Health officials are warning the public after a batch of mosquitoes tested positive for West Nile virus for the first time this year in McHenry County.
A mosquito “pool,” also known as a batch of mosquitoes, was sampled on Tuesday in Lake in the Hills and tested positive for West Nile virus.
The McHenry County Department of Public Health said this mosquito pool is the first confirmed indicator of West Nile virus presence in McHenry County in 2022.
Four birds were submitted for testing from McHenry County so far this year and all have been negative for the virus.
One bird and 108 mosquito batches have been positive this year in Illinois.
“Infected birds can become carriers of WNV through the bite of an infected mosquito and then pass the virus onto mosquitoes that feed on them. WNV is transmitted to humans predominantly through the bite of Culex mosquitoes, the primary vector for West Nile Virus transmission in Illinois,” the health department said.
Illness from West Nile virus is usually mild and includes fever, headache and body aches but serious illnesses, such as encephalitis, meningitis and death, are possible.
Persons 60 and older have the highest risk of serious illness, health officials said. There is no vaccine available for WNV.
Officials in nearby Lake County recommend the public practice the “4 Ds of Defense” to protect themselves and 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.
From May through October, McHenry County health department staff conduct West Nile surveillance throughout McHenry County. Mosquito batch collection and testing are conducted weekly.