Mosquitoes Test Positive for West Nile Virus in Lake County

From The Lake County Health Department — Mosquito “pools” (batches of mosquitoes) sampled on June 27, 2023 in Bannockburn, Lake Villa, and Vernon Hills have tested positive for West Nile virus. These mosquito pools are the first confirmed indicators of West Nile virus presence in Lake County in 2023. 

“We expect mosquitoes every summer, but it is important to remember that they can also carry diseases like West Nile Virus,” said Mark Pfister, Executive Director of the Lake County Health Department and Community Health Center. “By learning to ‘Fight the Bite’, we can protect ourselves and our families from a potentially deadly disease.” 

Practice the “4 Ds of Defense” to protect yourself and your family from mosquitoes: 

Drain: Drain standing water from items around your home, yard, and business. 

Defend: When outdoors, use an insect repellent containing DEET, picaridin, oil of lemon eucalyptus, 2-undecanone, or IR3535 and reapply according to label directions. 

Dawn and Dusk: Protect yourself all day and night, and wear repellent outdoors during these prime times for mosquito activity. 

Dress: Wear long sleeves, pants, and closed toe shoes when outdoors to cover your skin. 

Culex pipiens mosquitoes, which are the primary carriers of West Nile virus, are most abundant when the weather is hot. Residents can help prevent these mosquitoes from breeding by eliminating areas of stagnant water from their properties. Items like buckets, gutters and plant containers, kiddie pools, and any other items holding water around homes and businesses can become breeding sites. 

The Lake County Health Department’s Mosquito Surveillance Program coordinates mosquito trapping results throughout Lake County. Mosquitoes are tested weekly for West Nile virus. The program also monitors reports of dead birds (an early sign of the presence of the virus) and investigates areas of stagnant water for the presence of mosquito larvae, specifically from the Culex mosquito, which is the primary carrier of West Nile in Illinois.  

“While the hot, dry weather results in fewer mosquitoes overall, the Culex mosquitoes that cause West Nile virus are still present,” said Alana Bartolai, Ecological Services Program Coordinator at the Lake County Health Department. "The years with the most cases of West Nile virus have often been during hot, dry summers.” 

In 2022, 81 mosquito pools tested positive for West Nile virus. Since 2002, there have been 79 confirmed human cases of West Nile virus in Lake County, as well as four confirmed deaths. 

Most people infected with West Nile virus have no symptoms of illness. However, some may become ill usually 3 to 15 days after the bite of an infected mosquito. Common symptoms include fever, nausea, headache and muscle ache. In some individuals, severe illness including meningitis or encephalitis, or even death, can occur. People older than 50 and individuals with weakened immune systems are at higher risk for severe illness from West Nile virus. 

Find more prevention tips and information on West Nile virus at www.FightTheBiteNow.com. Residents can also call the Health Department’s West Nile hotline to report areas of stagnant water, report locations of dead birds, and obtain more information on the signs and symptoms of West Nile virus. The West Nile hotline number is (847) 377-8300. 

For Immediate Release
Date: July 5, 2023
Contact: Emily Young
eyoung@lakecountyil.gov
(847) 377-8226