Martin Gerardo, Yanez-Arenas Carlos, Plowright Raina K, Chen Carla, Roberts Billie, Skerratt Lee F
One Health Research Group, College of Public Health, Medical and Veterinary Sciences, James Cook University, Townsville, QLD, Australia.
Laboratorio de Conservación de la Biodiversidad, Parque Científico y Tecnológico de Yucatán, Universidad, Universidad Nacional Autónoma de México, Mérida, Yucatán, Mexico.
Ecohealth. 2018 Sep;15(3):526-542. doi: 10.1007/s10393-017-1309-y. Epub 2018 Jan 18.
Understanding environmental factors driving spatiotemporal patterns of disease can improve risk mitigation strategies. Hendra virus (HeV), discovered in Australia in 1994, spills over from bats (Pteropus sp.) to horses and thence to humans. Below latitude - 22°, almost all spillover events to horses occur during winter, and above this latitude spillover is aseasonal. We generated a statistical model of environmental drivers of HeV spillover per month. The model reproduced the spatiotemporal pattern of spillover risk between 1994 and 2015. The model was generated with an ensemble of methods for presence-absence data (boosted regression trees, random forests and logistic regression). Presences were the locations of horse cases, and absences per spatial unit (2.7 × 2.7 km pixels without spillover) were sampled with the horse census of Queensland and New South Wales. The most influential factors indicate that spillover is associated with both cold-dry and wet conditions. Bimodal responses to several variables suggest spillover involves two systems: one above and one below a latitudinal area close to - 22°. Northern spillovers are associated with cold-dry and wet conditions, and southern with cold-dry conditions. Biologically, these patterns could be driven by immune or behavioural changes in response to food shortage in bats and horse husbandry. Future research should look for differences in these traits between seasons in the two latitudinal regions. Based on the predicted risk patterns by latitude, we recommend enhanced preventive management for horses from March to November below latitude 22° south.
了解驱动疾病时空模式的环境因素有助于改进风险缓解策略。亨德拉病毒（HeV）于1994年在澳大利亚被发现，它从蝙蝠（狐蝠属）传播到马，进而传播到人类。在南纬22°以南，几乎所有马的病毒外溢事件都发生在冬季，而在该纬度以北，病毒外溢没有季节性。我们建立了一个每月HeV外溢环境驱动因素的统计模型。该模型再现了1994年至2015年间病毒外溢风险的时空模式。该模型是用一系列处理存在-缺失数据的方法（增强回归树、随机森林和逻辑回归）生成的。存在数据是马感染病例的位置，每个空间单元（2.7×2.7千米无病毒外溢的像素区域）的缺失数据是通过昆士兰和新南威尔士的马匹普查进行采样的。最具影响力的因素表明，病毒外溢与寒冷干燥和潮湿的条件都有关。对几个变量的双峰反应表明，病毒外溢涉及两个系统：一个在南纬接近22°的纬度区域之上，另一个在该区域之下。北部的病毒外溢与寒冷干燥和潮湿条件有关，而南部的病毒外溢与寒冷干燥条件有关。从生物学角度来看，这些模式可能是由蝙蝠和马匹饲养中食物短缺导致的免疫或行为变化所驱动的。未来的研究应该寻找这两个纬度区域不同季节这些特征的差异。根据预测的按纬度划分的风险模式，我们建议在南纬22°以南地区，从3月到11月加强对马匹的预防性管理。
