Lyme Disease Fact Sheet

• What is Lyme disease?
• How do people get Lyme disease?
• What are ticks?
• What are the symptoms of Lyme disease?
• How is Lyme disease diagnosed?
• What is the treatment for Lyme disease?
• What precautions should you take to avoid Lyme disease?
• How prevalent is human Lyme disease in Canada?
• What is the Government of Canada doing to address Lyme disease?

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The Public Health Agency of Canada (PHAC) conducts surveillance for Lyme disease in Canada and studies show the risk of the disease is growing in this country. According to recent research, published in April 2010, the risk is emerging in parts of southern Quebec due to newly found populations of ticks that carry the bacterium that causes Lyme disease.

What is Lyme disease?

Lyme disease is an illness caused by the bacterium, Borrelia burgdorferi, which can be spread through the bite of certain types of ticks. Lyme disease in humans can have serious symptoms but can be effectively treated. Lyme disease has been reported in parts of Europe, Asia, and throughout much of North America.

How do people get Lyme disease?

Ticks get infected when they feed on mice, squirrels, birds and other small animals that can carry the bacterium. Ticks then spread the bacterium to humans. Two types of ticks are responsible: the western blacklegged tick in British Columbia and the blacklegged tick, sometimes called the deer tick, in other parts of Canada. People can’t spread Lyme disease to each other. Although dogs and cats can contract Lyme disease, there is no evidence that they can spread the infection to people. Pets can, however, carry infected ticks into homes and yards. Hunters may be at greater risk, because they spend more time in woodland and brush areas where ticks tend to live. However, Lyme disease cannot be contracted from eating deer.

What are ticks?

Though closely related to insects, ticks are actually a type of mite. Ticks vary in size and colour; blacklegged ticks are very small. Before feeding, adult females are approximately 3-5 mm in length and red and dark brown in colour. Ticks feed on blood by attaching to animals or people with their mouth parts. Females are a little larger than males and when they’re full of blood can be as big as a grape. Younger tick life stages are smaller and, when unfed, are lighter in colour. People and pets can pick up ticks by brushing against vegetation.

There are established populations of the tick that transmits Lyme disease in Canada. Though western blacklegged ticks are widely distributed in British Columbia, populations are largest in the lower mainland, on Vancouver Island and in the Fraser Valley. Established populations of blacklegged ticks, on the other hand, have been found in southeastern Quebec, southern and eastern Ontario, southeastern Manitoba and parts of New Brunswick and Nova Scotia.
Blacklegged ticks can be found in many areas of Canada, even where tick populations have not been identified, These ticks are introduced into these areas by migratory birds. About 10 percent of these ticks are infected with the Lyme disease bacterium. So, w hile it is possible to be bitten by an infected tick almost anywhere in Canada, the chances of this happening in places where tick populations are not established is very low.

What are the symptoms of Lyme disease?

The symptoms of Lyme disease usually happen in three stages, although not all patients have every symptom. The first sign of infection is usually a circular rash called erythema migrans or EM. This rash occurs in about 70-80  percent of infected people. It begins at the site of the tick bite after a delay of three days to one month. Other common  symptoms include

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

If untreated, the second stage of the disease can last up to several months and include

• central and peripheral nervous system disorders
• multiple skin rashes
• arthritis and arthritic symptoms
• heart palpitations
• extreme fatigue and general weakness

If the disease remains untreated, the third stage can last months to years with symptoms that can include recurring arthritis and neurological problems.

Fatalities from Lyme disease are rare.

How is Lyme disease diagnosed?

The diagnosis of Lyme disease should be made after evaluating a patient's symptoms and the risk of exposure to infected ticks. Blood tests may also be used to detect the presence of antibodies to the bacteria.

It should be stressed that the results of blood tests cannot be interpreted without information about a person’s symptoms. The Public Health Agency of Canada recommends the two-tiered approach for blood testing (screening blood samples with one test and continuing testing only on samples that test positive for Lyme disease). The Agency cautions against the use of invalidated tests or interpretation of results without appropriate guidelines. Blood tests may be negative in patients with early Lyme disease or in patients who have had antibiotic treatment. However, the accuracy of blood tests increases as the infection progresses.

What is the treatment for Lyme disease?

Several antibiotics can treat the illness. The sooner treatments starts, the better. Most cases of Lyme disease can be cured with a 2-4 week treatment of doxycycline, amoxicillin, or ceftriaxone. People with certain neurological or cardiac problems may require intravenous treatment with penicillin or ceftriaxone. Patients diagnosed in the later stages of the disease can have persistent or recurrent symptoms requiring a longer course of antibiotic treatment.

What precautions should you take to avoid Lyme disease?

In areas where ticks are found, people should know about the risk of Lyme disease and protect themselves.

• Find out from the local public health office if there are ticks, especially blacklegged ticks, in the area.
• When walking in tick-infested areas, wear clothing that will keep ticks from getting to bare skin. Wear closed shoes, long-sleeved shirts that fit tightly around the wrist and tuck them into pants. Protect your legs by tucking pants into socks or boots. Ticks show up better on light-coloured clothing.
• Insect repellents containing DEET are safe and can effectively repel ticks. Repellents can be applied to clothing as well as exposed skin but should not be applied to skin underneath clothing (note: DEET may damage some materials). Always read and follow label directions.
• Check for ticks on clothing and skin after being in tick-infested areas. A daily total-body inspection and prompt removal of attached ticks (within 18 to 24 hours) can reduce the risk of infection. Blacklegged ticks are very small, particularly the younger stages, so look carefully. Do not forget to check children and pets as well.
• Carefully remove attached ticks using tweezers. Grasp the tick's head and mouth parts as close to the skin as possible and pull slowly until the tick is removed. Do not twist or rotate the tick and try not to squash or crush the tick during removal.
• After removing ticks, wash the bite site with soap and water or disinfect it with alcohol or household antiseptic. Note the day of the tick bite and try to save the tick in an empty pill vial or doubled zip-lock bag.
• Contact a doctor immediately if you develop symptoms of Lyme disease, especially when you have been in an area where blacklegged ticks are found. If you have saved the tick, take it with you to the doctor's office.

How prevalent is human Lyme disease in Canada?

In 2010, Lyme disease became a nationally reportable disease in Canada. This means that all medical professionals must report cases of Lyme disease to the Public Health Agency of Canada (PHAC) via their provincial public health system. PHAC posts information on reportable, or notifiable, diseases on its website. PHAC surveys the provinces and territories to assess the number of cases and distribution of Lyme disease in Canada. This survey does not capture all of the cases of Lyme disease in Canada, particularly cases of early Lyme disease. Recent studies suggest that the incidence of Lyme disease in Canada is increasing.
The risk for exposure to the disease is highest in regions where the ticks that transmit Lyme disease are known to be established. These regions are parts of southern and southeastern Quebec, southern and eastern Ontario, southeastern Manitoba, New Brunswick and Nova Scotia as well as much of southern British Columbia. Surveillance data indicates a small number of blacklegged ticks are introduced into widely separated areas of Canada by migratory birds, posing some risk that individuals in other areas may also be exposed to infected ticks.

Although rarer than Lyme disease, there are other infections that can also be contracted from blacklegged ticks. These include Anaplasma phagocytophilum, the agent of human granulocytic anaplasmosis; Babesia microti, the agent of human babesiosis and Powassan encephalitis virus. The precautions outlined above will also help to protect individuals from these infections.

What is the Government of Canada doing to address Lyme disease?

The Canadian Institutes of Health Research (CIHR) is currently funding a health research project on Lyme disease. Funding of $820,000 over five years has been provided to study the properties of the tick. This health research project will lead to further understanding of the pathogen causing Lyme disease.

Public Health Agency of Canada scientists continue to collaborate in studying the occurrence of tick populations in Canada. These studies show there is low risk of encountering ticks infected with the Lyme disease agent in most of Canada although the number of risk areas is increasing in eastern Canada. Many of these findings have been published and reported at scientific meetings to help increase awareness of the potential for Lyme disease to occur in Canada.

In addition, Public Health Agency of Canada scientists are currently researching the potential impacts of climate change on the distribution of the ticks that carry Lyme disease. This research will contribute to our understanding of the occurrence of the disease.