GENETIC VARIATION OF ST LOUIS ENCEPHALITIS VIRUS IN CA

这份新的R 03研究提案涉及PA-96-048，标题为扩展 圣路易斯脑炎（SLE）病毒的研究 自20世纪30年代以来一直活跃在加州，可能会重新- 在未来会成为严重的健康威胁。 这种病毒造成了 随着湿地的恢复，对加州的威胁越来越大， 发展项目及毗邻的康乐场地，以及 农药的使用越来越受到限制。 在蚊子 是活跃的，SLE病毒维持在包括野生 鸟类和蚊子媒介。 我们认为SLE病毒维持在 在加州的不利季节和年份， 具有周期性出现新基因型和/或周期性 从其他地方病流行区引进。 建议的目标 研究是使用分子遗传学方法来解决 SLE病毒的复发和扩散。系统发育分析 SLE病毒分离株的核苷酸和氨基酸序列 整个加州，并与其他病毒分离株进行比较， 包括密西西比河流域在内的美国部分地区， 东海岸和德克萨斯州，加勒比海，巴拿马，南部和中部 美国在很长一段时间内，将允许确定 SLE病毒基因型变化的速率，是否存在 恒定的分子变化或加速变化的事件，以及是否 病毒在不同的地理区域之间传播。 提出 研究验证了SLE病毒分离株在给定的 随着时间的推移，地理区域几乎没有遗传变化，这表明， 它们在这些区域持续存在，但新的基因型周期性地 引入或出现，与先前存在的 基因型 这项研究可能有助于解释出现的一种方式， 来自温带气候的地方病疫源地的黄病毒。

This new R03 research proposal addresses PA-96-048 entitled Expanded Research on Emerging Diseases St. Louis encephalitis (SLE) virus has been consistently active in California since the 1930's and may re- emerge in the future as a serious health threat. This virus poses an increasing threat to California as wetlands are restored, housing developments and recreational sites located adjacent to them, and the use of pesticides increasingly restricted. In seasons when mosquitoes are active, SLE virus is maintained in enzootic cycle involving wild birds and mosquito vectors. We proposed that SLE virus is maintained through adverse seasons and years in California by persistence in enzootic foci with periodic emergence of new genotypes and/or periodic introduction from other enzootic areas. The objective of the proposed research is to use a molecular genetic approach to address the recrudescence and dispersal of SLE virus. Phylogenetic analysis of nucleotide and amino acid sequences of SLE viral isolates from throughout California and a comparison with viral isolates from other sections of the United States including the Mississippi River Basin, East Coast and Texas, and the Caribbean, Panama, and South and Central America, over an extended period of time, will allow determination of the rate at which the SLE viral genotype is changing, whether there is constant molecular change or episodes of accelerated change, and whether the virus is being carried between discrete geographic areas. Proposed research tests the hypothesis that isolates of SLE virus in given geographic areas show little genetic change over time, suggesting that they persist in those areas, but new genotypes are periodically introduced or emerge which circulate with the previously existing genotype. This study may help explain one means of emergence of flaviviruses from enzootic foci in temperate climates.