A batch of mosquitoes collected from Fox River Grove has tested positive for West Nile virus, the McHenry County Department of Health said Wednesday.
The mosquito pool was collected Friday and is the first positive test for West Nile virus in mosquitoes in McHenry County this year.
The health department said it would continue to collect and test mosquito batches throughout mosquito season. The season runs from May 1 to October 15 but West Nile risk runs until the first hard frost.
No human cases of the disease have been reported in the county this year, the department said.
Most people exposed to West Nile virus don’t develop symptoms, and there is no vaccine or treatment for it.
In positive cases, human illness typically happens two to 14 days after being bitten by an infected Culex mosquito.
About 20% of people with West Nile virus experience mild fever with other symptoms such as headaches, body aches, joint pains, vomiting or a rash. Mild symptoms can be relieved with rest, fluids and over the counter pain and fever medication.
Severe symptoms are very rare but include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.
Those 50 and older and people with serious underlying health conditions like diabetes, kidney disease, cancer, hypertension or have received an organ transplant are at greater risk for severe symptoms. If you or someone you know develops severe symptoms, the health department recommends seeking medical attention.
People are encouraged to eliminate standing water from containers around their home and make sure doors and windows have tight-fitting screens.
“Culex mosquitoes, which are the primary carriers of WNV, typically breed in stagnant water with high organic content, often found in artificial containers like rimless tires, abandoned swimming pools, buckets, bird baths, and clogged gutters,” the department said.
Residents are encouraged to wear protective clothing outdoors, including light-colored, long-sleeved shirts, socks and pants, to protect from mosquito-borne illnesses. Residents should also use EPA-registered insect repellents, according to the department.
Use EPA-registered insect repellents with one of the following active ingredients, and apply them according to label directions:
- DEET (N,N-diethyl-meta-toluamide)
- Picaridin (KBR 3023)
- IR3535 (a biopesticide)
- Oil of lemon eucalyptus (OLE)
- Para-menthane-diol (PMD)
- 2-undecanone
Consult with a doctor before using any repellent on infants. The United States Environmental Protection Agency (EPA) has compiled a list of EPA-registered repellents; visit ‘Find the Right Repellant that is Right for You’ on the EPA website.
For more information, visit mcdh.link/mosquitoes-wnv or call (815) 334-4585.