Lyme Disease


What is Lyme disease?

Lyme disease is a serious infection that affects the central nervous system, the cardiovascular system and the joints.  Lyme disease can effectively be treated with antibiotics if the infection is detected early enough.  Lyme disease is caused by the bacteria, Borrelia burgdorferi that is spread to people through the bite of an infected blacklegged tick (formerly called deer tick).These bacteria can be transmitted to humans after a female blacklegged tick has fed for 24 or more hours.

The City of Thunder Bay and immediately surrounding area are now considered a risk area for Lyme disease. More than 10% of the blacklegged ticks in this area are infected with Lyme disease bacteria.

Most ticks found in the Thunder Bay District are wood ticks and do not carry the Lyme disease bacteria.


What are ticks and how do they spread Lyme disease?

Wood ticks are the most common ticks found in the Thunder Bay and district; they are harmless to humans in our area but can be a nuisance.

The City of Thunder Bay and immediately surrounding area are now considered a risk area for Lyme disease. More than 10% of the blacklegged ticks in this area are infected with Lyme disease bacteria.

Ticks penetrate the skin with their mouthparts, draw blood, enlarge, and then drop off. The feeding tick's mouth will be under the skin, but the back parts will be sticking out. An infected blacklegged tick is most likely to transmit infection after being attached for more than 24 hours of feeding because the bacteria requires time to migrate from the tick’s gut to its salivary glands.  Because of this delay, early detection and removal of ticks is one of the key methods of preventing Lyme disease.  If a blacklegged tick is carrying the Lyme-causing bacteria and it is removed quickly from the body, it is very unlikely that it has transmitted Lyme disease to the host.


What are the symptoms of Lyme disease?

The symptoms of Lyme disease differ from person to person.  For more information, visit Ontario's Lyme disease website.


What should I do if I am concerned about a tick bite?

Speak with your health care provider/professional if you are concerned. Let them know any history of exposure to ticks (time spent outdoors), any rashes associated with the bite, travel history (to an area that is known for ticks) and possible exposure dates (when you might have been bitten).


What is the treatment for Lyme disease?

Antibiotics are effective in treating Lyme disease, especially if treatment starts early. See your health care provider/professional for more information.


How can I protect myself against tick bites?

Please click on Ticks & Lyme Disease for more information on prevention.


This page provides basic information only. It must not take the place of medical advice, diagnosis or treatment. Always talk to a health care professional about any health concerns.


For Further Information

Call the Environmental Health Program: (807) 625-5900

or toll-free 1-888-294-6630

Health Topic
Diseases & Infections