Arnal Audrey, Gómez-Díaz Elena, Cerdà-Cuéllar Marta, Lecollinet Sylvie, Pearce-Duvet Jessica, Busquets Núria, García-Bocanegra Ignacio, Pagès Nonito, Vittecoq Marion, Hammouda Abdessalem, Samraoui Boudjéma, Garnier Romain, Ramos Raül, Selmi Slaheddine, González-Solís Jacob, Jourdain Elsa, Boulinier Thierry
Centre d'Ecologie Fonctionnelle et Evolutive, UMR 5175, CNRS, Montpellier, France; Centre de recherche de la Tour du Valat, Arles, France.
Institut de Biologia Evolutiva CSIC-Universitat Pompeu Fabra, Barcelona, Spain.
PLoS One. 2014 Mar 13;9(3):e89601. doi: 10.1371/journal.pone.0089601. eCollection 2014.
In recent years, a number of zoonotic flaviviruses have emerged worldwide, and wild birds serve as their major reservoirs. Epidemiological surveys of bird populations at various geographical scales can clarify key aspects of the eco-epidemiology of these viruses. In this study, we aimed at exploring the presence of flaviviruses in the western Mediterranean by sampling breeding populations of the yellow-legged gull (Larus michahellis), a widely distributed, anthropophilic, and abundant seabird species. For 3 years, we sampled eggs from 19 breeding colonies in Spain, France, Algeria, and Tunisia. First, ELISAs were used to determine if the eggs contained antibodies against flaviviruses. Second, neutralization assays were used to identify the specific flaviviruses present. Finally, for colonies in which ELISA-positive eggs had been found, chick serum samples and potential vectors, culicid mosquitoes and soft ticks (Ornithodoros maritimus), were collected and analyzed using serology and PCR, respectively. The prevalence of flavivirus-specific antibodies in eggs was highly spatially heterogeneous. In northeastern Spain, on the Medes Islands and in the nearby village of L'Escala, 56% of eggs had antibodies against the flavivirus envelope protein, but were negative for neutralizing antibodies against three common flaviviruses: West Nile, Usutu, and tick-borne encephalitis viruses. Furthermore, little evidence of past flavivirus exposure was obtained for the other colonies. A subset of the Ornithodoros ticks from Medes screened for flaviviral RNA tested positive for a virus whose NS5 gene was 95% similar to that of Meaban virus, a flavivirus previously isolated from ticks of Larus argentatus in western France. All ELISA-positive samples subsequently tested positive for Meaban virus neutralizing antibodies. This study shows that gulls in the western Mediterranean Basin are exposed to a tick-borne Meaban-like virus, which underscores the need of exploring the spatial and temporal distribution of this flavivirus as well as its potential pathogenicity for animals and humans.
近年来，多种人畜共患黄病毒在全球范围内出现，野生鸟类是其主要宿主。在不同地理尺度上对鸟类种群进行流行病学调查，可以阐明这些病毒生态流行病学的关键方面。在本研究中，我们旨在通过对黄腿鸥（Larus michahellis）的繁殖种群进行采样，探索西地中海地区黄病毒的存在情况。黄腿鸥是一种分布广泛、亲近人类且数量众多的海鸟。连续3年，我们从西班牙、法国、阿尔及利亚和突尼斯的19个繁殖群体中采集鸟蛋。首先，使用酶联免疫吸附测定（ELISA）来确定鸟蛋中是否含有抗黄病毒的抗体。其次，采用中和试验来鉴定存在的特定黄病毒。最后，对于发现ELISA阳性鸟蛋的群体，分别采集雏鸡血清样本以及潜在的传播媒介——库蚊和软蜱（滨海钝缘蜱，Ornithodoros maritimus），并分别通过血清学和聚合酶链反应（PCR）进行分析。鸟蛋中黄病毒特异性抗体的流行率在空间上具有高度异质性。在西班牙东北部的梅德斯群岛以及附近的埃斯卡拉村，56%的鸟蛋含有抗黄病毒包膜蛋白的抗体，但针对三种常见黄病毒（西尼罗河病毒、乌苏图病毒和蜱传脑炎病毒）的中和抗体检测呈阴性。此外，在其他群体中几乎没有获得过去接触黄病毒的证据。对来自梅德斯群岛的滨海钝缘蜱样本进行黄病毒RNA筛查，其中一部分样本检测出一种病毒呈阳性，其非结构蛋白5（NS5）基因与梅阿班病毒的NS5基因相似度为95%。梅阿班病毒是一种先前从法国西部银鸥蜱中分离出的黄病毒。所有ELISA阳性样本随后检测出梅阿班病毒中和抗体呈阳性。本研究表明，西地中海盆地的海鸥接触到一种蜱传的类梅阿班病毒，这凸显了探索这种黄病毒的时空分布及其对动物和人类潜在致病性的必要性。
