Departamento de Sanidad Animal, Facultad de Veterinaria, Universidad de Córdoba, Córdoba, Spain.
Center for Animal Disease Modeling and Surveillance (CADMS), Department of Medicine & Epidemiology, School of Veterinary Medicine, University of California, Davis, CA, USA.
Transbound Emerg Dis. 2018 Apr;65(2):567-577. doi: 10.1111/tbed.12742. Epub 2017 Oct 16.
During the last decade, West Nile virus (WNV) outbreaks have increased sharply in both horses and human in Europe. The aims of this study were to evaluate characteristics and spatio-temporal distribution of WNV outbreaks in horses in Spain between 2010 and 2016 in order to identify the environmental variables most associated with WNV occurrence and to generate high-resolution WNV suitability maps to inform risk-based surveillance strategies in this country. Between August 2010 and November 2016, a total of 403 WNV suspected cases were investigated, of which, 177 (43.9%) were laboratory confirmed. Mean values of morbidity, mortality and case fatality rates were 7.5%, 1.6% and 21.2%, respectively. The most common clinical symptoms were as follows: tiredness/apathy, recumbency, muscular tremor, ataxia, incoordination and hyperaesthesia. The outbreaks confirmed during the last 7 years, with detection of WNV RNA lineage 1 in 2010, 2012, 2013, 2015 and 2016, suggest an endemic circulation of the virus in Spain. The spatio-temporal distribution of WNV outbreaks in Spain was not homogeneous, as most of them (92.7%) were concentrated in western part of Andalusia (southern Spain) and significant clusters were detected in this region in two non-consecutive years. These findings were supported by the results of the space-time scan statistics permutation model. A presence-only MaxEnt ecological niche model was used to generate a suitability map for WNV occurrence in Andalusia. The most important predictors selected by the Ecological Niche Modeling were as follows: mean annual temperature (49.5% contribution), presence of Culex pipiens (19.5% contribution), mean annual precipitation (16.1% contribution) and distance to Ramsar wetlands (14.9% contribution). Our results constitute an important step for understanding WNV emergence and spread in Spain and will provide valuable information for the development of more cost-effective surveillance and control programmes and improve the protection of horse and human populations in WNV-endemic areas.
在过去的十年中，西尼罗河病毒（WNV）在欧洲的马和人类中爆发的频率急剧增加。本研究的目的是评估 2010 年至 2016 年间西班牙马中 WNV 爆发的特征和时空分布，以确定与 WNV 发生最相关的环境变量，并生成高分辨率的 WNV 适宜性地图，为该国的基于风险的监测策略提供信息。2010 年 8 月至 2016 年 11 月期间，共调查了 403 例疑似 WNV 病例，其中 177 例（43.9%）经实验室确诊。发病率、死亡率和病死率的平均值分别为 7.5%、1.6%和 21.2%。最常见的临床症状如下：疲倦/冷漠、卧地不起、肌肉震颤、共济失调、不协调和感觉过敏。过去 7 年中确认的暴发，以及 2010 年、2012 年、2013 年、2015 年和 2016 年检测到的 WNV RNA 谱系 1，表明该病毒在西班牙的流行循环。西班牙的 WNV 暴发的时空分布并不均匀，因为其中大部分（92.7%）集中在安达卢西亚西部（西班牙南部），在这一地区的两个非连续年份中检测到了显著的集群。这些发现得到了时空扫描统计置换模型结果的支持。采用存在-only MaxEnt 生态位模型生成安达卢西亚 WNV 发生的适宜性地图。生态位模型选择的最重要预测因子如下：年均温度（49.5%的贡献）、库蚊存在（19.5%的贡献）、年均降水量（16.1%的贡献）和距拉姆萨尔湿地的距离（14.9%的贡献）。我们的研究结果为了解 WNV 在西班牙的出现和传播提供了重要的一步，将为制定更具成本效益的监测和控制计划提供有价值的信息，并提高 WNV 流行地区马和人类的保护水平。
