Epidemiology of Yellow Fever in the Americas

描述（由申请人提供）：本项目的总体目标 是评估城市（流行性）黄热病（YF）再次出现的风险， 美洲。由于城市化程度的提高， 蚊子媒介（埃及伊蚊）在大多数新热带城市，减少疫苗 覆盖面广，交通便捷，以及前所未有的人类活动水平 在YF病毒流行的丛林地区，现在主要关注的是， 这种疾病的流行或城市形式将在美洲重新出现。我们有 最近开发了一种YF仓鼠模型，它模拟了临床和 在人类严重形式的疾病中观察到的病理学表现 还有猴子使用仓鼠模型，将尝试验证 关于为什么城市青年基金会目前缺席的几个假设， 美洲.有四个具体目标，将测试假设，并将 研究新世界YF流行病学的各个方面。这些 包括对仓鼠的毒力和感染性的比较研究， 对埃及伊蚊的YF病毒的四种主要基因型进行了研究; 预先存在的异源黄病毒抗体在修饰 YF的严重程度;以及垂直（经卵巢） 在两种新大陆森林媒介（红腹血鼠和 Sabethes chioropterus）在维持地方性森林循环中的作用。项目 涉及病毒学、热带医学、病理学、医学 昆虫学和公共卫生。大部分工作将在实验室完成， 德克萨斯大学医学分支，热带疾病中心;但 一小部分将在巴西贝伦的Evandro Chagas研究所进行。

DESCRIPTION (provided by the applicant): The overall objective of this project is to evaluate the risk of urban (epidemic) yellow fever (YF) reappearing in the Americas. Because of increasing urbanization, the abundance of the urban mosquito vector (Aedes aegypti) in most Neotropical cities, decreasing vaccine coverage, rapid transportation, and the unprecedented level of human activity in jungle areas where YF virus is endemic, there is now major concern that the epidemic or urban form of the disease will reappear in the Americas. We have recently developed a hamster model of YF, which mimics the clinical and pathological manifestations observed in severe forms of the disease in humans and monkeys. Using the hamster model, an attempt will be made to validate several of the hypotheses of why urban YF is currently absent from the Americas. There are four specific aims, which will test the hypotheses and will examine various aspects of the epidemiology of YF in the New World. These involve comparative studies of the virulence for hamsters and the infectivity for Ae.aegypti of the four major genotypes of YF virus; an investigation of the role of pre-existing heterologous flavivirus antibodies in modifying the severity of YF; and an evaluation of the importance of vertical (transovarial) virus transmission in two New World sylvan vectors (Haemagogus janthinomys and Sabethes chioropterus) in maintenance of the enzootic forest cycle. The project involves the disciplines of virology, tropical medicine, pathology, medical entomology and public health. Most of the work will be done in laboratories at the University of Texas Medical Branch, Center for Tropical Diseases; but a small portion will be done at the Evandro Chagas Institute in Belem, Brazil.