EID: Plague As a Model for Low Prevalence/epizootic Disease Dynamics

当气候变化影响宿主的密度、宿主之间的接触和疾病传播以及传播疾病的昆虫种群的数量时，就会出现植物和动物自然种群中传染病的暴发。在这些广泛的模式中，疾病如何从爆发条件转变为低水平持续性尚不清楚。鼠疫是一种由鼠疫耶尔森氏菌引起的啮齿动物疾病，它为研究散布在几乎无法检测到疾病的间歇期的疾病爆发提供了一个理想的机会。鼠疫传入北美后，影响了大平原以西的大多数啮齿动物。黑尾土拨鼠是草原上群居的穴居啮齿动物，在疫情爆发时死亡率很高。科罗拉多州的长期研究表明，在厄尔尼诺年份，鼠疫爆发更为常见。该项目旨在确定鼠疫是否在水库宿主（其他啮齿动物）中持续存在，在草原土拨鼠或其跳蚤中保持低水平，或者只是在天气相关的其他啮齿动物密度增加后才从其他栖息地进入草原。将通过捕获啮齿动物和跳蚤来研究感染途径，并结合遗传指纹识别鼠疫疫源地。这些数据将为探索疾病持续性和传播的模型提供价值。鼠疫仍然是一个人类健康问题；全世界每年报告的病例多达3000例。这项研究为减少美国西部不断扩大的人口中的疾病发病率提供了关键信息。它也是短草草原长期生态研究项目鼠疫长期监测的一部分。来自城市，种族多样化的本科机构（加州州立大学富勒顿分校）的学生将获得独特的野外生态学经验，这增加了他们追求科学事业的可能性。

Outbreaks of infectious diseases in natural populations of plants and animals arise when variation in climate influences density of hosts, contact and disease transmission between hosts, and the size of insect populations that transmit disease. Within these broad patterns, how a disease changes from outbreak conditions to low-level persistence is unknown. Plague, a disease of rodents caused by the bacterium Yersinia pestis, provides an ideal opportunity for studying disease outbreaks interspersed within lulls when disease is almost undetectable. After its introduction into North America, plague has affected most rodent species west of the Great Plains. Black-tailed prairie dogs, burrowing rodents living in social colonies on grasslands, suffer high mortality during outbreaks. Long-term studies in Colorado show that plague outbreaks are more common during El Nino years. This project aims to determine whether plague persists in reservoir hosts (other rodents), remains at low levels within prairie dogs or their fleas, or only moves into grasslands from other habitats following weather-related increases in densities of other rodents. Routes of infection will be studied by trapping rodents and fleas, combined with genetic fingerprinting to identify plague foci. These data will provide values for models that explore disease persistence and transmission. Plague continues to be a human health concern; up to 3,000 worldwide cases are reported yearly. This research provides key information for minimizing disease incidence in the expanding populations of the western US. It is also part of long-term plague surveillance through the Shortgrass Steppe Long-Term Ecological Research project. Students from an urban, ethnically diverse undergraduate institution (Cal-State Fullerton) will gain unique experiences in field ecology, which increases the likelihood they will pursue careers in science.