Boone County mosquitoes test positive for West Nile virus

BELVIDERE, Ill. (WTVO) — Mosquitoes in Boone County have tested positive for West Nile Virus in 2025, according to the Boone County Health Department.

Authorities said the mosquitoes were collected in Belvidere on July 30th.

So far, Boone County has had no positive bird or human cases of West Nile Virus.

This year, there have been 3 reported cases of West Nile Virus in Illinois.

West Nile Virus is transmitted from the bite of a mosquito that has fed on an infected bird. The health department says 4 out of 5 people bitten by an infected mosquito will not get sick.

Those who do often experience fever, nausea, headache, and body aches within 3 to 14 days of being bitten. Serious illnesses, such as encephalitis or meningitis are possible, however

“The best way to prevent West Nile encephalitis and other mosquito-borne illnesses is to reduce the number of mosquitoes around your home and neighborhood and to take personal precautions to avoid mosquito bites,” said Amanda Mehl, Public Health Administrator of the Boone County Health Department.

The health department recommends the “Three Rs” to avoid becoming infected:

REDUCE exposure – avoid being outdoors when mosquitoes are most active, especially between dusk and dawn. Keep doors and windows closed. Eliminate sources of standing water where mosquitoes can breed, including wading pools, old tires, and other receptacles. Change bird bath water weekly.

REPEL – when outdoors, wear shoes and socks, long pants and a long-sleeved shirt. Apply EPA­ registered insect repellent that contains DEET, picaridin, oil of Lemon Eucalyptus, or IR3535 according to label instructions.

REPORT – The Health Department is monitoring freshly-dead birds, such as crows or blue jays. The birds must not show any signs of decay or trauma. To report a dead bird, call 815-544-2951. Be prepared to give the location, date and time you found the dead bird. You may also contact the Health Department to report areas of stagnant water in roadside ditches, flooded yards and similar locations that may produce mosquitoes. The Department is relying on county residents to help identify and report potential mosquito breeding areas in and around underdeveloped or abandoned residential building sites and swimming pools.