Lothrop H D, Reisen W K
Arbovirus Research Unit, Center for Vector-Borne Disease Research, School of Veterinary Medicine, University of California, Davis, USA.
J Med Entomol. 2001 Mar;38(2):325-32. doi: 10.1603/0022-2585-38.2.325.
Effective arbovirus transmission requires that the principal vertebrate hosts and vectors have frequent contact. Vegetation and other landscape features used by roosting or nesting birds at night dictate their exposure to nocturnally active host-seeking Culex tarsalis Coquillett and therefore to western equine encephalomyelitis and St. Louis encephalitis viruses. Precipitin tests on 645 Cx. tarsalis that were collected resting and host-seeking near the Salton Sea in Coachella Valley, CA, indicated that passeriform birds (64%) and rabbits (25%) were the most frequent bloodmeal hosts and that the percentage of females feeding on birds varied temporally as an inverse fuction of mosquito abundance. Blood meals were not taken from communally roosting water birds. The spatial distribution of host-seeking females then was investigated by deploying dry ice baited traps within seven sites representative of habitats found along the Salton Sea. Mosquito catch was greatest at traps within elevated vegetation such as Tamarisk, mesquite, cattails, and orchards and lowest at traps positioned at snags over water, sand bars, open fields, and within housing in a small rural community. These data indicate that host-seeking Cx. tarsalis females congregated at specific landscape features that were not necessarily associated with large concentrations of potential bloodmeal hosts.
有效的虫媒病毒传播需要主要脊椎动物宿主和媒介频繁接触。夜间栖息或筑巢鸟类所利用的植被和其他景观特征决定了它们接触夜间活动的寻找宿主的致倦库蚊，进而接触西部马脑炎病毒和圣路易斯脑炎病毒的情况。对在加利福尼亚州科切拉谷索尔顿海附近采集的645只致倦库蚊进行沉淀素试验，结果表明雀形目鸟类（64%）和兔子（25%）是最常见的血餐宿主，且以鸟类为食的雌蚊比例随时间变化，与蚊子数量呈反比。未从群居栖息的水鸟身上获取血餐。然后，通过在代表索尔顿海沿岸栖息地的七个地点部署干冰诱饵诱捕器，研究了寻找宿主的雌蚊的空间分布。在诸如柽柳、豆科灌木、香蒲和果园等高处植被中的诱捕器捕获的蚊子最多，而在水面上的残枝、沙洲、开阔田野以及一个小乡村社区房屋内的诱捕器捕获的蚊子最少。这些数据表明，寻找宿主的致倦库蚊雌蚊聚集在特定的景观特征处，而这些特征不一定与大量潜在血餐宿主的集中分布相关。
