Two women with West Nile virus have died, becoming the state's first deaths from the illness this year.
One woman was in her 70s and the other was in her 80s, according to reports from the Illinois Department of Health. Another two Chicago residents with the virus have recovered.
Statewide, health officials have reported 15 human cases of West Nile virus, which is transmitted by mosquitoes.
Last year, 11 people died in Illinois after being infected by the virus and 117 Illinois residents were diagnosed with it.
The virus can cause fever, headache and body aches. People age 50 and older are at a higher risk for serious complications.
Health officials recommend removing standing water where mosquitoes can breed, using insect repellent that contains DEET and repairing torn screens on doors and windows to combat the virus.