West Nile virus is a viral disease affecting the central nervous system that can be transmitted to humans by mosquitoes. Photo: Pexels

Local health officials have confirmed the first positive case of West Nile virus in mosquitoes so far this year, and experts are offering tips on how you can prevent West Nile in your area.

Hamilton County Public Health (HCPH) announced Monday that the positive results came from mosquitoes trapped on June 17 in a residential area of Wyoming, a small city north of Cincinnati’s Hartwell neighborhood. The virus was found in mosquitoes only, and HCPH officials say there is no confirmed or probable human infection at this time.

Beginning July 7, the department will surveil the area and treat standing bodies of water with larvicide to prevent more mosquitoes from breeding. Some residents may also receive communications from specialists about mosquito concerns and get educational materials.

“Mosquitoes can transmit West Nile virus and other diseases through their bites, so it’s important to protect yourself both at home and when travelling,” said Jeremy Hessel, director of environmental health at HCPH. “Around Hamilton County homes, the best thing residents can do is to get rid of standing water, which mosquitoes use as their breeding grounds.” 

What is West Nile virus?

West Nile virus is a viral disease affecting the central nervous system that can be transmitted to humans by mosquitoes. HCPH said most people who are bitten by an infected mosquito will never become sick, but that everyone should be aware of the symptoms.

Symptoms may develop two to 14 days after someone is bitten by an infected mosquito. Mild symptoms include fever, headache, body aches, nausea, vomiting and sometimes swollen lymph glands or a skin rash on the chest, stomach and back.

Serious symptoms, which appear in less than one percent of those infected, include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis.

According to the U.S. Environmental Protection Agency, the average annual incidence of West Nile virus is highest in parts of the Southwest, the Mississippi Delta region, the Great Plains and the Rocky Mountain region. But studies show that warmer temperatures associated with climate change can accelerate the virus as mild winters and drought have been associated with West Nile virus disease outbreaks.

Preventing West Nile virus in your area

HCPH advises all residents to “Drain, Dunk and Protect” to reduce the mosquito population and prevent West Nile Virus:

Drain:

  • Look for and drain sources of standing water on your property – litter, tires, buckets, flowerpots, wading pools and similar items that could create standing water and become mosquito breeding sites.
  • Frequently change water in bird baths and pet bowls.
  • Drain small puddles after heavy rainstorms.

Dunk:

  • Apply mosquito larvicide, sometimes called mosquito “dunks,” to areas of standing water that cannot be drained. The “dunks” are environmentally safe and won’t harm pets. Purchase them at your local hardware store.

Protect:

  • Cut your grass and trim shrubbery.
  • Make sure screens in windows and doors are tight-fitting and free from defect.
  • Wear long sleeves and pants during peak mosquito hours – dawn and dusk.
  • Use an EPA-registered insect repellent such as those containing DEET, picaridin or oil of lemon or eucalyptus. Always follow the directions on the package.

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This article appears in Jun 25 – Jul 8, 2025.