Patterns of mosquito and arbovirus community composition and ecological indexes of arboviral risk in the northeast United States

BackgroundIn the northeast United States (U.S.), mosquitoes transmit a number of arboviruses, including eastern equine encephalitis, Jamestown Canyon, and West Nile that pose an annual threat to human and animal health. Local transmission of each arbovirus may be driven by the involvement of multiple mosquito species; however, the specificity of these vector-virus associations has not been fully quantified.MethodologyWe used long-term surveillance data consistently collected over 18 years to evaluate mosquito and arbovirus community composition in the State of Connecticut (CT) based on land cover classifications and mosquito species-specific natural histories using community ecology approaches available in the R package VEGAN. We then used binomial-error generalized linear mixed effects models to quantify species-specific trends in arbovirus detections.Primary resultsThe composition of mosquito communities throughout CT varied more among sites than among years, with variation in mosquito community composition among sites explained mostly by a forested-to-developed-land-cover gradient. Arboviral communities varied equally among sites and years, and only developed and forested wetland land cover classifications were associated with the composition of arbovirus detections among sites. Overall, the avian host arboviruses, mainly West Nile and eastern equine encephalitis, displayed the most specific associations among mosquito species and sites, while in contrast, the mammalian host arboviruses (including Cache Valley, Jamestown Canyon, and Potosi) associated with a more diverse mix of mosquito species and were widely distributed throughout CT.ConclusionsWe find that avian arboviruses act as vector specialists infecting a few key mosquito species that associate with discrete habitats, while mammalian arboviruses are largely vector generalists infecting a wide diversity of mosquito species and habitats in the region. These distinctions have important implications for the design and implementation of mosquito and arbovirus surveillance programs as well as mosquito control efforts.研究背景 在美国东北部地区，蚊虫可传播多种虫媒病毒（arbovirus），包括东部马脑炎病毒、詹姆斯敦峡谷病毒以及西尼罗河病毒，上述病毒每年均会对人类与动物健康构成威胁。每种虫媒病毒的本地传播可能由多种蚊虫物种共同参与驱动，但这些媒介生物-病毒关联的特异性尚未得到充分量化。 研究方法 我们采用历时18年的连续监测数据，基于土地覆盖分类以及蚊虫物种特异性自然史特征，借助R语言VEGAN包中的群落生态学分析方法，评估了康涅狄格州（CT）境内蚊虫与虫媒病毒的群落组成。随后我们使用二项分布误差广义线性混合效应模型，量化了不同蚊虫物种在虫媒病毒检测中的趋势特征。 主要研究结果 康涅狄格州全境的蚊虫群落组成在不同采样点间的差异显著大于年度间差异，采样点间蚊虫群落组成的差异主要由森林向开发用地转变的土地覆盖梯度所解释。虫媒病毒群落的差异在采样点间与年度间程度相当，且仅开发用地与森林湿地两类土地覆盖类型与各采样点的虫媒病毒检测组成存在显著关联。总体而言，以鸟类为宿主的虫媒病毒主要包括西尼罗河病毒与东部马脑炎病毒，它们在蚊虫物种与采样点间呈现出最强的特异性关联；与之形成鲜明对比的是，以哺乳动物为宿主的虫媒病毒包括卡奇谷病毒、詹姆斯敦峡谷病毒以及波托西病毒，它们与更多样化的蚊虫类群相关联，且在康涅狄格州境内分布广泛。 研究结论 本研究发现，以鸟类为宿主的虫媒病毒属于媒介专性型病毒，仅能感染少数与特定生境相关联的关键蚊虫物种；而以哺乳动物为宿主的虫媒病毒则大多为媒介泛化型病毒，可感染该区域内多种类群的蚊虫并侵染多样生境。这些差异对于蚊虫与虫媒病毒监测方案的设计与实施，以及蚊虫防控工作均具有重要指导意义。