Department of Earth and Environmental Sciences, California State University East Bay, Hayward, California 94542, United States.
Department of Geography, University of California, Los Angeles, Los Angeles, California 90095, United States.
Environ Sci Technol. 2021 Jan 5;55(1):478-487. doi: 10.1021/acs.est.0c05857. Epub 2020 Dec 15.
The California state government put restrictions on outdoor residential water use, including landscape irrigation, during the 2012-2016 drought. The public health implications of these actions are largely unknown, particularly with respect to mosquito-borne disease transmission. While residential irrigation facilitates persistence of mosquitoes by increasing the availability of standing water, few studies have investigated its effects on vector abundance. In two study sub-regions in the Los Angeles Basin, we examined the effect of outdoor residential water use restrictions on the abundance of the most important regional West Nile virus vector, . Using spatiotemporal random forest models fit to abundance during drought and non-drought years, we generated counterfactual estimates of abundance under a hypothetical drought scenario without water use restrictions. We estimate that abundance would have been 44% and 39% larger in West Los Angeles and Orange counties, respectively, if outdoor water usage had remained unchanged. Our results suggest that drought, without mandatory water use restrictions, may counterintuitively increase the availability of larval habitats for vectors in naturally dry, highly irrigated settings and such mandatory water use restrictions may constrain abundance, which could reduce the risk of mosquito-borne disease while helping urban utilities maintain adequate water supplies.
加利福尼亚州政府在 2012-2016 年干旱期间对户外住宅用水（包括景观灌溉）实施了限制。这些行动对公共健康的影响在很大程度上是未知的，特别是对于蚊媒疾病的传播。虽然住宅灌溉通过增加积水的可用性来促进蚊子的持续存在，但很少有研究调查其对媒介丰度的影响。在洛杉矶盆地的两个研究子区域，我们研究了户外住宅用水限制对最重要的区域西尼罗河病毒媒介 的丰度的影响。使用适合干旱和非干旱年份 的丰度的时空随机森林模型，我们生成了在没有用水限制的假设干旱情况下 的丰度的反事实估计。我们估计，如果户外用水保持不变，西洛杉矶和橙县 的丰度将分别增加 44%和 39%。我们的结果表明，在自然干燥、高度灌溉的环境中，没有强制性用水限制的干旱可能会反直觉地增加幼虫栖息地对媒介的可用性，而这种强制性用水限制可能会限制 的丰度，从而降低蚊媒疾病的风险，同时帮助城市公用事业维持充足的水供应。
