Judith Ruiz-Branch, Producer
Wednesday, May 14, 2025
May is Lyme Disease Awareness Month and the latest state data show Wisconsin recently recorded the highest number of Lyme disease cases in state history.
Experts are urging residents to be mindful of the ticks carrying it as they become more active across the state. There are 16 confirmed tick species in Wisconsin and experts are focused on the "black-legged tick," or "deer tick," in the transmission of Lyme disease. Experts recommended taking preventive measures when spending time outdoors like wearing protective clothing and using insect repellent. They added you should perform tick checks and shower after any outdoor activity.
Dr. Xia Lee, public health entomologist at the Wisconsin Department of Health Services, said some ticks, especially younger ones, may be harder to spot.
"Those are usually the ones that we associate with a lot of the cases of Lyme disease or tick-borne diseases, most active in June and July," Lee explained. "This is also reflected in the number of people who go into the emergency department or go into the physician for tick bite-related illness."
The number of reported Lyme disease cases has tripled over the past 15 years, according to state data. Lee noted the Wisconsin Department of Health Services conducts surveillance and tracking of ticks for the public, including a tick identification service and a dashboard reporting ER visits for tick bites.
Deer ticks have spread from northwestern Wisconsin to every county in the state over the past 30 years. Experts said changes in land use, wildlife management and the environment have helped spread the disease.
PJ Liesch, entomologist at the University of Wisconsin-Madison, said the deer tick is a generalist feeder and can be found on many small mammals, in addition to deer. He added the increasing prevalence of the species has led to an emerging health threat.
"They are still spreading outwards," Liesch pointed out. "They seem to be moving into newer areas, in some cases that can be more like suburban backyards, areas where we haven't seen them historically. And they're still potentially expanding and we don't know when they are going to stop."
Liesch stressed if you are bitten by a tick in Wisconsin, there's about a 50-50 chance it is carrying Lyme disease. He emphasized the risk of Lyme disease transmission increases with the duration of tick attachment, which is why prevention and detection are so important.
"That's a pretty high rate of infectivity, kind of a scary number," Liesch acknowledged. "Even if you have a deer tick that is Lyme-positive, if you are checking yourself and making sure they are not attached to you for very long, that's going to greatly reduce the chances of transmission."
Some early symptoms of Lyme disease include fever, headache, fatigue, swollen lymph nodes, joint and muscle pain and a rash. If left untreated, more complicated conditions can develop.
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