CHICAGO – It’s National Mosquito Control Awareness Week, and health officials in Illinois are reminding the public that mosquitoes have appeared earlier this year due to a milder winter and spring, and with that comes the risk of West Nile.

At present, the Illinois Department of Public Health (IDPH) reports that 13 counties around the state have reported positive mosquito samples: Champaign, Cook, Douglas, Fulton, Kane, Hancock, LaSalle, Morgan, Washington, Whiteside, Williamson, Winnebago, and Woodford. Washington County, located approximately 55 miles east of St. Louis, is the closest of the aforementioned counties.

No human cases of West Nile virus have been reported in Illinois thus far in 2024. Last year, the IDPH reported 119 human cases and six deaths, while there were 34 human cases and seven deaths reported in 2022.

A county is considered positive for West Nile if a bird, mosquito batch, horse, or human from that county tests positive for the virus. The IDPH confirms 11 positive mosquito pools and 10 positive birds in the 13 counties. Labs across the state will test mosquito batches and dead birds, as well as sick horses and humans presenting West Nile-like symptoms. Anyone who sees a sick or dead crow, blue jay, robin, or other perching bird is asked to contact their local health department for testing.

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The health department is reminding everyone they can reduce their exposure by staying indoors when mosquitoes are most active, eliminating sources of standing water, and keeping doors and windows shut in the evening. When outdoors, you can wear long clothing or wear insect repellent with DEET.

The virus is spread through the bite of a mosquito that picked up the virus while feeding on an infected bird.

The CDC says that most people infected with the West Nile virus do not develop any symptoms. About 1 in 5 people who are infected develop a fever with other symptoms such as headaches, body aches, joint pains, vomiting, diarrhea, or rash. Serious illness, such as encephalitis and meningitis, is possible.

The most serious cases of West Nile can be deadly.

People ages 60 and older and people with weakened immune systems are more at risk of getting sick.