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: 6801491
• 负责人: Andrew Spielman
• 金额: $ 40.95万
• 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/6801491
• 关键词: Latitude; Duration; Neartic; WNV; Outbreaks

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个假设：西尼罗河病毒（WNv）在美国北部的传播力可能比在中纬度地区更大。为此，我们将确定库蚊繁殖季节的持续时间。 pipiens 蚊子是该地区 WNv 的主要维持媒介，其与纬度以及日长是否限制吸血和随后的繁殖活动的持续时间相关。首先（1），我们将定义这些蚊子在自然界中产卵和寻找宿主活动的季节性动态。 (1.1) 将通过记录 4 月至 10 月在美国东海岸北纬 34 度至 45 度横断面选定地点的采样装置中沉积的卵筏丰度来分析产卵活动。 (1.2) 马萨诸塞州波士顿附近吸血活动的季节性将通过在猪油罐诱鸟器中对蚊子进行采样来确定。这些装置中捕获的 C. pipiens 蚊子将被识别和解剖，以确定它们是否已生育以及它们的卵巢是否处于滞育状态。我们将（1.3）确定这些C. pipiens蚊子在卵巢滞育开始后是否继续寻找宿主，方法是尝试将它们收集到定期设置在大型冬眠处的鸟饵猪油罐陷阱中，记录它们的繁殖行为和寿命。一系列补充实验室观察（1.4）将试图确定在不同纬度收集的蚊子后代是否会响应类似的昼夜而进入和离开卵巢滞育，或者来自中纬度地区的蚊子是否比来自更北地区的蚊子以更短的昼夜滞育。接下来（2），实验室实验将试图确定卵巢发育和宿主探索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线上的结构可能比东西轴线上的结构更明显的可能性（3）。微卫星、RAPD 和 SSCP 标记将从沿南北样带采样的蚊子以及 800 公里空间内采样的其他蚊子中进行分析。将调查近交自体种群的存在。总而言之，这些观察结果将确定这些媒介蚊子可能在美国北部放大 WNv 的持续时间，并将确定该时期是否与白天长度或环境温度相关。