May 3, 2023

Lyme disease cases on the rise in Wisconsin

Mite on child's hand. Dangerous tick on the skin crawls along the arm.

MADISON, Wis. – The number of reported cases of Lyme disease has more than doubled in Wisconsin over the past 15 years, according to the latest data from the Wisconsin Department of Health Services.

Lyme disease is a serious bacterial infection spread by blacklegged ticks, also known as deer ticks. In Wisconsin, Lyme disease is most common in late spring and summer, with most cases seen in May and June, according to Dr. Gregory DeMuri, pediatric infectious disease physician and professor of pediatrics at the University of Wisconsin School of Medicine and Public Health.

Data collection, public awareness and climate change are all factors as to why cases are on the rise, he said.

“Wisconsin reports one of the highest number of cases of Lyme disease in the country because they thrive in Wisconsin’s geographical terrain very well, and because we are having warmer winters and ticks are surviving better,” DeMuri said. “We also have a much better tracking system in place to keep the public aware.”

There were nearly 5,000 reported cases in 2021 in Wisconsin and when spring days turn warmer and wetter, a new generation of ticks emerge, he said.

It’s important to be familiar with the blacklegged tick’s appearance. Many health clinics offer tick identification cards.

They live in yards, low grasslands, wooded areas and anywhere that is also habitat for white-footed mice, also called deer mice, other small mammals and deer. That includes most of Wisconsin, DeMuri said.

“Ticks are now as likely to be found in parks and backyards as they are in northern woods,” he said. “Be aware and be prepared. Ticks are in all 72 counties in Wisconsin.”

Children ages 5 to 9 are most impacted by Lyme disease, according to DeMuri.

“Children are lower to the ground and the grass is higher up on their body so there are more opportunities for the ticks,” he said. “Children also have weaker immune systems and are susceptible to infection in general.”

A tick bite transfers bacteria through the tick’s mouth into the bloodstream. Symptoms of Lyme disease occur three to 30 days after the tick bite, according to DeMuri.

Up to 80% of infected people get a bulls-eye-shaped rash that spreads over several days and can reach 12 inches across. Other symptoms include flu-like symptoms such as chills, headache, fatigue and muscle and joint aches. Swollen lymph nodes can occur without the rash, he said.

If you discover a tick, it is important to remove it within the first 24 hours to greatly reduce your chance of getting Lyme disease. When removing the tick, keep the head and mouth intact and save them in a jar so they can be tested and identified, according to DeMuri.

“It is important to call your doctor right away if you find a tick, because if Lyme disease is detected early, antibiotics are very effective treatments for both children and adults,” he said.

“There can be long-term issues if you don’t seek care right away, including severe headaches and neck stiffness, arthritis, and brain and heart impairment.”

To avoid tick bites DeMuri recommends:

  • Wear appropriate clothing: Wear long, light-colored pants with the bottoms secured by tape.

  • Ticks will crawl up pants legs.

  • Apply insect repellents: DEET or picaridin-based repellents are recommended for the skin. Permethrin spray is recommended to use on clothing.

  • Conduct a thorough body check: Look everywhere on the body carefully including ears, feet, hair and swimsuit areas.

  • Check pets, especially dogs, for ticks as they can carry them into the house.