Day Jonathan F, Shaman Jeffrey
University of Florida, Institute of Food and Agricultural Sciences, Florida Medical Entomology Laboratory, 200 9th St. SE, Vero Beach, FL 32962, USA.
J Med Entomol. 2008 May;45(3):458-65. doi: 10.1603/0022-2585(2008)45[458:uhctft]2.0.co;2.
The accurate forecasting and tracking of arboviral transmission is becoming increasingly critical for the early recognition and management of arboviral epidemics. Meteorological factors, especially rainfall and temperature, drive arboviral epidemics, but monitoring rainfall and temperature alone is not predictive of increased levels of vector-borne disease transmission. In Florida, model simulations of water table depth (WTD) provide a measure of drought, and they have been shown to provide an accurate forecast of arboviral transmission. Here, we tracked WTD in two peninsular Florida regions where focal West Nile virus (family Flaviviridae, genus Flavivirus, WNV) transmission was reported during 2004 and 2005. We compared the resulting WTD profiles with historical WTD simulations for Indian River County (IRC), FL, where two peninsular Florida St. Louis encephalitis virus epidemics had their epicenters in 1977 and 1990. In both of the regions where focal WNV transmission was reported during 2004 and 2005, the local WTD profiles approached the 1977 and 1990 IRC WTD profiles; however, differences in the local temporal sequence of hydrologic conditions were observed. These differences seem in part to explain why the focal WNV transmission during 2004 and 2005 failed to reach epidemic levels in peninsular Florida. These findings suggest that hydrologic monitoring, specifically WTD, may help determine the geographic extent, timing, and intensity of WNV transmission. We speculate that a more precise sequence of drought and wetting, including a secondary summer drying and wetting cycle, as occurred in IRC during 1977 and 1990, may provide the optimal hydrologic conditions for the expansion of an arbovirus outbreak from focal to epidemic. This study documents that monitoring hydrologic conditions, along with vector, avian amplification host, and virus population data, increases our ability to track and predict significant levels of arboviral transmission.
对虫媒病毒传播进行准确预测和跟踪，对于虫媒病毒疫情的早期识别和管理愈发关键。气象因素，尤其是降雨和温度，会引发虫媒病毒疫情，但仅监测降雨和温度并不能预测病媒传播疾病水平的上升。在佛罗里达州，地下水位深度（WTD）的模型模拟可衡量干旱情况，且已证明能准确预测虫媒病毒传播。在此，我们跟踪了佛罗里达州半岛两个地区的地下水位深度，2004年和2005年期间这两个地区报告了西尼罗河病毒（黄病毒科黄病毒属，WNV）的局部传播。我们将所得的地下水位深度剖面与佛罗里达州印第安河县（IRC）的历史地下水位深度模拟结果进行了比较，1977年和1990年佛罗里达州半岛的两起圣路易斯脑炎病毒疫情均以该县为中心。在2004年和2005年报告有西尼罗河病毒局部传播的两个地区，当地的地下水位深度剖面接近1977年和1990年印第安河县的地下水位深度剖面；然而，观察到了当地水文条件时间序列上的差异。这些差异似乎在一定程度上解释了为何2004年和2005年佛罗里达州半岛的西尼罗河病毒局部传播未达到疫情级别。这些发现表明，水文监测，特别是地下水位深度监测，可能有助于确定西尼罗河病毒传播的地理范围、时间和强度。我们推测，1977年和1990年印第安河县出现的包括夏季二次干湿循环在内的更精确的干湿序列，可能为虫媒病毒疫情从局部爆发扩展至流行提供最佳水文条件。本研究证明，结合病媒、鸟类扩增宿主和病毒种群数据监测水文条件，可增强我们跟踪和预测虫媒病毒显著传播水平的能力。
