Sara H. Paull, Daniel E. Horton, Moetasim Ashfaq, Deeksha Rastogi, Laura D. Kramer, Noah S. Diffenbaugh, A. Marm Kilpatrick

Proceedings of the Royal Society of London B: Biological Sciences

Published date February 8, 2017

Drought and immunity determine the intensity of West Nile virus epidemics and climate change impacts

  • Uses analyses at national and state scales to examine a suite of climatic and intrinsic drivers of continental-scale West Nile virus epidemics, including an empirically derived mechanistic relationship between temperature and transmission potential that accounts for spatial variability in vectors
  • Finds that drought was the primary climatic driver of increased West Nile virus epidemics, rather than within-season or winter temperatures, or precipitation independently
  • Finds that local-scale data from one region suggested drought increased epidemics via changes in mosquito infection prevalence rather than mosquito abundance
  • Finds that human acquired immunity following regional epidemics limited subsequent transmission in many states.
  • Shows that over the next 30 years, increased drought severity from climate change could triple West Nile virus cases, but only in regions with low human immunity
  • These results illustrate how changes in drought severity can alter the transmission dynamics of vector-borne diseases