First human case of West Nile Virus reported in Dane County: Tips to protect yourself from mosquitoes

We're reporting our first human case of West Nile Virus (WNV) for the 2024 season. For context, there were 7 cases of WNV in Dane County last year, and six people have been diagnosed with WNV in Wisconsin this year.*

About 80% of people who are infected with WNV do not get sick. Those who do get sick usually have mild symptoms such as fever, headache, muscle ache, rash, and fatigue. Older adults and people with compromised immune systems (like transplant recipients) are at an increased risk of severe disease from the virus (encephalitis, meningitis, paralysis, coma, death). There is no specific medication for WNV but doctors can provide treatment to help reduce symptoms. If you think you have WNV, talk to your doctor.

The mosquitoes that spread WNV are most active during August and September. It’s not until we have a hard frost, or temperatures below 28 degrees for at least four consecutive hours, that mosquito activity dies down. The best way to protect yourself and your family from WNV and other diseases from mosquitoes is to reduce your exposure and eliminate mosquito breeding sites. Here’s how:

Use insect repellent

Use insect repellents on skin and clothing before heading outdoors during mosquito season (May-September). There are many repellent options available. The Wisconsin Department of Health Services recommends using repellents with at least one of the following:

• 20–30% DEET
• 10–20% picaridin
• 10–20% IR3535
• 30–40% oil of lemon eucalyptus

You can also use permethrin on your clothes and gear to kill mosquitoes (but do not use it on your skin directly). Permethrin can be toxic to cats when wet, so take care to apply it away from your feline friends. It’s also helpful to avoid being out at dawn and dusk, which are the most mosquito-heavy times of the day.

Wear long, loose-fitting clothing

If you are spending a lot of time outdoors (like hiking or on a fishing trip), think about long pants and sleeves. Loose-fitting and thicker clothing can also prevent mosquitoes from being able to reach your skin through your clothing. You can even wear a head net if you’re going into a mosquito-heavy area!

Get rid of standing water outdoors

Mosquitoes like to lay eggs in standing water. They only need a bit of shallow water, so be sure to keep your outdoor spaces dry or replace with fresh water often. Pesticide applications to kill mosquito larvae are also an option.

Mosquitoes can lay eggs in all sorts of places, including:

• Wheelbarrows
• Puddles that form on tarps
• The drainage trays in flowerpots
• Pet dishes
• Clogged gutters
• Leaves and other plant debris
• Birdbaths
• And more

Check your home’s screens

Make sure window and door screens don’t have any holes that mosquitoes can pass through.

*A previous version of this blog post said this was the fifth Wisconsin case of WNV this year. Another case in the state was confirmed on the same day, and we've updated the post to reflect six Wisconsin cases so far this year.