About Lyme Disease


If you live in Wisconsin, it is likely you or someone you know has been affected by Lyme disease. From 2016 through 2020, Wisconsin had an average of 3,519 cases of Lyme disease per year. The average number of reported cases has more than doubled over the past 15 years.

Lyme disease is an illness caused by the bacteria Borrelia burgdorferi, and rarely, Borrelia mayonii. It is spread to humans by the bite of an infected deer tick, also known as the black-legged tick. Lyme disease is the most commonly reported illness spread by ticks in Wisconsin. Deer ticks are present in all counties in Wisconsin.

Anyone can get Lyme disease, but people who spend more time outdoors are at a higher risk of being bitten by an infected tick. Ticks can be found in areas with woods, brush, or tall grass. Ticks are most active from May to November, but it is important to use caution year-round.

Check out our Lyme disease data page for more information. For specific, county-level data, please visit the easy-to-use Wisconsin Environmental Public Health Tracking portal.

  • Lyme Disease in Wisconsin 1990-1992

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 1993-1995

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 1996-1998

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 1999-2001

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 2002-2004

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 2005-2007

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
  • Lyme Disease in Wisconsin 2008-2010

     

    Lyme disease cases have increased in number and spread throughout the state over time. Lighter colors indicate fewer cases and darker colors indicate more cases.
 

 How is Lyme disease spread to humans?

Lyme disease is spread to humans through the bite of an infected deer tick.
  • A tick must be attached for at least 24 hours to spread Lyme disease to a person. It is important to remove ticks as soon as they are found to prevent illness.
  • Most humans are infected by immature ticks, called nymphs.Tick rests on a leaf
    • Nymphs are very small, about the size of a poppy seed. They are difficult to see, and most people may not feel their bite. This makes them harder to remove promptly.
    • Nymphs are most active during the spring and early summer.
  • Adult ticks also spread Lyme disease.
    • Adults are much larger than nymphs, and are more likely to be found and removed before the bacteria are spread to the person.
    • Adult ticks are most active during the cooler months.
  • Ticks can attach to any part of the body but are often found in hard-to-see areas, such as:
    • Behind the knees
    • Armpits
    • Scalp
    • In and around the ears
    • Inside the belly button
    • Groin

Lyme disease is preventable and treatable. Visit our Tick Bite Prevention page to learn how to prevent tick bites, and how to properly remove a tick if you are bitten.

 What are the signs and symptoms of Lyme disease?

BE ALERT FOR FEVER OR RASH. Even if you do not remember being bitten by a tick, a fever or rash may be the first sign of Lyme disease. Contact your health care provider right away if you have either of these symptoms.

Early symptoms can show up three to 30 days after being bitten by an infected tick.

Early signs and symptoms include:

  • Circular reddish rash, also known as erythema migrans (EM) rash
    • Occurs in about 70 to 80 percent of cases.
    • Expands in size over a period of days or weeks.
    • May clear in the center as it gets bigger, giving it a "bull's-eye" appearance.
    • NOTE: A small bump or redness at the tick bite site is common, and usually goes away in one to two days. This is not a sign of Lyme disease.
  • Fever, sweats, chills
  • Headache
  • Fatigue
  • Stiff neck
  • Muscle and/or joint pain
Later symptoms can show up weeks to months after being bitten by an infected tick.

If left untreated, Lyme disease can affect other body systems. Later signs and symptoms include:

  • Arthritis (joint swelling)
  • Meningitis (brain and spinal cord swelling)
  • Facial palsy (droop on one or both sides of the face)
  • Heart abnormalities
  • Nerve pain
  • Shooting pains, numbness, or tingling in the hands or feet

 How is Lyme disease treated?

Most people treated with oral antibiotics during the early stages of Lyme disease recover completely. It is important to get treatment as soon as possible after symptoms start. Antibiotics commonly used for oral treatment include doxycycline, cefuroxime axetil, or amoxicillin. The following table shows the current treatment recommendations from CDC for early stage Lyme disease in adults and children.

Treatment for Early Lyme Disease
Age Category
Drug
Dosage
Maximum
Duration, Days
Adults
Doxycycline
100 mg, twice per day orally
N/A
10–21
Adults
Cefuroxime axetil
500 mg, twice per day orally
N/A
14–21
Adults
Amoxicillin
500 mg, twice per day orally
N/A
14–21
Children
Amoxicillin
50 mg/kg per day orally, divided into three doses
500 mg per dose
14–21
Children
Doxycycline
4 mg/kg per day orally, divided into two doses
100 mg per dose
10–21
Children
Cefuroxime axetil
30 mg/kg per day orally, divided into two doses
500 mg per dose
14–21

If treatment is delayed, the bacteria can spread to the joints, heart, and nervous system and have long-term effects. Lyme disease can be difficult to treat in later stages, and severe cases may require intravenous treatment. Some people may have symptoms that will not go away or return even after appropriate antibiotic treatment, a condition called post-treatment Lyme disease syndrome (PTLDS).

 Resources

DHS Resources
CDC Resources
Partner Resources
Lyme disease is preventable and treatable. Visit our Tick Bite Prevention page to learn how to protect yourself from Lyme disease and other illnesses spread by ticks.

Questions about illnesses spread by ticks? Contact us!
Phone: 608-267-9003 | Fax: 608-261-4976

Last Revised: June 15, 2022