From the McHenry County Health Department:

Mosquitoes test positive for West Nile Virus in McHenry County

WOODSTOCK — A mosquito batch collected from Wonder Lake tested positive for West Nile Virus (WNV) on Monday.

A robin collected in unincorporated McHenry on July 22also tested positive for WNV, but this is the first positive batch of mosquitoes in McHenry County for the 2020 season. There have been 5 WNV positive birds, 265 positive mosquito batches and 0 reported human cases in Illinois so far this year, according to the Illinois Department of Public Health (IDPH).

From May through October, the McHenry County Department of Health (MCDH) conducts WNV surveillance. Mosquito batch collections and testing are conducted weekly. In addition, the MCDH collects a limited number of dead birds for testing each mosquito season. Contact the Division of Environmental Health at 815-334-4585 if you find a dead crow, blue jay or other perching bird. Bird specimens must be in good condition in order to be tested (no signs of insects, obvious injury or decay). Avoid touching the dead animal with bare-hands, although there is no evidence WNV infection occurs this way.

WNV is transmitted to humans predominantly through the bite of Culex mosquitoes, which is the primary vector for WNV transmission in Illinois. Illness from WNV 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. There is no vaccine available for WNV. It is important to remember that the risk of WNV remains until the first hard frost.

The best way to prevent WNV is to reduce the number of mosquito breeding sites around your home and to take personal precautions. 

·         Empty standing water from containers around the house (tires, neglected swimming pools, bird baths, clogged gutters and buckets); make sure doors and windows have tight-fitting screens.

·         Limit outdoor activities when Culex mosquitoes are most active (dusk, dawn) and wear long sleeved shirts and long pants for extra protection.

·         Use and apply insect repellents per label directions:

o    Insect repellents containing 20% or more DEET (less for children) are effective.

o    Insect repellents including oil of lemon eucalyptus or Picaridin may be used as an alternative to DEET.

o    Apply repellents per label directions. Consult with a doctor before using any repellent on infants.

For more information on mosquitoes and West Nile Virus, visit the Division of Environmental Health’s website under Nuisance Control at www.mcdh.info or call 815-334-4585.