First Human Case of West Nile Virus in Illinois this Season
The Center for Disease Control and Prevention (CDC) has confirmed Illinois’ first human case of West Nile virus (WNV) of 2025 in an individual from Southern Illinois who was hospitalized due to complications of the infection.
The case marks the earliest onset of illness observed in Illinois since 2016, and underscores the risk posed by mosquito bites, especially to those who are over 65 or immunocompromised.
IDPH urges 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, IR 3535, para-menthane-diol (PMD), or 2-undecanone 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.