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Lyme Disease

 

Epidemiology

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 B.C.: Ixodes. pacificus and Ixodes angustus. These are different from the ticks that carry Lyme disease in eastern Canada and the USA. I. pacificus and I. angustus are less capable of carrying B. burdorferi than I. scapularis, the tick in eastern Canada and the USA.


The ticks that spread Lyme disease are tiny bugs , about the size of a sesame seed, and they feed on blood. Different ticks prefer different types of animals. The Ixodes ticks in BC tend to bite rodents and small animals. Sometimes a tick will bite a person instead of biting an animal. While most tick bites do not result in disease, some do.

Ixodes ticks can be found throughout BC. However, most ticks found to carry B. burgdorferi are found in southern BC, including Vancouver Island, the Lower Mainland, the Sunshine Coast, the Fraser Valley and the Kootenays.  In BC, less than 1 percent of ticks tested carry the bacteria that cause Lyme disease. The prevalence of B. burgdorferi in ticks in BC has remained constant over time and consistently low between 1996 and 2014. The geographic distribution of human Lyme disease and B. burgdorferi in ticks in BC has also remained constant during this time period.  

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.

Ticks live in tall grass and wooded areas and attach to people or animals as they pass by. Ticks burrow part way into the skin, bite, draw blood, then drop off. They are easiest to spot when they are actually sucking blood. The feeding tick's mouth will be under the skin, but the back parts will be sticking out. They will be full of blood and blue-grey in colour (this is called an "engorged" tick).
 

Symptoms

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 doctor or other healthcare provider. Tell your doctor when and where you were bitten by a tick.

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

Diagnosis

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 BC Public Health Microbiology and Reference Laboratory (BC PHMRL), a laboratory accredited by the College of American Pathologists (CAP) and the Diagnostic Accreditation Program (DAP). BC PHMRL 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 based on antibodies may not be positive in early infection.  There are two important implications: 
  • Symptoms of early Lyme disease (e.g. rash as above) following tick exposure may be treated by your doctor on clinical grounds, even without a positive test.
  • Repeat testing a few months after an initial negative test may be wise if there are ongoing symptoms.

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

 

Treatment

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

Complications

After months or years, people with Lyme disease who were not treated may develop complications. About 60% of untreated patients have intermittent 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.
 

Lyme disease in pets

Certain animals, like dogs, horses and cows, can also get Lyme disease with symptoms similar to those seen 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 behavior 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.
 

Prevention

To protect yourself against tick and insect bites:

  • Walk on cleared trails wherever possible when walking in tall grass or woods.
  • Wear light coloured clothing, tuck your top into your pants and tuck your pants into your boots or socks.
  • Put insect repellent containing DEET on all uncovered skin. Reapply as frequently as directed on the container.
  • Check clothing and scalp (covered or not) when leaving an area where ticks may live.
  • Check in folds of skin. Have someone help you check hard-to-see areas. When a tick is located, remove it immediately. Check the whole body! Don't stop when you find one tick. There may be more. Make sure the lighting is good so that you will not miss seeing the ticks.
  • Regularly check household pets for ticks.

Tick removal and testing

  The most important thing is to make sure that you remove all the tick, including the mouth parts that are 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 have found a tick, you have three choices:

  • remove the tick yourself;
  • get someone else to remove the tick for you. (This is when you can't reach it or see it clearly, for example if it's on your scalp, or some other hard-to-reach place); or
  • get your family doctor 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. 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

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. (A live tick is necessary for culturing the spirochete which causes Lyme disease.)
  • Label the container with date shipped, name and address of person bitten or what type of animal the tick was from, what part of the body was bitten, and what part of the province the tick probably came from. Also include the name and address of your physician.
  • Testing is only available for BC residents.
  • Ticks must be submitted as soon as possible by a physician or public health professional to:

BC Public Health Microbiology and Reference Laboratory
Parasitology
655 West 12th Ave.
Vancouver V5Z 4R4 BC Canada

Last Updated: June 11, 2015