Abstract：
UNASSIGNED: West Nile Virus (WNV) is a zoonotic arbovirus worldwide spread. Seasonal WNV outbreaks occur in the Mediterranean basin since the late 1990\'s with ever-increasing incidence. In Southern Spain WNV is endemic, as disease foci - caused by WNV lineage 1 (WNV-L1) strains - occur every year. On the contrary, WNV-L2 is the dominant lineage in Europe, so most European WNV sequences available belong to this lineage, WNV-L1 sequences being still scarce.
UNASSIGNED: To fill this gap, this study reports the genetic characterisation of 27 newly described WNV-L1 strains, involved in outbreaks affecting wild birds and horses during the last decade in South-Western Spain.
UNASSIGNED: All strains except one belong to the Western Mediterranean-1 sub-cluster (WMed-1), related phylogenetically to Italian, French, Portuguese, Moroccan and, remarkably, Senegalese strains. This sub-cluster persisted, spread and evolved into three distinguishable WMed-1 phylogenetic groups that co-circulated, notably, in the same province (Cádiz). They displayed different behaviours: from long-term persistence and rapid spread to neighbouring regions within Spain, to long-distance spread to different countries, including transcontinental spread to Africa. Among the different introductions of WNV in Spain revealed in this study, some of them succeeded to get established, some extinguished from the territory shortly afterwards. Furthermore, Spain\'s southernmost province, Cádiz, constitutes a hotspot for virus incursion.
UNASSIGNED: Southern Spain seems a likely scenario for emergence of exotic pathogens of African origin. Therefore, circulation of diverse WNV-L1 variants in Spain prompts for an extensive surveillance under a One Health approach.
UNASSIGNED: To fill this gap, this study reports the genetic characterisation of 27 newly described WNV-L1 strains, involved in outbreaks affecting wild birds and horses during the last decade in South-Western Spain.
UNASSIGNED: All strains except one belong to the Western Mediterranean-1 sub-cluster (WMed-1), related phylogenetically to Italian, French, Portuguese, Moroccan and, remarkably, Senegalese strains. This sub-cluster persisted, spread and evolved into three distinguishable WMed-1 phylogenetic groups that co-circulated, notably, in the same province (Cádiz). They displayed different behaviours: from long-term persistence and rapid spread to neighbouring regions within Spain, to long-distance spread to different countries, including transcontinental spread to Africa. Among the different introductions of WNV in Spain revealed in this study, some of them succeeded to get established, some extinguished from the territory shortly afterwards. Furthermore, Spain\'s southernmost province, Cádiz, constitutes a hotspot for virus incursion.
UNASSIGNED: Southern Spain seems a likely scenario for emergence of exotic pathogens of African origin. Therefore, circulation of diverse WNV-L1 variants in Spain prompts for an extensive surveillance under a One Health approach.
摘要：
■西尼罗河病毒（WNV）是一种世界范围内传播的人畜共患虫媒病毒。自1990年代后期以来，地中海盆地发生季节性WNV暴发，发病率不断增加。在西班牙南部，WNV是地方病，作为由WNV谱系1（WNV-L1）菌株引起的疾病病灶，每年都会发生。相反,WNV-L2是欧洲的主要血统，所以大多数欧洲WNV序列都属于这个谱系，WNV-L1序列仍然稀缺。
■为了填补这一空白，这项研究报告了27个新描述的WNV-L1菌株的遗传特征，在过去的十年里，西班牙西南部的野鸟和马都受到了疫情的影响。
■除一个菌株外，所有菌株都属于西地中海1子群（WMed-1），在系统发育上与意大利语相关，法语,葡萄牙语,摩洛哥和,值得注意的是，塞内加尔菌株。此子集群持续存在，传播并进化成三个可区分的WMed-1系统发育群体，特别是,在同一省（加的斯）。他们表现出不同的行为：从长期坚持和迅速传播到西班牙的邻近地区，远距离传播到不同的国家，包括跨大陆传播到非洲。在这项研究中揭示的西班牙WNV的不同介绍中，他们中的一些人成功地建立了，一些人不久后从领土上熄灭。此外，西班牙最南端的省份,卡迪兹,构成了病毒入侵的热点。
■西班牙南部似乎是非洲起源的外来病原体出现的可能情况。因此,不同的WNV-L1变种在西班牙的流通促使在“一个健康”方法下进行广泛的监测。
■为了填补这一空白，这项研究报告了27个新描述的WNV-L1菌株的遗传特征，在过去的十年里，西班牙西南部的野鸟和马都受到了疫情的影响。
■除一个菌株外，所有菌株都属于西地中海1子群（WMed-1），在系统发育上与意大利语相关，法语,葡萄牙语,摩洛哥和,值得注意的是，塞内加尔菌株。此子集群持续存在，传播并进化成三个可区分的WMed-1系统发育群体，特别是,在同一省（加的斯）。他们表现出不同的行为：从长期坚持和迅速传播到西班牙的邻近地区，远距离传播到不同的国家，包括跨大陆传播到非洲。在这项研究中揭示的西班牙WNV的不同介绍中，他们中的一些人成功地建立了，一些人不久后从领土上熄灭。此外，西班牙最南端的省份,卡迪兹,构成了病毒入侵的热点。
■西班牙南部似乎是非洲起源的外来病原体出现的可能情况。因此,不同的WNV-L1变种在西班牙的流通促使在“一个健康”方法下进行广泛的监测。
