Rodríguez-Valencia Víctor, Olive Marie-Marie, Le Goff Gilbert, Faisse Marine, Bourel Marie, L'Ambert Grégory, Vollot Benjamin, Tolsá-García María José, Paupy Christophe, Roiz David
MIVEGEC, Univ. Montpellier, IRD, CNRS, Montpellier, France.
International Joint Laboratory ELDORADO, IRD/UNAM, Mexico City, Mexico.
Med Vet Entomol. 2025 Mar 21. doi: 10.1111/mve.12802.
The spread of the West Nile (WNV) and Usutu (USUV) flaviviruses in Europe in recent decades highlights the urgent need to understand the transmission networks of these pathogens as a basis for effective decision-making. These viruses are part of a complex disease cycle that involves birds as principal hosts and humans and horses as dead-end hosts. Our study aims to uncover the intricate relationships between the main mosquito vector of these viruses, Culex pipiens L. (Diptera: Culicidae) and its feeding preferences based on the forage ratio among several host species, primarily birds in a land-use gradient. We estimated the bird host potential to act as a host for flavivirus, the reservoir capacity index, based on forage ratios and potential host competence based on molecular prevalence. We sampled mosquitoes and, at the same time, conducted bird censuses in the Camargue region in southern France, where co-circulation of these viruses has been reported. Several localities were sampled along a land-use gradient in peri-urban, agricultural and natural areas from May to November 2021. We identified 55 vertebrate species in 110 engorged Cx. pipiens by PCR amplification and sequencing of mitochondrial 12S and 16S Ribosomal DNA genes. Culex pipiens feeds primarily on 51 bird species and secondarily on two mammals, one amphibian and one reptile. Based on forage ratios, we found a preference of Cx. pipiens in the Camargue for the order Passeriformes and, more specifically, for Columba livia domestica L. (Columbiformes: Columbidae) in agricultural areas, and for Passer domesticus/montanus L. (Passeriformes: Passeridae), in agricultural and peri-urban areas. The natural habitats had significantly higher forage ratio values than agricultural and peri-urban areas. We suggest that certain key species, such as Passer sp., Columba livia and Turdus sp., might be potentially considered locally relevant hosts for transmission in this area, as they are important for mosquito feeding and also potentially important hosts for flavivirus amplification. These data will be beneficial in understanding host-vector interactions and the relationships between bird communities, mosquito feeding preferences and emerging mosquito-borne diseases.
近几十年来，西尼罗河病毒（WNV）和乌苏图病毒（USUV）在欧洲的传播凸显了迫切需要了解这些病原体的传播网络，以此作为有效决策的基础。这些病毒是复杂疾病循环的一部分，该循环以鸟类作为主要宿主，而人类和马匹作为终末宿主。我们的研究旨在揭示这些病毒的主要蚊媒——致倦库蚊（双翅目：蚊科）与其摄食偏好之间的复杂关系，摄食偏好基于几种宿主物种之间的觅食比例，主要是在土地利用梯度中的鸟类。我们根据觅食比例估计了鸟类宿主作为黄病毒宿主的潜力，即储存能力指数，并根据分子流行率估计了潜在宿主能力。我们在法国南部的卡马尔格地区对蚊子进行采样，同时开展鸟类普查，该地区已报告这些病毒共同传播。2021年5月至11月，我们沿着城市周边、农业和自然区域的土地利用梯度对几个地点进行了采样。通过对线粒体12S和16S核糖体DNA基因进行PCR扩增和测序，我们在110只饱腹的致倦库蚊中鉴定出55种脊椎动物物种。致倦库蚊主要吸食51种鸟类的血液，其次吸食两种哺乳动物、一种两栖动物和一种爬行动物的血液。基于觅食比例，我们发现卡马尔格地区的致倦库蚊偏好雀形目，更具体地说，在农业地区偏好家鸽（鸽形目：鸠鸽科），在农业和城市周边地区偏好家麻雀/山麻雀（雀形目：麻雀科）。自然栖息地的觅食比例值显著高于农业和城市周边地区。我们建议，某些关键物种，如麻雀属、家鸽和鸫属，可能在当地被视为该地区病毒传播的相关宿主，因为它们对蚊子摄食很重要，并且也可能是黄病毒扩增的重要宿主。这些数据将有助于理解宿主-媒介相互作用以及鸟类群落、蚊子摄食偏好和新出现的蚊媒疾病之间的关系。
