Mosquitoes In Will County Test Positive For West Nile Virus: Health Dept.

MOKENA, IL — Mosquitoes collected in Mokena are Will County's first to test positive for West Nile Virus this year, officials said.

The Will County Health Department’s Environmental Health division announced the finding Friday. Will County residents are reminded to protect themselves from mosquito bites and mosquito-borne diseases.

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No human cases of West Nile virus have been reported in Will County so far this year. According to data from the Illinois Department of Public Health (IDPH), WNV has been found in five counties in Illinois in 2026. There have been no confirmed human cases of WNV in the state so far in 2026.

WNV typically causes mild, flu-like symptoms. According to the Centers for Disease Control and Prevention (CDC), most people [8 out of 10] infected with West Nile virus do not develop any symptoms. About 1 in 5 people who are infected develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea, or rash. Most people who develop symptoms from WNV recover completely, but fatigue and weakness can last for weeks or months.

However, according to the CDC, about 1 in 150 people who are infected develop a severe illness that affects the central nervous system such as inflammation of the brain (encephalitis) or inflammation of the membranes that surround the brain and spinal cord (meningitis). Severe illness can occur in people of any age, however people over 60 years of age are at greater risk for severe illness if they are infected. People with certain medical conditions, such as cancer, diabetes, hypertension, kidney disease, and people who have received organ transplants, are also at greater risk.

Because there is no vaccine available to prevent West Nile virus, it is important to avoid mosquito bites.

The Will County Health Department and Illinois Department of Public Health encourages the public to “Fight the Bite” by practicing the “Three R’s” – reduce, repel, and report:

• REDUCE - 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. Eliminate, or refresh each week, all sources of standing water where mosquitoes can breed, including water in bird baths, ponds, flowerpots, wading pools, old tires, and any other containers.
• REPEL - when outdoors, wear shoes and socks, long pants and a light-colored, long-sleeved shirt, and apply an EPA-registered 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 local health department or city government may be able to add larvicide to the water, which will kill any mosquito larvae.

For more information on WNV and what can be done to prevent getting bitten by mosquitoes, visit the Centers for Disease Control and Prevention’s West Nile virus page at https:// www.cdc.gov/westnile/ or at the Illinois Department of Public Health’s West Nile Virus.