Gorris M E, Cat L A, Zender C S, Treseder K K, Randerson J T
Department of Earth System Science University of California Irvine CA USA.
Department of Ecology and Evolutionary Biology University of California Irvine CA USA.
Geohealth. 2018 Jan 15;2(1):6-24. doi: 10.1002/2017GH000095. eCollection 2018 Jan.
Valley fever is endemic to the southwestern United States. Humans contract this fungal disease by inhaling spores of spp. Changes in the environment can influence the abundance and dispersal of spp., causing fluctuations in valley fever incidence. We combined county-level case records from state health agencies to create a regional valley fever database for the southwestern United States, including Arizona, California, Nevada, New Mexico, and Utah. We used this data set to explore how environmental factors influenced the spatial pattern and temporal dynamics of valley fever incidence during 2000-2015. We compiled climate and environmental geospatial data sets from multiple sources to compare with valley fever incidence. These variables included air temperature, precipitation, soil moisture, surface dust concentration, normalized difference vegetation index, and cropland area. We found that valley fever incidence was greater in areas with warmer air temperatures and drier soils. The mean annual cycle of incidence varied throughout the southwestern United States and peaked following periods of low precipitation and soil moisture. From year-to-year, however, autumn incidence was higher following cooler, wetter, and productive springs in the San Joaquin Valley of California. In southcentral Arizona, incidence increased significantly through time. By 2015, incidence in this region was more than double the rate in the San Joaquin Valley. Our analysis provides a framework for interpreting the influence of climate change on valley fever incidence dynamics. Our results may allow the U.S. Centers for Disease Control and Prevention to improve their estimates of the spatial pattern and intensity of valley fever endemicity.
山谷热在美国西南部地区呈地方性流行。人类通过吸入某种真菌的孢子而感染这种疾病。环境变化会影响该真菌的数量和传播，导致山谷热发病率出现波动。我们整合了各州卫生机构的县级病例记录，创建了一个美国西南部地区的山谷热数据库，涵盖亚利桑那州、加利福尼亚州、内华达州、新墨西哥州和犹他州。我们利用该数据集探究了2000年至2015年期间环境因素如何影响山谷热发病率的空间格局和时间动态。我们从多个来源汇编了气候和环境地理空间数据集，以便与山谷热发病率进行比较。这些变量包括气温、降水量、土壤湿度、地表尘埃浓度、归一化植被指数和耕地面积。我们发现，在气温较高且土壤较干燥的地区，山谷热发病率更高。美国西南部地区发病率的年平均周期各不相同，在降水量和土壤湿度较低的时期之后达到峰值。然而，从逐年情况来看，在加利福尼亚州圣华金谷春季较为凉爽、湿润且作物生长良好之后，秋季发病率较高。在亚利桑那州中南部，发病率随时间显著上升。到2015年，该地区的发病率是圣华金谷发病率的两倍多。我们的分析为解释气候变化对山谷热发病动态的影响提供了一个框架。我们的结果可能会使美国疾病控制与预防中心改进对山谷热地方性流行的空间格局和强度的估计。
