造活动中采用“最佳实践”方法的必要性。这些发现为有关亨德拉病毒和飞狐管理的公众讨论和政策制定提供了有益信息。
