Latitude and the Duration of Neartic WNV Outbreaks

近地西尼罗河病毒爆发的纬度和持续时间

• 批准号: 6617435
• 负责人: Andrew Spielman
• 金额: $ 13.62万
• 依托单位: HARVARD SCHOOL OF PUBLIC HEALTH
• 依托单位国家: 美国
• 财政年份: 2003
• 资助国家: 美国
• 起止时间: 2003-09-30 至 2008-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6617435
• 关键词: Culicidae; United States; West Nile virus; arthropod borne communicable disease; bioperiodicity; charge coupled device camera; disease outbreaks; disease vectors; emerging infectious disease; hibernation; insect control; life cycle; ovary; polymerase chain reaction; reproduction; sex behavior; temperature

DESCRIPTION (provided by the applicant): 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 degrees N to 45 degrees 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.

描述(由申请人提供)：我们试图探索这样一种假设，即西尼罗河病毒(WNV)在美国北部的传播力可能比在更中部的纬度更大。为此，我们将确定作为该地区西尼罗河病毒主要维持媒介的淡库蚊繁殖季节的持续时间是否与纬度有关，以及日长是否限制了觅血和随后的生殖活动的持续时间。首先，我们将定义自然界中这些蚊子的产卵和寄主活动的季节动态。(1.1)产卵活动将通过记录4月至10月期间在美国东海岸北纬34度至45度的样带上选定的地点放置在采样设备中的卵排的丰度来分析。(1.2)马萨诸塞州波士顿附近觅血活动的季节性将通过在鸟饵猪油罐头陷阱中对蚊子进行抽样来确定。在这些设备中捕获的蚊子将被识别并解剖，以确定它们是否为经期蚊子，以及它们的卵巢是否可能滞育。我们将(1.3)确定这些淡色库蚊在卵巢滞育开始后是否继续寻找宿主，方法是试图将它们收集在定期设置在大型冬眠室的鸟饵猪油罐中，在那里记录它们的繁殖行为和寿命。一系列补充的实验室观察(1.4)将试图确定在不同纬度收集的蚊子后代是否因类似的Diels而进入和离开卵巢滞育，或者来自中纬度的蚊子滞育的时间是否比来自更北地点的蚊子的滞育时间短。下一步，实验室实验将试图确定卵巢发育和寻找宿主的行为是否受到类似环境线索的调控。最后，将探讨库蚊种群在南北轴线上的结构可能比东西轴线更明显的可能性。微卫星、RAPD和SSCP标记将从我们南北横断面以及800公里范围内的其他蚊子样本中进行分析。将调查近亲交配的自交种群的存在。总而言之，这些观察结果将定义这些媒介蚊子可能在美国北部放大西尼罗河病毒的持续时间，并将确定该时间段是否与白天长度或环境温度相关。