Feb 8, 2017

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

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
  • 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