Predictability of West Nile virus based on climate variables in Washington State

This study assesses the association between regional, monthly climate variables, including mean, minimum, and maximum temperature and total precipitation, with the following outcome variables: regional, monthly mosquito population size; regional, monthly West Nile Virus (WNV) mosquito maximum likelihood estimates (MLE); and regional, monthly human WNV incidence between 2007-2017. This study used data provided by NASA’s Goddard Earth Sciences Data and Information Services Center for climate data and the WA Department of Health for mosquito and human case data. The study plotted linear regressions of all of these associations using univariate analyses for every climate region of WA. Thus, regional, monthly climate was observed against regional, monthly mosquito population; regional, monthly mosquito MLE; and regional, monthly human WNV incidence, where county-level data were used as separate data points. This study found a negative relationship between regional, monthly precipitation and mosquito population, and a positive relationship between regional, monthly temperature and mosquito population. This study did not find any clear associations between regional, monthly climate and mosquito MLE or human WNV incidence. The study found a lack of association between regional, monthly mosquito population size and mosquito MLE, and a positive association between regional, monthly mosquito MLE and human WNV incidence.