Lake County Gazette

Lake County, Illinois, has reported its first human case of neuroinvasive West Nile virus for 2025. The individual affected is a resident in their 70s who became ill earlier this month.

"Our time spent outdoors typically increases during the summer months, which also increases our exposure to mosquitoes," stated Chris Hoff, Executive Director of the Lake County Health Department and Community Health Center. He urged residents to take protective measures against mosquitoes to lower the risk of contracting West Nile virus.

In 2025, nine out of 214 mosquito batches have tested positive for West Nile virus in the area. The virus tends to peak during late summer when mosquito populations are at their highest.

Symptoms of West Nile virus infection often appear three to 15 days after being bitten by an infected mosquito and can include fever, nausea, headache, and muscle aches. In rare cases, it can cause severe neurological symptoms such as encephalitis or meningitis. Older adults and those with weakened immune systems are at greater risk for serious illness.

For more information on prevention and signs of West Nile virus, residents can contact the Health Department’s hotline at (847) 377-8300.