West nile virus prevalence across landscapes is mediated by local effects of agriculture on vector and host communities

PLoS One. 2013;8(1):e55006. doi: 10.1371/journal.pone.0055006. Epub 2013 Jan 30.


Arthropod-borne viruses (arboviruses) threaten the health of humans, livestock, and wildlife. West Nile virus (WNV), the world's most widespread arbovirus, invaded the United States in 1999 and rapidly spread across the county. Although the ecology of vectors and hosts are key determinants of WNV prevalence across landscapes, the factors shaping local vector and host populations remain unclear. Here, we used spatially-explicit models to evaluate how three land-use types (orchards, vegetable/forage crops, natural) and two climatic variables (temperature, precipitation) influence the prevalence of WNV infections and vector/host distributions at landscape and local spatial scales. Across landscapes, we show that orchard habitats were associated with greater prevalence of WNV infections in reservoirs (birds) and incidental hosts (horses), while increased precipitation was associated with fewer infections. At local scales, orchard habitats increased the prevalence of WNV infections in vectors (mosquitoes) and the abundance of mosquitoes and two key reservoir species, the American robin and the house sparrow. Thus, orchard habitats benefitted WNV vectors and reservoir hosts locally, creating focal points for the transmission of WNV at landscape scales in the presence of suitable climatic conditions.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Agriculture / statistics & numerical data*
  • Animals
  • Bird Diseases / epidemiology*
  • Bird Diseases / transmission
  • Birds / virology
  • Climate
  • Culex / physiology*
  • Female
  • Horse Diseases / epidemiology*
  • Horse Diseases / transmission
  • Horses / virology
  • Humans
  • Insect Vectors / physiology*
  • Prevalence
  • Spatial Analysis
  • West Nile Fever / epidemiology
  • West Nile Fever / transmission
  • West Nile Fever / veterinary*
  • West Nile virus / physiology*

Grant support

This study was supported by United States Department of Agriculture (USDA) Agriculture and Food Research Initiative Project 2011-67012-30718 and USDA Risk Avoidance and Mitigation Program Project 2006-0207436. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.