Mosquito in De Pere, August 30, 2021. PC: Fox 11 Online
(WTAQ-WLUK) — West Nile virus has been detected in a Shawano County resident.
According to the Shawano-Menominee Counties Health Department, the infection was confirmed in a “healthy blood donor” whose blood screened positive for WNV.
“The presence of a blood donor with WNV confirms that there are mosquitoes infected with WNV in the area that can spread the virus to other people and animals,” health officials said in a news release Thursday. “WNV activity has also previously been detected in people who have become ill from WNV, and in mosquitoes and animals in other parts of the state this year.”
This is the first confirmed human case of WNV in Northeast Wisconsin this year. The Wisconsin Department of Health Services reports there have been 14 human cases in western and southern counties, with 12 hospitalizations, so far in 2025.
WNV is spread to people, birds and other animals through the bite of an infected mosquito. The virus cannot be spread directly from person to person, animal to animal or animal to person.
About 80% of individuals who become infected with WNV don’t get sick. Those who do become ill usually experience mild symptoms like fever, headache, muscle ache, rash and fatigue.
Less than 1% of humans who contract WNV become seriously ill, with symptoms such as high fever, muscle weakness, stiff neck, disorientation, mental confusion, tremors, confusion, paralysis and coma. Older adults and people with compromised immune systems are at greater risk of developing severe illness from WNV. The virus can be fatal. If you suspect you may have WNV, contact your health care provider.
The Shawano-Menominee Counties Health Department says Wisconsin sees an average of 18 human WNV cases each year from June through October, with most infections reported in August and September.
The best way to protect yourself against WNV is by reducing your exposure to mosquitoes and eliminating mosquito breeding sites. It’s important to remember that mosquito activity and the risk of WNV will continue until there is a hard frost (temperatures below 28 degrees Fahrenheit for at least four straight hours).
Here are some tips from the Wisconsin Department of Health Services:
Avoid mosquito bites
- Apply an insect repellent with DEET, picaridin, oil of lemon eucalyptus or IR3535 to exposed skin and clothing
- Prior to heading outdoors, treat clothing with permethrin; do not apply permethrin directly to skin
- Consider rescheduling outdoor activities that occur during evening or early morning hours, when mosquitoes that spread WNV are most active
Mosquito-proof your home
- Prevent mosquitoes from breeding around your home by removing stagnant water from items around your property
- Empty standing water that has collected in tin cans, plastic containers, flower pots, discarded tires, roof gutters and downspouts
- Turn over wheelbarrows, kiddie pools, buckets and small boats such as canoes and kayaks when not in use
- Change the water in bird baths and pet dishes at least every three days
- Clean and chlorinate swimming pools, outdoor saunas, and hot tubs; drain water from pool covers
- Make sure window and door screens are intact and tightly-fitted to prevent mosquitoes from getting into your home
- Trim or mow tall grass, weeds and vines since mosquitoes use these areas to rest during hot daylight hours
Because most individuals who contract WNV don’t get sick, blood donors may occasionally and unknowingly donate blood while infected. However, to prevent spread of WNV through blood transfusions, all donated blood in the U.S. is tested for the virus. Any blood product that tests positive is removed from the blood supply.
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