This summer has brought warnings about cases of mosquito-borne illnesses, including malaria, dengue and Eastern equine encephalitis. But West Nile virus continues to be the leading cause of viral disease spread by insects.
West Nile spreads as mosquitoes bite infected birds and then people, making both bird and mosquito populations important parts of public health surveillance for the disease.
The United States has seen a flurry of West Nile virus deaths reported in the last few days, including most recently in Illinois, Nebraska and Colorado.
In the US, West Nile virus is leading cause of viral disease spread by insects, new CDC study says cnn.com - get the latest breaking news, showbiz & celebrity photos, sport news & rumours, viral videos and top stories from cnn.com Daily Mail and Mail on Sunday newspapers.