Delineating EEEV Over-Wintering and Early Season Amplification Mechanisms

描述（由申请人提供）：东部马脑脊髓炎病毒（EEEV）是美国最具致病性的虫媒病毒。人类EEE病例虽然散发且难以预测，但非常严重，超过35%的有症状病例是致命的，大多数幸存者患有长期的神经系统并发症。佛罗里达州是美国EEEV活动最多的州，占所有报告的人间病例的25%，最近的证据表明，佛罗里达州是EEEV传播到其他州的水库。目前还没有针对EEEV的有效治疗方法或FDA批准的疫苗。因此，预防感染依赖于监测以发现病毒传播，然后采取措施试图防止病毒向人类传播。这些措施的有效性取决于对EEEV传播动态的理解，而这种理解仍然有限。特别是，研究人员一直无法确定EEEV如何和在哪里越冬，以及它如何从冬季周期转变为鸟类宿主的地方性放大。了解佛罗里达EEEV越冬和季前扩增的机制将使我们能够预测这些过程可能发生的时间和地点。这将导致有可能制定在季节早期中断传播的战略，这可能会在夏季晚些时候减少或防止EEEV的爆发，因为那时蚊子密度较大，干预成本相应较高。此外，如果佛罗里达州成为全国其他地区EEEV的蓄水池，那么早期季节干预可以通过防止EEEV从佛罗里达州传播到其他州来保护该国的大部分地区。为实现这一总体目标，提出以下具体目标：为了验证蛇是eev重要的越冬宿主的假设。2. 目的：初步确定佛罗里达地区EEEV冬季和早春地方性传播的宿主和媒介。为了验证涉禽栖息地是EEEV扩增的重要焦点的假设。4. 制定佛罗里达州早季EEEV传播风险图。这样的风险图对于预测EEEV越冬和季前扩增的疫源地将是无价的，允许制定有效的季前干预策略。

DESCRIPTION (provided by applicant): Eastern equine encephalomyelitis virus (EEEV) is the most pathogenic arbovirus endemic to the USA. Human cases of EEE, although sporadic and difficult to predict, are very serious, with over 35% of symptomatic cases being fatal and most survivors suffering long term neurological complications. Florida has the most EEEV activity in the US, with 25% of all reported human cases, and recent evidence suggests that Florida is a reservoir from which EEEV is disseminated to other states. There is no effective treatment or FDA approved vaccine for EEEV. Thus, prevention of infection relies upon surveillance to detect viral transmission, followed by measures to try to prevent the spread of the virus to humans. The effectiveness of these measures rests upon an understanding of the dynamics of EEEV transmission, and this understanding remains limited. In particular, researchers have been unable to determine how and where EEEV over-winters, and how it transitions from its winter cycle into enzootic amplification in avian hosts. Gaining an understanding of the mechanisms of over-wintering and early-season amplification of EEEV in Florida will allow us to predict when and where these processes may be occurring. This will lead to the possibility of developing strategies to interrupt transmission early in the season, which may lessen or prevent outbreaks of EEEV later in the summer, when mosquito densities are greater and the costs for intervention correspondingly higher. Furthermore, if Florida serves as the reservoir for EEEV for the rest of the country, early season interventions may protect much of the country by preventing dissemination of EEEV from Florida to other states. To accomplish this overall goal, the following Specific Aims are proposed: 1. To test the hypothesis that snakes are important over-wintering hosts for EEEV. 2. To delineate the hosts and vectors of winter and early spring enzootic transmission of EEEV in Florida. 3. To test the hypothesis that wading bird rookeries represent important foci for EEEV amplification. 4. To develop a risk map for early season EEEV transmission in Florida. Such a risk map will be invaluable in predicting foci of EEEV over-wintering and early season amplification, permitting the development of effective early season intervention strategies.