WOOD RIVER — The Madison County Health Department confirmed the presence of West Nile virus in mosquito batches collected locally on July 3, 2025, health officials announced Monday, July 7, 2025.
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West Nile virus is transmitted to humans through the bite of an infected mosquito, which becomes infected by feeding on infected birds.
According to the Madison County Health Department, about 80% of people infected with the virus do not exhibit symptoms. When symptoms do occur, they may include fever, nausea, headache and muscle aches lasting from several days to a few weeks.
In rare instances, the virus can cause severe illness such as meningitis, encephalitis or death. Individuals over the age of 50 are at increased risk for serious complications.
To reduce the risk of infection, the health department recommends several preventive measures.
Residents are advised to avoid outdoor activities during peak mosquito activity times, particularly between dusk and dawn.
Wearing protective clothing such as shoes, socks, long pants and long sleeves is encouraged, along with the use of insect repellents containing DEET, picaridin, oil of lemon eucalyptus or IR3535, following label instructions.
Consultation with a doctor is recommended before applying repellents on infants.
Additionally, officials urge residents to ensure doors and windows have tight-fitting screens, repair or replace damaged screens, and keep doors and windows closed when possible.
Eliminating standing water where mosquitoes can breed — such as birdbaths, flowerpots, wading pools, and old tires — is also advised.
For more information, residents can visit the Madison County website at: www.madisoncountyil.gov.
