Westmont, Illinois - Date Issued: July 17, 2023

The DuPage County Health Department (DCHD) has confirmed the first mosquito batches to test positive for West Nile Virus (WNV) this year in Dupage County, and is reminding residents to protect themselves from mosquito bites and the risk of contracting WNV.
The key factors in determining the degree of WNV activity are temperatures and rainfall. In hot, dry weather, mosquitoes that carry West Nile Virus (primarily Culex mosquitoes) breed in areas with stagnant water, such as street catch basins, ditches, birdbaths, flowerpots, and buckets, where the mosquitoes multiply rapidly.
“This summer, take action to protect yourself and your family from West Nile virus by preventing mosquito bites,” said Adam Forker, DCHD Executive Director. “Fight the Bite when spending time outdoors by using insect repellent, draining standing water, and limiting outdoor exposure from dusk to dawn.”
This year, there have been no reported human cases of WNV in DuPage County to date. However, the identification of positive mosquito pools is associated with an increased risk of WNV in people. Additionally, the recent hot, dry weather is an ideal environment for mosquitoes (primarily Culex mosquitoes) that spread WNV.
THE 4 D’s OF DEFENSE AGAINST MOSQUITOS
Protect yourself and your family - Prevent mosquitoes from breeding around your home by following the “4 Ds of Defense”:
- Drain: Drain items that collect standing water around your home, yard, or business. Scrub and refill pet water dishes and birdbaths regularly (at least weekly).
- Defend: Use an insect repellent containing DEET when outdoors and reapply according to directions.
- Dress: Wear long pants, long sleeves, and closed-toe shoes when outside to cover the skin.
- Dusk to Dawn: Wear repellent outdoors during these prime times for mosquito activity.
DUPAGE PERSONAL PROTECTION INDEX
Residents can also check the Personal Protection Index (PPI) on the DuPage County Health Department’s website for the current WNV activity. The PPI ranges in risk level from zero-to-three, with zero being no activity and three reflecting multiple human cases of WNV in DuPage County. The PPI is updated every Wednesday at 3:00 p.m. throughout the WNV season by the Health Department’s vector-borne disease surveillance experts.
WNV activity generally decreases in the fall when cooler temperatures arrive and especially after the first frost of the season. Additional statewide information and data can be found at the Illinois Department of Public Health’s West Nile virus website and the West Nile virus Dashboard.
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