West Nile virus found across 13 Illinois counties

As summer begins, the Illinois Department of Public Health is urging the public to remain vigilant about West Nile virus, now reported in 13 counties across the state.

The virus has been reported in Champaign, Cook, Douglas, Fulton, Kane, Hancock, La Salle, Morgan, Washington, Whiteside, Williamson, Winnebago and Woodford counties, according to a news release from the state.

No human cases of the virus have been reported in Illinois this year. In 2023, there were 119 cases and six deaths, compared with 34 cases and seven deaths in 2022, according to the release.

Health officials urge the public to “Fight the Bite” with National Mosquito Control Awareness Week from June 16 to 22.

“West Nile Virus can lead to serious illness, especially for our Illinois seniors and people with weakened immune systems,” IDPH Director Dr. Sameer Vohra said in the release. “With the virus appearing earlier this year following a milder winter and spring, I urge everyone to fight the bite in their communities. Please reduce exposures, wear insect repellent while outdoors, and report any standing water around your community where mosquitoes can breed.”

A county is considered positive for West Nile virus if a bird, mosquito, horse or human tests positive, with the first positive mosquito batches this year detected in mid-May, about two weeks earlier than usual, according to the release.

Updates on where cases have been reported can be found at dph.illinois.gov/topics-services/diseases-and-conditions/west-nile-virus/surveillance.

The IDPH is allocating $2.8 million to 97 local health departments for mosquito control, including larvicide application, virus prevention education and investigation of mosquito breeding sites and complaints. Local health departments will also collect mosquitoes and test sick or dead birds, horses and humans for the virus, according to the release.

Residents should report sick or dead crows, blue jays, robins or other perching birds to their local health department.

West Nile virus, transmitted by Culex mosquitoes from infected birds, can cause symptoms like fever, nausea, headache and muscle aches, lasting a few days to weeks. Most people show no symptoms, but severe cases can lead to meningitis, encephalitis or death, particularly in those over 60 or with weakened immune systems.

IDPH urges the public to Fight the Bite by practicing the three “R’s” – reduce, repel and report:

• REDUCE: Fix or replace torn screens and keep doors and windows closed. Eliminate or refresh standing water weekly in bird baths, ponds, flowerpots, wading pools, tires and other containers.

• REPEL: Wear shoes, socks, long pants and light-colored long sleeves outdoors. Use EPA-approved insect repellent. Consult a physician before using on infants.

• REPORT: Report stagnant water in ditches and flooded areas to local health authorities for larvicide treatment.