Predicting disease risk from community context and host phenotype: A trait-based approach

该奖项是根据2009年《美国复苏和再投资法》(公法111-5)资助的。该项目将测试个人感染传染病的风险是否由宿主个体(即宿主表型)和其他潜在感染源的宿主物种的少数几个容易测量的生态特征(社区背景)决定。实验将使用多宿主媒介传播病原体的模型系统进行：大麦黄矮病病毒、传播它们的蚜虫(昆虫)媒介和20种野草宿主物种。首先，温室实验将量化这些草种在低氮(养分)有效性和高氮(养分)有效性条件下的表型。表型将根据一系列生理性状进行量化，包括光合作用速率、叶片中营养物质的浓度、叶片生长速度和叶片寿命。营养浓度高的寄主也有高代谢率(包括快返或QR表型)，而营养浓度低的寄主代谢率低(慢返或SR表型)。温室试验还将测试QR表型是否比SR表型更大量地被蚜虫取食，更容易被取食的蚜虫感染，以及是否比SR表型更能抵御感染的负面影响。田间实验将测试QR表型是否比SR表型面临来自其他寄主物种的疾病传播的更大风险，以及这种风险是否取决于社区背景。野外实验将测试人类活动的一个主要结果--养分供应的增加是否会改变疾病风险。预测疾病风险是一个重要的生态、农业和公共卫生目标。特别令人担忧的是感染多种寄主物种的病媒传播疾病。例如，西尼罗河病毒主要通过以受感染的鸟类(宿主)为食的蚊子(媒介)传播给人类(宿主)。同样，大多数作物的病原体也会侵染野生植物寄主物种。了解风险来源将改善对野生和家养动植物以及人类疾病的管理。该项目将涉及本科生和研究生，结果将传达给从当地高中生到公共卫生专业人员的公民。

This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).This project will test whether an individual's risk of acquiring an infectious disease is determined by a handful of easily measured ecological traits of the host individual (i.e., host phenotype), and of other host species that are potential sources of infection (community context). Experiments will be conducted using a model system for multi-host vector-borne pathogens: barley yellow dwarf viruses, aphid (insect) vectors that transmit them, and 20 wild grass host species. First, greenhouse experiments will quantify the phenotypes of these grass species at low and high nitrogen (nutrient) availability. Phenotypes will be quantified based on a suite of physiological traits including rate of photosynthesis, concentration of nutrients in leaves, leaf growth rate, and leaf lifespan. Hosts with high nutrient concentrations are expected to also have high metabolic rates (comprising quick-return or QR phenotypes) while hosts with low nutrient concentrations will have low metabolic rates (slow-return or SR phenotypes). Greenhouse experiments will also test whether QR phenotypes are more heavily fed upon by aphids, are more susceptible to infection by feeding aphids, and are better able to withstand the negative impacts of infection than SR phenotypes. Field experiments will test whether QR phenotypes experience greater risk than SR phenotypes of disease transmission from other host species, and whether that risk depends on community context. The field experiments will test whether increased nutrient availability, a major result of human activities, alters disease risk. Predicting risk of disease is a critical ecological, agricultural, and public health goal. Of particular concern are vector-borne diseases that infect multiple host species. For example, West Nile virus is transmitted to humans (hosts) chiefly by mosquitoes (vectors) that fed on infected birds (hosts). Similarly, most pathogens of crops also infect wild plant host species. Understanding sources of risk will improve management of diseases in wild and domestic plants and animals, as well as humans. This project will involve both undergraduate and graduate students, and results will be communicated to citizens ranging from local high school students to public health professionals.