Health Officials Urge Wisconsinites to Protect Themselves From Mosquito Bites

Wednesday, July 30th, 2025 -- 9:01 AM

(Anna Marie Yanny, Wisconsin Public Radio) Health officials urge Wisconsinites to protect themselves from mosquito bites after a man from Barron County, north of Eau Claire, recently got sick from West Nile virus.

According to Anna Marie Yanny with the Wisconsin Public Radio, the virus is spread by mosquitoes and can cause flu-like symptoms. Officials also reported mosquitos in Milwaukee and Lafayette counties recently tested positive for West Nile virus.

The man, in his 60s, was the first case detected in Wisconsin this season. The state averages 18 cases per year, according to tracking by the Wisconsin Department of Health Services.

Most people who are infected by the virus will not have symptoms, the department’s vectorborne disease epidemiologist Rebecca Osborn, told reporters Monday.

“Nearly 80 percent of people who are infected with West Nile virus will never know it,” she said. “Many of us are probably walking around already having been exposed.”

Still, it’s important for Wisconsinites to take precautions to protect themselves, she added. For people 60 and over or those immunocompromised, the illness caused by the virus can be severe and even fatal. Symptoms can include fever, rash, headache, body aches and in extreme cases convulsions and coma.

“If you do start to feel sick with flu-like symptoms in the middle of the summer, and you know you’ve been exposed to mosquitoes, it could be something like West Nile virus,” Osborn said. “So it’s important to talk to your doctor.”

The virus is typically transmitted from birds to mosquitoes, which can then bite and infect humans. It cannot be spread from human to human. Wisconsin is coming out of a drought, which can mean more mosquitos, said PJ Liesch, an extension entomologist at the University of Wisconsin-Madison.

“We finally hit the point where no parts of Wisconsin are experiencing drought anymore. That’s a good thing for plants and crops, but … that can mean more mosquitoes out and about.” Liesch said.

“So recent reports that I’ve had at the UW Insect Diagnostic Lab do suggest that there’s quite a bit of mosquito activity out there in Wisconsin, although it can vary from location to location.”

Not all mosquito bites come with a risk of West Nile virus, he added. “In Wisconsin, we actually have around 55 different species of mosquitoes, and not all mosquitoes can transmit West Nile,” Liesch said.

“There are certain particular species that are the main drivers of this. And then there are other mosquitoes that may bite you, but they’re not carrying it. ” Interestingly, researchers tend to see more cases during years with drier conditions, he said, because certain types of mosquitoes prefer it.

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