Crews will spray for mosquitoes across Wheaton on Thursday, July 16, after the Wheaton Mosquito Abatement District confirmed West Nile Virus activity and high mosquito populations in the area.

The spraying will run from dusk until approximately 2 a.m., weather permitting, according to a City of Wheaton alert posted Monday, July 13.

The action comes amid what the Centers for Disease Control and Prevention has called the earliest start to the West Nile virus season in more than two decades. The CDC reported at least 48 human cases nationwide through June 30, 2026, the highest number at that point in the year since 2004 and nearly five times the typical average of 10 cases by the end of June. Of those 48 cases, 38 involved severe neuroinvasive disease.

Twenty-three states had reported West Nile virus activity as of June 30, 2026, also the highest number in the past 10 years, according to the CDC.

What residents should do Thursday evening

In Monday's alert, the city advised residents to take three steps:

Reduce exposure. Eliminate standing water in bird baths, flower pots, and old tires where mosquitoes breed. Fix tears in window screens. Avoid outdoor activity between dusk and dawn, when mosquitoes are most active.

Repel bites. Apply an EPA-registered insect repellent containing DEET, picaridin, oil of lemon eucalyptus, or IR3535.

Report problem areas. Flag stagnant water or flooded yards at www.clarkeportal.com. Residents can also sign up for spray notifications through the same portal.

Who is most at risk

Most people infected with West Nile virus do not develop symptoms, according to the CDC. About one in five develop fever, headache, body aches, or rash. Less than 1% develop severe neurologic disease. Adults 60 and older and people with certain underlying medical conditions face the highest risk.

About the district

The Wheaton Mosquito Abatement District is a separate entity from the City of Wheaton. It covers 23 square miles, including most of Wheaton as well as sections of Carol Stream, Glendale Heights, and unincorporated Milton Township. Clarke, the district's service contractor, manages the integrated mosquito control program.

To receive phone notifications before future spraying, residents can call Clarke's mosquito hotline at 1-800-942-2555.