Lyme Disease

Lyme disease is an illness caused by a bacterium, Borrelia burgdorferi, transmitted to humans by a tiny tick named Ixodes scapularis (commonly called the deer tick).  Lyme disease may cause signs and symptoms affecting the skin, nervous system, heart, and / or joints of an infected person.  More than 12,000 cases of the disease have been reported in Wisconsin residents since surveillance for Lyme disease began in 1980.

Information for health professionals

• Algorithm for Lyme disease case report classification  (PDF, 111 KB)

Information for general public

• Lyme disease fact sheet

Why is it called Lyme disease?

The first cluster of human illnesses associated with this bacterium was described near the town of Lyme, Connecticut during the mid 1970's.

Who gets Lyme disease? 

Males and females of all ages can get Lyme disease but children less than 16 years old and adults more than 40 years old appear to be at higher risk. People who spend time outdoors in tick-infested environments are at increased risk of exposure and exposure can occur whenever the temperature at ground level is warm enough for ticks to be active. In Wisconsin, most cases have occurred among persons living in the western half of the state.

How is Lyme disease spread? 

In Wisconsin, the disease is acquired by a tick bite from an infected deer tick. See image of deer tick (exit DHS) 
The bite of a tick is usually painless. Only nymph and female adult deer ticks transmit Lyme disease to humans and the tick must be attached for at least 24 hours to transmit the disease.

What are the symptoms of Lyme disease? 

Most Lyme disease case patients report their symptoms beginning during the late spring and summer months (May through August). The illness often, but not always, starts as a roughly circular reddish rash (called erythema migrans) around or near the site of the tick bite. The rash expands in size over a period of days or weeks. During the rash stage, other symptoms such as fever, headache, fatigue, stiff neck, muscle and/or joint pain may be present. These signs and symptoms may last for several weeks. If left untreated, complications such as meningitis, facial palsy, heart abnormalities, and arthritis may occur within a few weeks to months after the initial onset of symptoms.

How soon do symptoms occur? 

Early symptoms usually begin within a month of exposure. Arthritic, cardiac, and neurologist complications may take weeks or months to appear in untreated persons.

Does past infection with Lyme disease make a person immune? 

Although past infection provides some immunity, this immunity is relatively short-lived. Therefore it is possible for a person to get infected more than once.

What is the treatment for Lyme disease? 

The disease is treated with oral or injectable antibiotics. Lyme disease is more easily treated when detected early. Exposed persons should monitor their health and promptly see a health care provider if signs and symptoms consistent with Lyme disease (such as erythema migrans rash) develop. Remember, an infected tick must be attached for >24 hours to successfully transmit B. burgdorferi to humans.

Is there a vaccine to prevent infection? 

No. Although there had been a vaccine against human Lyme disease, this vaccine is no longer marketed.

Lyme disease  |  Prevention  |  Additional Resources  
  Surveillance  |  Surveillance-Historical  
Other tick-borne diseases

For information about Lyme disease in your community 
contact your local health department or:

Last Revised: October 22, 2009