The Impact of Climate and Climate Change on West Nile Virus Transmission

描述（由申请人提供）：拟议工作的长期目标是了解气候和病媒传播病原体传播之间的基本关系。我们将使用十多年的研究和数据，在多个尺度上对西尼罗河病毒（WNV）的传播生态，以确定气候对蚊子种群和WNV传播的机制关系以及气候变化的潜在影响。拟议的工作涉及三个具体目标：SA1）确定降雨和温度与人类，蚊子和鸟类中西尼罗河病毒发病率之间的大尺度时空相关性，同时控制土地使用。使用这些模式来产生关于产生这些相关性的局部尺度过程的机械假设。 我们将使用超过十年的WNV在鸟类，蚊子和人类中的发病率来确定温度和降雨量对WNV传播季节长度，WNV的空间分布和WNV传播强度的影响。SA2）用实验室研究和关于温度、降雨量、宿主丰度和西尼罗河病毒血清阳性率、蚊子丰度、喂养模式和西尼罗河病毒感染流行率的地方规模数据来检验关于气候传播联系的机制假设。 我们将进行实验室研究，以确定温度对媒介传播的病原体传播的四个关键因素的影响：媒介能力，发育率，寿命和三种主要的西尼罗河病毒蚊子的叮咬率。 我们将在横跨美国东西和南北方向的6个地区的182个地点进行西尼罗河病毒传播的当地研究，以确定降雨和温度对蚊子丰度和西尼罗河病毒传播强度相对于其他因素的影响。SA3）使用SA2支持的假设来预测气候变化对未来西尼罗河病毒传播的影响。我们将制定精细的未来气候预测，并利用目标1和2中获得的见解来预测气候变化对北美西尼罗河病毒分布、西尼罗河病毒传播季节长度以及美国各地传播强度的影响。 公共卫生相关性：气候变化对人类健康构成重大风险，包括病媒、水媒和食源性疾病、热应激、空气污染和极端天气事件。气候对病媒传播疾病的影响是较难解决的问题之一，因为气温升高和降雨量变化对病原体传播既有积极影响，也有消极影响，使简单的方向性预测变得脆弱。因此，要确定气候变化对病媒传播疾病的影响，就需要采取多尺度办法，确定气候对地方尺度传播的影响机制，然后将这些机制扩大到与公共卫生相关的尺度。目前和以前关于西尼罗河病毒的工作提供了一个机会，可以用这种多规模的方法正面解决这个问题，这将促进对这种疾病和其他病媒传播疾病的公共卫生干预。

DESCRIPTION (provided by applicant): The long range goal of the proposed work is to understand the fundamental relationships between climate and vector-borne pathogen transmission. We will use more than a decade of research and data at multiple scales on the transmission ecology of West Nile virus (WNV) to determine mechanistic relationships of climate on mosquito populations and WNV transmission and the potential impacts of climate change. The proposed work addresses three specific aims: SA1) Determine the broad scale spatio-temporal correlations between rainfall and temperature and West Nile virus incidence in humans, mosquitoes, and birds, while controlling for land use. Use these patterns to generate mechanistic hypotheses about local scale processes generating these correlations. We will use more than a decade of WNV incidence in birds, mosquitoes, and humans to determine the influence of temperature and rainfall on the length of WNV transmission season, the spatial distribution of WNV, and the intensity of WNV transmission. SA2) Test mechanistic hypotheses about climate-transmission links with laboratory studies and local scale data on temperature, rainfall, host abundance and WNV seroprevalence, and mosquito abundance, feeding patterns, and WNV infection prevalence. We will perform laboratory studies to determine the influence of temperature on four critical factors in the transmission of vector-borne pathogens: vector competence, developmental rate, longevity, and biting rate of the three dominant WNV mosquito species. We will use local studies of WNV transmission at 182 sites in 6 regions spanning the east-west and north-south dimensions of the USA to determine the influence of rainfall and temperature on mosquito abundance and the intensity of WNV transmission relative to other factors. SA3) Use hypotheses supported from SA2 to predict the impacts of climate change on future WNV transmission. We will develop fine scale future climate projections and use the insights gained from aims 1&2 to predict the effects of climate change on the distribution of WNV in North America, the length of the WNV transmission season, and the intensity of transmission across the USA. PUBLIC HEALTH RELEVANCE: Climate change presents important risks for human health, including, vector-borne, water-borne, and food-borne disease, heat stress, air pollution, extreme weather events. The impact of climate on vector-borne disease is one of the more difficult issues to address, because increasing temperature and changes in rainfall can have both positive and negative impacts on pathogen transmission, making simple directional predictions tenuous. As a result, determining the impact of climate change on vector-borne disease requires a multi-scale approach where the mechanisms of climate impacts on local scale transmission can determined, followed by a scaling up of these mechanisms to a scale that is relevant for public health. Current and previous work on West Nile virus presents an opportunity to attack the problem head-on with this multi- scale approach, which will facilitate public health intervention for this, and other vector-borne diseases.