Mosquitoes, Ticks, & Disease

About fifteen years ago, West Nile Virus disease arrived in Illinois. Lyme disease arrived here a few years earlier.  West Nile Virus is spread by a mosquito and Lyme disease is spread by a tick. Ticks and mosquitos can live only in areas that have the right temperature and the right amount of water – in other words, they can only cause disease in people if the climate is right for them. With climate warming, the “disease vectors” (the mosquitos and ticks) will be able to live in places that used to be too cold for them. Currently, the diseases of concern in Illinois are listed below with additional information about them.

Disease Vector
West Nile Virus Mosquito
Lyme disease Tick
Ehrlichiosis Tick
Rocky Mountain spotted fever Tick


The maps below show how the number of Lyme disease cases in the United States has increased from 1996 to 2012. Each blue dot represents one case – or a person who had Lyme disease. In 1996 there were only a few cases in northeast Illinois. By 2012, the northeast corner is almost all blue and there are several cases scattered throughout the State.

One way to help slow down diseases spread by mosquitos is to empty any large container that can hold water, such as tires. Insect repellents that contain DEET are also recommended.