Latitude and the Duration of Neartic WNV Outbreaks

我们试图探讨的假设，西尼罗河病毒（WNV）的传播力可能更大， 美国北方地区比中纬度地区更严重。为此，我们将确定 库蚊的繁殖季节持续时间，作为主要维持 在这个地区的WNV矢量，与纬度和日长是否限制了持续时间 吸血和随后的生殖活动。首先，我们将定义以下季节动态： 产卵和寄主探索活动的这些蚊子在自然界中。(1.1)产卵活动将是 通过记录从4月到10月沉积在采样装置中的卵筏的丰度进行分析 在美国东海岸沿着34 N至45 N范围的样带的沿着选定地点。(1.2)的 马萨诸塞州波士顿附近吸血活动的季节性将通过在鸟类诱饵中对蚊子进行采样来确定。 猪油罐陷阱C.在这些装置中捕获的尖音蚊将被识别和解剖，以确定 它们是否是经产的，它们的卵巢是否处于滞育状态。我们将（1.3）确定是否 这些C.在卵巢滞育开始后，尖音蚊继续寻找宿主， 把它们收集在定期设置在大型冬眠室的以鸟为诱饵的猪油罐陷阱里， 行为和寿命将被记录。一系列补充实验室观察（1.4）将寻求 确定在不同纬度收集的蚊子后代是否进入和离开卵巢， 滞育反应相似的昼夜或是否蚊子从中纬度滞育在较短的 比那些来自更北的网站。接下来（2），实验室实验将试图确定是否 卵巢的发育和寻找寄主的行为受类似的环境因素的调节。最后 可能性（3）库蚊种群的南北向结构可能比东西向结构更明显 轴将被探索。将对采集的蚊子进行微卫星、RAPD和SSCP标记分析 沿着我们的南北样带以及在800公里空间内取样的其他样带。的存在 将研究近亲繁殖的自体群体。综合起来，这些观察将定义 这些病媒蚊子可能在美国北方扩增西尼罗河病毒的持续时间， 确定该时间段是否与白天长度或环境温度相关。

We seek to explore the hypothesis that the force of transmission of West Nile virus (WNv) may be greater in the northern United States than in more central latitudes. Toward this end, we shall determine whether the duration of the breeding season of Culex p. pipiens, the mosquitoes that serve as the main maintenance vectors of WNv in this region, correlates with latitude and whether day-length limits the duration of blood-feeding and subsequent reproductive activity. First (1), we shall define the seasonal dynamics of oviposition and host-questing activity of these mosquitoes in nature. (1.1) Oviposition activity will be analyzed by recording the abundance of egg-rafts deposited in sampling devices from April through October in selected sites along a transect ranging from 34¿N to 45 ¿ N along the east coast of the US. (1.2) The seasonality of blood-feeding activity near Boston, MA will be defined by sampling mosquitoes in bird-baited lard-can traps. C. pipiens mosquitoes captured in these devices will be identified and dissected to determine whether they are parous and whether their ovaries may be in diapause. We shall (1.3) determine whether these C. pipiens mosquitoes continue to seek hosts after ovarian diapause has commenced by attempting to collect them in bird-baited lard-can traps set periodically in large hibernacula where their reproductive behavior and longevity will be recorded. A series of complementary laboratory observations (1.4) will seek to determine whether the progeny of mosquitoes collected at different latitudes enter and leave ovarian diapause in response to similar diels or whether mosquitoes from the middle latitudes diapause at a shorter diel than those from more northerly sites. Next (2), laboratory experiments will seek to determine whether ovarian development and host-questing behavior are regulated by similar environmental cues. Finally, the possibility (3) that Culex populations may be structured more distinctly on a north-south than an east-west axis will be explored. Microsatellite, RAPD and SSCP markers will be analyzed from mosquitoes sampled along our north-south transect as well as others sampled within an 800 km space. The presence of inbreeding autogenous populations will be investigated. Taken together, these observations will define the duration of the period during which these vector mosquitoes may amplify WNv on the Northern U.S. and will determine whether that period correlates with day length or with ambient temperature.