First Mosquito Batch To Test Positive For West Nile Discovered

McHENRY COUNTY, IL — Local health officials have discovered that a mosquito batch collected from Wonder Lake on Monday has tested positive for the West Nile Virus, which was also recently detected in a robin found in the county.

The mosquito batch was the first to test positive in McHenry County after a robin collected in unincorporated McHenry on July 22 also tested positive for the West Nile Virus, the McHenry County Health Department reported on Tuesday.

There have been five West Nile 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.

The McHenry County Department of Health conducts surveillance for West Nile Virus between May and October each year. Mosquito batch collections and testing are conducted weekly. In addition, the county health department collects a limited number of dead birds for testing each mosquito season.

Residents are asked to contact the health department if they 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 West Nile infection occurs this way, county health officials announced in a news release.

West Nile Virus is transmitted to humans predominantly through the bite of Culex mosquitoes, which is the primary vector for West Nile transmission in Illinois. 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. There is no vaccine available for West Nile Virus. It is important to remember that the risk of West Nile remains until the first hard frost.
The best way to prevent the virus 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:
• Insect repellents containing 20% or more DEET (less for children) are effective.
• Insect repellents including oil of lemon eucalyptus or Picaridin may be used as an alternative to DEET.
• 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.