Ecological Niche of the 2003 West Nile Virus Epidemic in the Northern Great Plains of the United States
Figure 2
Environmental variables used in the final model of 2003 WNv incidence.
a) mean May–July temperature from 1971–2000, b) total May–July precipitation from 1971–2000, c) percent area of irrigated cropland, and d) percent of the population living in rural areas.