Lyme Disease

What is Lyme disease?

Lyme disease is caused by a bacteria, Borrelia burgdorferi, that is transmitted by a tick called Ixodes scapularis (commonly called the deer tick). Lyme disease may cause symptoms affecting the skin, nervous system, heart and/or joints of an individual. Approximately 6,000 cases of the disease have been reported in Wisconsin since surveillance for Lyme disease began in 1980.

Why is it called Lyme disease?

The first cluster of cases associated with this infectious agent was discovered near the town of Lyme, Connecticut.

Who gets Lyme disease?

Males and females of all ages can get Lyme disease. People who spend time outdoors in tick-infested environments are at an increased risk of exposure. Most cases have reported an exposure to ticks or woodland/brush habitat during the months of May through August, but cases have been reported during every month of the year. In Wisconsin, the vast majority of cases have been acquired in the western two-thirds of the state. The northwestern and westcentral portions of Wisconsin have the highest incidence of the disease.

How is Lyme disease spread?

The disease is acquired by a tick bite. The deer ticks which transmit the Lyme disease bacterium become infected when the immature stage of the tick feeds on infected field mice. When subsequent stages of that tick feed again, the infection can be transmitted to the tick's new host. The tick must actually be attached to a person's skin before it can transmit the bacterium. The bite of the tick is usually painless.

What are the symptoms of Lyme disease?

The illness usually occurs during the summer months and often starts as a roughly circular reddish rash 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 may last for several weeks. If left untreated, within a few weeks to months after the rash onset, complications such as meningitis, facial palsy, heart abnormalities, and arthritis may occur.

Swelling and pain in the large joints may recur over several months or years in untreated Lyme disease. Not all persons with the disease develop the initial skin rash.

How soon do symptoms occur?

The early symptoms usually begin within a month of exposure. The later arthritic, cardiac, and neurologic problems can take weeks to months to appear.

Does past infection with Lyme disease make a person immune?

Current information indicates that a person can get infected more than once.

What is the treatment for Lyme disease?

The disease is treated with antibiotics administered orally or by injection.

What can be done to prevent the spread of Lyme disease?

A vaccine against Lyme disease is available. Persons who live, work, or recreate in areas where the disease is prevalent AND who have extensive contact with tick habitat (woodland/brush) should ask their doctor about getting the vaccine. The current vaccine regimen consists of three injections and is about 80% effective in preventing Lyme disease after the third dose. The need for booster doses is unknown at this time. Because the effectiveness is not 100% and because tick bites can cause other diseases besides Lyme disease, even vaccinated persons should continue to take precautions to avoid tick bites.

If you are in areas where ticks may be present, the following precautions can reduce the risk of getting a tick bite and acquiring Lyme disease:

• Wear a long-sleeved shirt, long pants, and high socks with pant cuffs tucked into the socks. Light colored clothing will make ticks easier to find. Walk in the center of mowed trails to avoid brushing up against vegetation.

• Insect repellents containing 0.5% permethrin or 20-30% DEET have been shown to be effective in repelling deer ticks. If such products are used, be sure to follow the manufacturer's directions on the label.

• Conduct thorough "tick checks" on yourself and your children after spending time outdoors. Prompt removal of ticks, even after they have attached, can drastically reduce the chance of Lyme disease transmission.

How should a tick be removed?

To remove an attached tick, grasp it with narrow-bladed tweezers or forceps as close as possible to attachment (skin) site, and pull upward and out with a firm and steady pressure. If tweezers are not available, use fingers shielded with tissue paper or rubber gloves. Do not handle with bare hands. Be careful not to squeeze, crush or puncture the body of the tick which may contain infectious fluids. After removing the tick, thoroughly disinfect the bite site and wash hands. See or call a doctor if there is a concern about incomplete tick removal. It is important that a tick be properly removed as soon as it is discovered.

Each year, Medical College of Wisconsin physicians care for more than 180,000 patients, representing nearly 500,000 patient visits. Medical College physicians practice at Children's Hospital of Wisconsin, Froedtert Memorial Lutheran Hospital, the Milwaukee VA Medical Center, and many other hospitals and clinics in Milwaukee and southeastern Wisconsin.