• What is Lyme disease?
• How is Lyme disease transmitted?
• What are the signs and symptoms of Lyme disease?
• Can Lyme disease be treated?
• How do I know if I have a tick bite?
• Are some locations more at risk than others?
• What tests are available for Lyme disease?
• Who is at risk?
• How can Lyme disease be prevented?

What is Lyme disease?

Lyme disease is caused by bacteria called Borrelia burgdorferi. This bacterium is carried by certain ticks, and spreads to the host when the tick bites. The bacterium is normally found in small animals such as mice, squirrels, chipmunks, shrews, etc.

Lyme disease in humans can have a range of effects from rashes and flu-like symptoms to more serious symptoms including arthritic, cardiac and neurological effects. It can often be effectively treated, especially if detected in the early stages.

Lyme disease is an occupational concern for people who work outdoors. Any person who spends time outdoors is also at risk.

In the United States, Lyme disease is the most common "vector borne" disease. (Vector is the term for any insect or arthropod that carries and transmits a disease pathogen (virus, bacteria, etc.)).

How is Lyme disease transmitted?

Ticks usually live in woods or tall grasslands in Canada, the United States, Europe and Asia. Ticks infected with Borrelia burgdorferi spread the disease when they feed on blood from the host. Ticks cannot fly - they hang onto small bushes or tall grasses and are usually found close to the ground. They wait for an animal or person to pass near them and when the animals or person make contact, the ticks attach themselves to the skin to feed.

In North America, Lyme disease is transmitted (spread) mainly by two species of ticks:

• the blacklegged tick (sometimes called the deer tick), Ixodes scapularis, found primarily in southern and eastern Ontario, southeastern Manitoba and Nova Scotia, and eastern United States, and
• the western blacklegged tick, Ixodes pacificus in the western pacific regions such as southern British Columbia.

What are the signs and symptoms of Lyme disease?

Tick bites are usually painless and most people do not know they have been bitten. Signs and symptoms of Lyme disease vary greatly from person to person.

In the first stage, one of the first signs of infection is a circular rash, often referred to as a "bull's eye" rash because it will have rings spreading from the bite site (known as erythema migrans). Other rashes may occur. Rashes do not appear in every case of Lyme disease infection. Reports of rashes appearing range from 70-80% of infected people to as low as 30-50% in adults and less than 10% children. The rash may appear three days to a month after infection. Images of rashes are available from the Centre for Disease Control and Prevention (CDC).

Additional symptoms include:

• fatigue
• chills
• fever
• headache
• muscle and joint pain
• swollen lymph nodes

As the disease progresses, it can enter a "second stage" which can last several months. Symptoms at this stage include:

• migraines
• weakness
• multiple skin rashes
• painful or stiff joints, similar to arthritis
• abnormal heart beat
• extreme fatigue

Stage three includes chronic arthritis and neurological symptoms including headaches, dizziness, numbness and paralysis. Deaths from Lyme disease are rare but may occur.

Lyme disease can be difficult to recognize, and it has been confused with other diseases. It is important for people to consult with their doctor if they feel it is possible that they have Lyme disease.

In most cases, most often people will experience a mild illness that is sometimes accompanied by a peculiar skin rash. In some cases, however, the bacteria can spread to the joints, heart, and brain and cause serious health problems.

Pregnant women should seek medical help immediately as Lyme disease can be a health risk to the baby including still births.

Can Lyme disease be treated?

In most cases, yes. Antibiotics can effectively treat Lyme disease, especially when treatment begins early. Cases that reach the later stages of the disease, however, can be difficult to treat and may develop in to a chronic illness.

How do I know if I have a tick bite?

Many people who develop the disease do not remember seeing ticks or being bitten. Tick bites commonly occur from May to September in North America, although this varies from year to year and from region to region. Ticks sometimes move around on the body but they usually attach themselves to the skin and stay in one place. Before feeding, ticks look like small, brown scabs or freckles. After feeding, ticks may swell considerably, and could be as big as a raisin or a small grape.

For more information about ticks (including photographs), please see the Ticks and Lyme Disease document on the Public Health Agency of Canada's.

Are some locations more at risk than others?

Yes and no. There are areas in which the bacteria is endemic meaning the disease is established and present more or less continually in that community.

In Canada, these endemic areas include the north shore of Lake Erie including the Long Point area, Rondeau Provincial Park, and Turkey Point as well as the St. Lawrence Islands National Park area in Ontario. Other areas where there may be higher risk of infection include

• Ontario - Point Pelee National Park, Presqu'ile Provincial Park, Prince Edward Point National Area
• Nova Scotia - Lunenburg and Bedford areas
• Manitoba - Buffalo Point area
• British Columbia - most of the province, but largest tick populations are on the lower mainland, Vancouver Island, and Fraser Valley.

However, it is important to note that ticks (including those that are infected with the Borrelia burgdorferi bacteria) can be spread by birds, in particular songbirds that feed off the forest floor. Because these birds are migratory, there is the potential for new populations of the bacteria to spread across the country. This fact means that you do not have to be in an endemic or high-risk area to be at risk of contacting ticks and the disease.

What tests are available for Lyme disease?

When a person becomes infected, the body creates antibodies to protect itself from the bacteria. Certain blood tests are available to measure these antibodies. However, sometimes a "false negative" test can result if there are not enough antibodies in the blood for the tests to detect accurately. A doctor should also do a complete medical examination and get information about your activities in order to make a clinical diagnosis for Lyme disease.

Who is at risk?

Many occupations may be at risk, including forestry, farming, veterinarians, construction, landscaping, ground keepers, park or wildlife management, and anyone who either works outside or has contact with animals that may carry the ticks (including domestic animals like dogs, cats, goats, cows, horses, etc.)

Similarly, any person who spends a lot time outdoors (hiking, camping, birding, etc.), especially in grassy or wooded areas may also be at risk.

How can Lyme disease be prevented?

In areas where ticks are found, people should know about the risk of Lyme disease and should take precautions to protect themselves. Be aware of the signs and symptoms of Lyme disease so it can be detected and treated promptly.

• Find out from your local public health office if there are ticks in your area, especially Ixodes ticks.
• Wear protective clothing to prevent ticks from attaching to your skin. Wear long sleeve shirts that fit tightly around the wrist, and long-legged pant tucked into your socks or boots.
• Use insect repellents containing DEET to repel ticks. Apply to both clothes and skin. Always read the label and follow instructions for use.
• If possible, avoid contact with low bushes and long grasses. For example, if hiking or walking, walk in the centre of the trail.
• Wear light coloured clothing to help you to find the ticks more easily.
• Check for ticks on and under clothing, especially after being in areas where ticks may live.
• A daily skin inspection greatly reduces the risk of infection as ticks may take several hours to two days to attach to the skin and feed. Check areas including armpits, in and around hair, navel, groin, and behind the ears and knees. Also check children and pets.
• Wash clothes promptly and put them in the dryer with heat to help kill any ticks that may remain.
• Carefully remove ticks found attached to the skin. Gently use fine pointed (needle-nose) tweezers to grasp head and mouth parts of the tick as close to the skin as possible. Pull slowly to remove the whole tick. Try not to squash or crush the tick since this can help bacteria to get into the body.
  • Keep the tick for testing by placing it in a small sealed container or double zip lock bags. Place a moist paper towel or tissue with the tick to help keep it alive. Dead ticks can be tightly sealed in rubbing alcohol. Bring the tick to your doctor.
• Wash affected area with soap and water or disinfect (with alcohol or household antiseptic) after removing ticks.
• Know how to identify ticks, and know the signs and symptoms of Lyme disease.
• Contact a doctor immediately if you have an illness that resembles Lyme disease.

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Document last updated on April 15, 2008

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