A spatially resolved and environmentally informed forecast model of West Nile virus in Coachella Valley, California.

Abstract

West Nile virus is the most significant arbovirus in the United States in terms of both morbidity and mortality. West Nile exists in a complex transmission cycle between avian hosts and the arthropod vector, Culex spp. mosquitoes. Human spillover events occur when humans are in close proximity to vector populations with high rates of infection. Predicting these rates of infection and therefore the risk to humans is not straightforward. In this study, we evaluate the hydrological and meteorological drivers associated with mosquito biology and viral development to determine if these associations can be used to forecast seasonal West Nile risk in the Coachella Valley of California. To test this, we developed and tested a spatially-resolved ensemble forecast model of West Nile virus transmission in the Coachella Valley using 17 years of mosquito surveillance data and NLDAS-2 environmental data. Our multi-model inference system indicated that the combination of a cooler and dryer winter followed by a wetter and warmer spring and a cooler than normal summer was most predictive of West Nile positive mosquitoes in the Coachella Valley. The ability to make accurate early season predictions of West Nile risk could allow local abatement districts and public health entities to implement early season interventions such as targeted adulticiding and public messaging before human transmission occurs. Such early and targeted interventions could better mitigate the risk of West Nile virus to humans in the Coachella Valley.

Exploring the role of temperature and other environmental factors in West Nile virus incidence and prediction in California counties from 2017-2022

“…In all, an ecological study was sufficient and better applicable to calculate the association of interest at the county level, while remaining easily replicable to future researchers and public health departments. More types of climatic analysis can be conducted using this same data, such as the effect of prior seasonal rainfall and temperature on future WNV incidence, the importance of which has been shown for the length of the WNV season in the US as a whole [21,22]. Exploring the mechanisms that mediate the association between temperature and West Nile virus would also be beneficial to further analyze different intervention strategies.…”

A Spatially Resolved and Environmentally Informed Forecast Model of West Nile Virus in Coachella Valley, California

“…NLDAS data is freely available from NASA (NLDAS, 2012). Our code, figures, data, and methodology can be accessed via (Ward, Patel, & DeFelice, 2023), and the statistical software R and cited packages can be obtained from the R Project for Statistical Computing (R Core Team, 2023)…”

“…NLDAS data is freely available from NASA (NLDAS, 2012). Our code, figures, data, and methodology can be accessed via (Ward, Patel, & DeFelice, 2023), and the statistical software R and cited packages can be obtained from the R Project for Statistical Computing (R Core Team, 2023). Mosquito data supporting this research are available from the Coachella Valley Mosquito and Vector Control District through VectorSurv under memorandum of understanding and are not accessible to the public or research community without prior approval (VectorSurv [Database].…”