Lyme Disease

What is Lyme Disease?

Lyme disease is a bacterial disease that is transmitted to humans and animals by the bite of an infected deer tick (also called the black-legged tick). The illness may affect the skin, joints, nervous system, heart and other areas of the body.

Minnesota’s Forests Have Beauty, Wildlife.. And Lyme Disease

  • According to the Centers for Disease Control, there were 914 cases of Lyme disease reported in Minnesota in 2006, the eighth highest number among all states. Our neighbors in Wisconsin had even more cases reported in 2006 – 1,466.
  • During the 10 year period from 1997 - 2006, there were 5,921 confirmed cases of Lyme disease in Minnesota.
    Although persons of all ages and genders are susceptible to tick bites,
  • Lyme disease is most common in the U. S. among boys ages 5-19 and persons ages 30 or older.
  • Lyme disease has also been diagnosed in dogs, cats, horses, goats, sheep and cattle. If left untreated, it can damage an animal’s eyes, heart, kidneys and nervous system.

The risk of exposure to tick-borne diseases in Minnesota is highest in the shaded areas of this map (To the right), according to 2006 information from the Minnesota Department of Health.


Signs and Symptoms in Humans

Recognizing the early signs and symptoms of Lyme disease is important. If you have one or more of these signs and symptoms within three to 30 days after a deer tick bite, see your physician immediately:

  • Within 1 to 2 weeks of being infected, people may have a bull’s-eye skin rash – a red ring with a central clearing, although not all rashes have a central clearing.
  • Some people have Lyme disease and do not have any early symptoms.
  • Fever and chills
  • Muscle and joint pain
  • Fatigue
  • Headache

If a person is not treated early in the disease, these late signs and symptoms may develop weeks, months or years after the tick bite:

  • Multiple rashes
  • Facial paralysis on one side
  • Weakness, numbness or pain in arms and legs
  • Irregular heartbeat
  • Memory, concentration problems
  • Chronic arthritis in one or more joints, usually the knees, which may be swollen and painful.

Signs and Symptoms in Animals

Lyme disease can affect individual pets differently. If left untreated, the disease may damage the eyes, heart, kidneys and nervous system.

Infected dogs may be lethargic, have a poor/loss of appetite or a fever (103°-105°F). Dogs may also experience lameness shifting from one joint to another, fatigue, kidney damage or failure, heart disorders or neurological involvement (e.g. aggression, confusion, overeating, seizures). Dogs can be infected but not exhibit any noticeable symptoms.

Cats may show lameness, fever, loss of appetite, fatigue, eye damage, unusual breathing or heart involvement. Many cats do not show noticeable symptoms, despite being infected.

Many cattle do not display signs of Lyme disease; those that do may have lameness, painful or swollen joints, fever, laminitis, or weight loss. A skin rash may be present on the udder of infected cows.

Infected horses generally do not have a fever, but may have lame or stiff joints, laminitis, or depression or may refuse to eat. This bacterial infection may be a cause of moon blindness or loss of vision. Many horses may be infected but display no symptoms.