Lyme disease is caused by a bacterium called Borrelia burgdorferi which is spread by ticks. B. burgdorferi has been found in two species of ticks in BC: Ixodes pacificus and Ixodes angustus, also known as western black-legged ticks.

Ticks are tiny bugs about the size of sesame seeds, that feed on blood. The ticks in BC prefer to get their blood meal from rodents and small animals. Sometimes a tick will bite a person accidentally instead of biting an animal. While most tick bites do not result in disease, some do.

Ixodes ticks are distributed throughout BC. However, most ticks that carry Lyme disease are found in southwestern BC, including Vancouver Island, the Gulf Islands, the Sunshine Coast, Greater Vancouver, and the Fraser Valley. The geographic distribution of Lyme disease in people and in ticks in BC has remained constant over time.

In BC, less than 1 percent of ticks tested carry the bacteria B. burgdorferi that cause Lyme disease. Although the number of ticks submitted for testing has increased in recent years, the prevalence of B. burgdorferi in ticks has remained consistently low over time. (See the chart).

Ticks live in tall grass and forested areas and attach to people or animals as they pass by. Ticks burrow part way into the skin, bite, draw blood, and then drop off. Ticks can be found year-round but they are most likely to bite in the spring (from March to June).

The risk of Lyme disease in BC is lower and more stable than it is in eastern and central Canada and in the northeastern USA. In these regions, Lyme disease rates in humans and ticks have increased with climate change. Reasons for this difference include:

• The ticks species capable of carrying Lyme disease in BC are different. I. pacificus and I. angustus (western black-legged ticks) are less capable of carrying B. burdorferi than I. scapularis (black-legged tick), the tick in eastern Canada.

• The animals on which ticks feed are different. In BC, ticks feed on small rodents such as deer mice and dusky-footed woodrat. In eastern Canada and the USA, ticks feed on white-footed mice and white-tailed deer.

• The vegetation and climate are different between BC and eastern Canada (e.g. BC has mostly coniferous forests, whereas eastern Canada has mostly leafy forests).

• Ixodes ticks are present throughout southern and central BC, including in most of the highly populated areas. An expansion of the range of these ticks, which could occur with climate change, will not greatly increase the number of people exposed in BC.

If you have the following symptoms within 3-30 days after being bitten by a tick or after having been in tall grassy or wooded areas known to have Lyme disease, consult your healthcare provider. Tell your doctor when and where you were bitten by a tick.

• Skin rash: About 70-80% of patients have a skin rash at the site of the tick bite. The rash feels warm but is not itchy or painful. It expands over a few days and can reach up to 30 cm across. Parts of the rash may clear as it enlarges, resulting in a “bull's-eye” appearance. This is called erythema migrans. Some people may not experience a rash.

• fever
• headache
• muscle and joint pains
• fatigue
• weakness or paralysis of the muscles of the face

Lyme disease is diagnosed based on symptoms, a physical exam, the possibility of exposure to infected ticks and laboratory testing. If your healthcare provider suspects Lyme disease, you may be asked to provide a blood sample for testing. Laboratory testing is not recommended for patients who do not have symptoms consistent with Lyme disease.
 

Laboratory tests support clinical care when used correctly and are performed using validated methods in an accredited laboratory. In BC, laboratory testing to diagnose Lyme disease is done by the BCCDC Public Health Laboratory (PHL), a laboratory accredited by the College of American Pathologists and the Diagnostic Accreditation Program. BCCDC PHL follows the US Centers for Disease Control & Prevention and Public Health Agency of Canada recommended process to assess for evidence of antibodies against the Lyme disease bacteria.

Blood tests may not be positive in early infection. Therefore:

• Symptoms of early Lyme disease (e.g. rash) following tick exposure may be treated by your healthcare provider on clinical grounds, even without a positive test.
• Repeat testing a few months after an initial negative test may be warranted if there are ongoing symptoms.

The great majority of people with Lyme disease can be treated successfully with 2-4 weeks of antibiotics, especially if caught early.

After months or years, people with Lyme disease who were not treated may develop complications. About 60% of untreated patients have bouts of arthritis, with severe joint pain and swelling. Large joints are most often affected, particularly the knees. Up to 5% of untreated patients develop chronic neurological complaints. These include shooting pains, numbness or tingling in the hands or feet, and problems with short-term memory.

About 10-20% of patients with Lyme disease have symptoms that last months to years after treatment with antibiotics. These symptoms can include muscle and joint pains, cognitive defects, sleep disturbance, or fatigue. The cause of these symptoms is not known, but there is no evidence that these symptoms are due to ongoing infection with B. burgdorferi. Studies have shown that continuing antibiotic therapy is not helpful and can be harmful for people suffering from these symptoms. Research to identify the reasons for such persistent symptoms should be a high priority.

If you have symptoms such as fatigue, pain, poor sleep and problems with brain function and test negative for Lyme disease, or persistent symptoms after treatment for Lyme disease, please consult the BC Women's Hospital Complex Chronic Disease Program for further support.

Certain animals, like dogs, horses and cows, can also get Lyme disease with symptoms similar to those seen in humans. Dogs are particularly susceptible. Symptoms may not appear for 7-21 days or longer after a tick bite, so watch your dog closely for changes in behaviour or appetite. Tick bites on dogs may be hard to detect. If you find a tick on your dog, remove it as you would in a human.

To reduce the chances that a tick will transmit disease to your pets:

• Check your pets for ticks after they spend time outdoors.
• If you find a tick on your dog, remove it right away.
• Ask your veterinarian to conduct a tick check at each exam.
• Talk to your veterinarian about tickborne diseases in your area.
• Talk with your veterinarian about using tick preventives on your pet.

There is only a very small chance of ticks transmitting Lyme disease to humans. However, the disease can be serious, so it is worth taking steps to avoid being bitten.
To protect yourself against tick and insect bites:

• Walk on cleared trails wherever possible when walking in tall grassy areas, or forested areas.
• Wear light coloured clothing so you can see ticks, tuck your top into your pants and tuck your pants into your boots or socks.
• Put insect repellent containing DEET or Icaridin on all uncovered skin and clothing. Reapply as frequently as directed on the container.
• When leaving an area where ticks may be found:
• Take a bath or shower to remove loosely attached ticks
• Check your entire body for attached ticks including the scalp, folds of skin, under the arms, behind the knees. Have someone help you check hard-to-see areas.
• If a tick is found, remove it immediately (see below for instructions).
• Check children, pets and outdoor gear for ticks.
• Put clothing in a hot dryer for 10 minutes to kill any remaining ticks.

The most important thing is to make sure that you remove all the tick, including the mouth parts that maybe buried in your skin. Also, do not squeeze the body of the tick when you are removing it. This can force its stomach contents into the wound and increase the chance of infection. If you find a tick:

• remove the tick yourself;
• get someone else to remove the tick for you (when you can't reach it or see it clearly); or
• get your healthcare provider to remove it.

How NOT to remove a tick!

Some people think you can remove a tick by covering it with grease, gasoline or some other substance. This does not work! It only increases the chance of you getting an infection. Holding something hot (for example, a match or cigarette) against the tick also does NOT work! Again, this will only increase the chance of an infection or accidentally burning yourself.

If you decide to remove the tick yourself, follow the instructions below.

When should you remove the tick?

You should only remove the tick yourself, or get a friend or family member to remove it, if the tick is not buried very deep into your skin. The feeding tick's mouth will be under the skin, but the back parts will be sticking out. If the tick has been on your skin for less than two hours, it has probably not had a chance to burrow into your skin. If the tick is just on the surface of your skin, or only biting on to the outside skin layer, you can remove it following the instructions below.

When should you get a doctor to remove the tick?

You should go to your doctor to get the tick removed if it has buried itself deep into your skin. This usually happens if the tick has been on you for several hours, or even a day or two. When a tick has burrowed deep into your skin, it is very hard to remove the tick without leaving some mouth parts behind, which can cause infection.

How to remove a tick

Remove the tick right away (if possible, wear disposable gloves when handling an engorged tick):

• Use tweezers or forceps to gently get hold of the tick as close to the skin as possible. Don't touch the tick with your hands.
• Without squeezing the tick, steadily lift it straight off the skin. Avoid jerking it out. Try to make sure that all of the tick is removed.
• Once the tick has been removed, clean the bite area with soap and water, then disinfect the wound with antiseptic cream.
• Wash your hands with soap and water.

How to submit a tick for testing

Ticks found on BC residents can be tested for free at the BCCDC Public Health Laboratory if submitted by a physician.  Commercial tick tests are not recommended. If your doctor wants to have the tick tested:

• Save the tick in a container with a tight fitting top.
• Dampen a small cotton ball and put it into the tick container to keep the tick alive.
• An intact dead tick may also be identified and tested for Lyme disease by PCR.
• Note the geographic coordinates or location and date the tick was found or bite occurred.
• Your physician should use the Parasitology requisition, indicate the source of the tick (e.g. human, pet, other), the geographic coordinates or location the tick was found and the name and address of the person bitten. Label the container with two matching identifiers to the requisition.
• Ticks must be submitted as soon as possible by a physician or public health professional to:

BCCDC Public Health Laboratory

Parasitology

655 West 12th Ave.

Vancouver V5Z 4R4 BC Canada

Ticks found on BC animals can also be tested at the BCCDC Public Health Laboratory. Veterinarians will be charged $65 per tick for tick identification and PCR testing for Lyme disease if it is not a human- related tick. If no Lyme disease carrying tick is identified, there is a $30 charge for tick identification only.