Mosquito batch in McHenry County tests positive for West Nile Virus

MCHENRY COUNTY, Ill. — Health officials in McHenry County say they have identified a mosquito batch that tested positive for West Nile Virus (WNV) this week.

According to officials from the McHenry County Department of Health (MCDH), a mosquito pool that was collected from Lake in the Hills, on Monday, June 2, tested positive for WNV.

It is the first WNV-positive mosquito batch located in the county so far this year.

Last week, mosquitoes from a batch found in Glenview tested positive for WNV.

Following the discovery of WNV-positive mosquito batches in Dupage County last year, health officials warned the public to follow the ‘4 Ds of Defense’ to avoid potential exposure:

Drain: Drain items that collect standing water around homes, yards, or businesses and scrub and refill pet water dishes and birdbaths regularly. 

Defend: Use insect repellents that contain DEET when outdoors and reapply according to directions. 

Dress: Wear long pants, long sleeves, and closed-toe shoes to cover the skin when outside. 

Dusk to Dawn: Wear EPA-registered insect repellent outdoors during these prime times for mosquito activity. 

According to the West Nile Virus dashboard maintained by the Illinois Department of Public Health, there have been no human cases reported in the state so far this year.

In 2024, the state saw 69 human cases, which resulted in 13 deaths.