Latitude and the Duration of Neartic WNV Outbreaks

超出所提供的空间。我们试图探索一种假设，即西尼罗河病毒（WNv）在美国北部的传播力可能比在更多的中纬度地区更大。为此，我们将确定该地区作为西尼罗河病毒主要维持媒介的库蚊孳生季节的持续时间是否与纬度相关，以及日长是否限制了吸血和随后的繁殖活动的持续时间。首先(1)明确了这些蚊子在自然界中产卵和寻宿主活动的季节动态。（1.1）产卵活动将通过记录4月至10月在美国东海岸沿34°N至45°N的样带选定地点的取样装置中沉积的卵筏的丰度来分析。（1.2）马萨诸塞州波士顿附近吸血活动的季节性将通过在鸟饵猪油罐陷阱中取样蚊子来确定。在这些装置中捕获的库蚊将被鉴定和解剖，以确定它们是否已经分娩，以及它们的卵巢是否处于滞育状态。我们将（1.3）确定这些库蚊在卵巢滞育开始后是否继续寻找宿主，方法是将它们收集在大型冬眠地定期设置的以鸟为诱饵的猪油罐陷阱中，并记录它们的繁殖行为和寿命。一系列补充性的实验室观察（1.4）将试图确定在不同纬度收集的蚊子的后代是否会根据相似的昼夜节律进入和离开卵巢滞育，或者来自中纬度地区的蚊子是否会比来自更北纬地区的蚊子在更短的昼夜节律中滞育。接下来，实验室实验将试图确定卵巢发育和寻找宿主行为是否受到类似环境线索的调节。最后，将探讨库蚊种群在南北轴上比在东西轴上结构更明显的可能性。将分析沿我们的南北样带以及800公里范围内采样的其他蚊子的微卫星、RAPD和SSCP标记。将调查近交自交群体的存在。总之，这些观察结果将确定这些媒介蚊子可能在美国北部扩增西尼罗河病毒的时间段，并将确定该时间段是否与白昼长度或环境温度相关。网站性能 ======================================== 节结束 ===========================================

EXCEED THE SPACE PROVIDED. 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. PERFORMANCE SITE ========================================Section End===========================================