McHenry County Department of Health
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Mosquitoes test positive for West Nile virus

Post Date:06/21/2018 11:22 AM

Contact Keri Zaleski
815-334-4456; cell 815-236-3238

Woodstock IL – McHenry County Department of Health (MCDH) reports that a mosquito batch collected on June 18th from a mosquito trap in Woodstock tested positive for West Nile virus (WNV).  This is the first positive test for WNV collected by the Health Department in 2018.  No human cases have been reported in McHenry County.

 MCDH will continue to collect and test mosquito batches throughout the remainder of the season (mid-October) and will accept a limited number of dead birds for testing.  It is important to remember that the risk of WNV remains until the first hard frost. Residents should continue to use insect repellent when going out of doors in the evening and wear long sleeved shirts and long pants for extra protection.  Other tips include emptying standing water from containers around the house and making sure doors and windows have tight-fitting screens. 

 Illness from West Nile virus is usually mild and includes fever, headache and body aches but serious illnesses, such as encephalitis and meningitis and death, are possible.  Persons 50 and older have the highest risk of severe disease. 

The Health Department reminds residents that due to the recent flooding and rain there will continue to be large numbers of floodwater or nuisance mosquitoes. Although floodwater mosquitoes can be very aggressive, daytime biters, they are not significant vectors for human disease such as West Nile Virus in Illinois.

For more information on WNV, visit (Environmental Health) or call 815-334-4585.


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