WEDNESDAY, July 30, 2025 (HealthDay News) — Health officials have confirmed Wisconsin’s first human case of West Nile virus in 2025.

The case was found in Barron County, the Wisconsin Department of Health Services (DHS) said. Mosquitoes collected in both Milwaukee and Lafayette counties have also tested positive for the virus.

"The first detections of West Nile virus this year are a reminder to take steps to prevent mosquito bites and possible disease. West Nile virus poses a risk to all Wisconsinites, but people who have weakened immune systems are at higher risk for serious illness," State Health Officer Paula Tran told Fox 6 Milwaukee.

West Nile virus is spread to people and animals through the bite of an infected mosquito. 

Mosquitoes become infected when they feed on birds carrying the virus.

The virus is not spread from person to person or from animals to people.

Most people infected with West Nile virus do not feel sick. If symptoms do occur, they may include:

• Fever

• Headache

• Muscle aches

• Fatigue

• Chills

• Rash

In rare cases, people — especially older adults and those with weak immune systems — can develop serious illness. Severe symptoms include:

• High fever

• Muscle weakness

• Stiff neck

• Confusion or disorientation

• Tremors or seizures

• Paralysis

• Coma

The Wisconsin DHS recommends folks use insect repellent with DEET, picaridin, oil of lemon eucalyptus or IR3535 on skin and clothes to avoid bites.

It also recommends treating clothing with permethrin. 

Additional precautions include wearing long sleees, pants and socks when outside, and trying to avoid outdoor activities around dawn and dusk, which is when mosquitios are most active.

To mosquito-proof your home:

• Empty standing water from flowerpots, buckets, birdbaths, pet dishes, gutters and toys.

• Turn over canoes, kiddie pools and wheelbarrows when not in use.

• Keep swimming pools and hot tubs clean and chlorinated.

• Repair window and door screens if broken or cracked.

• Mow tall grass and trim weeds where mosquitoes rest during hot daylight temps.

More information

The U.S. Centers for Disease Control and Prevention has more on West Nile virus.

SOURCE: Fox 6 Milwaukee, July 28, 2025