Johnson Tammi L, Haque Ubydul, Monaghan Andrew J, Eisen Lars, Hahn Micah B, Hayden Mary H, Savage Harry M, McAllister Janet, Mutebi John-Paul, Eisen Rebecca J
Division of Vector-Borne Diseases, Centers for Disease Control and Prevention, 3156 Rampart Road, Fort Collins, CO 80521.
National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.
J Med Entomol. 2017 Nov 7;54(6):1605-1614. doi: 10.1093/jme/tjx163.
The mosquitoes Aedes (Stegomyia) aegypti (L.)(Diptera:Culicidae) and Ae. (Stegomyia) albopictus (Skuse) (Diptera:Culicidae) transmit dengue, chikungunya, and Zika viruses and represent a growing public health threat in parts of the United States where they are established. To complement existing mosquito presence records based on discontinuous, non-systematic surveillance efforts, we developed county-scale environmental suitability maps for both species using maximum entropy modeling to fit climatic variables to county presence records from 1960-2016 in the contiguous United States. The predictive models for Ae. aegypti and Ae. albopictus had an overall accuracy of 0.84 and 0.85, respectively. Cumulative growing degree days (GDDs) during the winter months, an indicator of overall warmth, was the most important predictive variable for both species and was positively associated with environmental suitability. The number (percentage) of counties classified as environmentally suitable, based on models with 90 or 99% sensitivity, ranged from 1,443 (46%) to 2,209 (71%) for Ae. aegypti and from 1,726 (55%) to 2,329 (75%) for Ae. albopictus. Increasing model sensitivity results in more counties classified as suitable, at least for summer survival, from which there are no mosquito records. We anticipate that Ae. aegypti and Ae. albopictus will be found more commonly in counties classified as suitable based on the lower 90% sensitivity threshold compared with the higher 99% threshold. Counties predicted suitable with 90% sensitivity should therefore be a top priority for expanded mosquito surveillance efforts while still keeping in mind that Ae. aegypti and Ae. albopictus may be introduced, via accidental transport of eggs or immatures, and potentially proliferate during the warmest part of the year anywhere within the geographic areas delineated by the 99% sensitivity model.
埃及伊蚊（双翅目：蚊科）和白纹伊蚊（双翅目：蚊科）传播登革热、基孔肯雅热和寨卡病毒，在美国部分已出现这两种蚊子的地区，它们对公共卫生构成的威胁日益增大。为补充基于不连续、非系统性监测工作得出的现有蚊子分布记录，我们利用最大熵模型，根据1960年至2016年美国本土各县的存在记录，将气候变量与之拟合，从而为这两种蚊子绘制了县级环境适宜性地图。埃及伊蚊和白纹伊蚊的预测模型总体准确率分别为0.84和0.85。冬季的累积生长度日数（GDDs）是整体温暖程度的一个指标，是这两种蚊子最重要的预测变量，且与环境适宜性呈正相关。根据敏感度为90%或99%的模型，被归类为环境适宜的县的数量（百分比），埃及伊蚊为1443个（46%）至2209个（71%），白纹伊蚊为1726个（55%）至2329个（75%）。提高模型敏感度会使更多县被归类为适宜地区，至少就夏季生存而言是这样，而这些县并无蚊子记录。我们预计，与较高的99%敏感度阈值相比，基于较低的90%敏感度阈值被归类为适宜地区的县中，会更常见地发现埃及伊蚊和白纹伊蚊。因此，敏感度为90%时预测为适宜的县应成为扩大蚊子监测工作的首要重点，同时仍要记住，埃及伊蚊和白纹伊蚊可能通过卵或未成熟个体的意外运输被引入，并可能在99%敏感度模型划定的地理区域内的任何地方，在一年中最温暖的时期繁殖。
