The white-spotted mosquito and the northern house mosquito are believed to maintain the natural
transmission cycle of West Nile Virus between birds and mosquitoes in Illinois. Two types of climate models have been developed to provide an estimate of the likely date where the northern house mosquito begins to become the dominant species, and thus when the risk of WNV to horses, humans, and other wildlife is likely to increase.
The information provided here is based on recent research conducted by scientists at the Midwestern Regional Climate Center, Illinois State Water Survey and the Illinois Natural History Survey in association with the National Climatic Data Center.