The Knox County Health Department today, September 22, 2025, announced that a mosquito sample collected in Henderson Township has tested positive for West Nile Virus (WNV). This is the first positive sample of the season and indicates that the virus is active in the county.
“The confirmation of West Nile Virus in our community serves as an important reminder for residents to take proactive measures to protect themselves and their families from mosquito bites,” said Sarah Willett, Environmental Health Supervisor. We expect that mosquito activity will last through the remainder of the fall season. Currently, the Illinois Department of Public Health is reporting sixty-eight counties with positive humans, birds, mosquitoes, and/or horses, seventy-nine human cases and one human death in 2025.
The positive sample was collected by the Health Department on Friday, September 19, 2025, as part of its routine surveillance program.
The Health Department reminds individuals that preventing exposure to mosquitoes is the best way to avoid contracting the virus.” The Knox County Health Department recommends practicing the three “R’s” to the help fight against mosquitoes.
- REDUCE exposure – avoid being outdoors when mosquitoes are most active, especially between dusk and dawn.
- Make sure doors and windows have tight-fitting screens. Repair or replace screens that have tears or other openings. Try to keep doors and windows shut, especially at night.
- Avoid places and times when mosquitoes bite, before and after sunset and again just before dawn.
- Wear long sleeves and pants when in wooded areas. Keep pant legs tucked into boots or socks.
- Eliminate all sources of standing water where mosquitoes can breed, including water in bird baths, ponds, flowerpots, wading pools, pet’s water bowl, old tires, and any other receptacles.
- REPEL – when outdoors, wear shoes and socks, long pants, and a long-sleeved shirt, and apply insect repellent that contains DEET, picaridin, oil of lemon eucalyptus or IR 3535, according to label instructions. Consult a physician before using repellents on infants.
- REPORT – report locations where you see water sitting stagnant for more than a week such as roadside ditches, flooded yards, and similar locations that may produce mosquitoes. The Health Department may be able to add larvicide to the water, which may kill any mosquito eggs.
The Knox County Health Department will continue to conduct surveillance and take appropriate steps to monitor the mosquito population. For more information about West Nile Virus and how to protect yourself, visit www.knoxcountyhealth.org or call 309-344-2224.
***Courtesy of the Knox County Health Department***
