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Lyme disease

Deer ticks cause Lyme disease Deer ticks cause Lyme disease  

What is Lyme disease?

Lyme disease is a bacterial infection transmitted by the blacklegged tick, also known as the deer tick. The infection is caused by the bacterium Borrelia burgdorferi, which is spread through tick bites.

When treated early with the appropriate medications, children can recover completely from deer tick bites. However, if it is undiagnosed or untreated, Lyme disease can lead to serious recurring or long-term health problems.

Lyme disease is often called “the great imitator” because it can look like different diseases or neurological disorders. Lyme disease is often misdiagnosed as a number of other conditions and illnesses, for example multiple sclerosis, Parkinson’s disease, autism​ or schizophrenia.

Signs and symptoms of Lyme disease

Symptoms of Lyme disease may occur in three stages. Not all children infected by Lyme disease go through these stages.

Stage 1 Lyme disease

For most people, the first sign of infection may be a circular rash at the site of the tick bite. The rash can appear from a day to a month after a tick bite. The most common sites for a rash are the thigh, groin and armpit.​

When the rash starts, it is usually flat, but it can sometimes be slightly raised. Patients often describe the skin as burning or occasionally painful or itchy. Over time, the redness becomes wider, measuring anything from 1 cm to 30 cm (1/2 to 12 inches) across. It may look like a bull’s eye, with a red ring surrounding a clear area and a red centre.

The rash usually fades after three to four& weeks, but it can persist for over a year. It is often accompanied by the following symptoms:

Stage 2 Lyme disease

Left untreated, Lyme disease can spread in the body over the following days and weeks and progress to a second stage. The symptoms of stage 2 Lyme disease may include:

  • nervous system disorders
  • multiple skin rashes
  • arthritis and arthritic symptoms
  • heart palpitations (occasional skipped and/or faster heartbeats)
  • extreme fatigue and general weakness.

Stage 3 Lyme disease

If Lyme disease is still left untreated, it can progress to the third stage over the following months or years. The symptoms of stage 3 Lyme disease can last for months or years and may include:

  • chronic arthritis
  • neurological problems like meningitis or Bell's palsy​
  • numbness or weakness in the arms and legs
  • impaired muscle movement
  • memory loss
  • difficulty concentrating
  • changes in mood or sleep habits.

Children who are treated with antibiotics in the first or second stage of Lyme disease almost never develop third-stage disease.

How ticks spread Lyme disease

The bacteria that cause Lyme disease are usually carried in squirrels, mice, birds and other small animals. Blacklegged ticks (deer ticks) spread Lyme disease to humans by feeding on infected animals and then feeding on people. The tick must be attached to the skin for at least two days to transmit the Lyme bacteria.

How to identify a deer tick

Deer ticks are usually red or dark brown and can be 3 to 5 mm (1/8 to 1/4 inch) long. After feeding on an animal or human, the tick can swell to the size of a grape.

How ticks are transported

Ticks travel from southern regions on the wings of migrating birds. Household pets, like cats and dogs, may also transport ticks on their fur into your home.​ Ticks can also be found in forest bushes and overgrown areas between the woods and open spaces.

Ticks attach to a person by their mouth when that person’s bare skin brushes up against long grasses or bushes or comes in contact with surfaces (such as animal fur) where ticks are already present.

Where deer ticks are most common

Deer ticks are found in Europe, Asia and many parts of North America. In Canada, the western blacklegged tick can be found in British Columbia’s lower mainland, on Vancouver Island and in British Columbia's Fraser Valley. The blacklegged tick has been found in southern and eastern Ontario, southeastern Manitoba and parts of Nova Scotia. Because the tick is carried on migrating birds, it can also be found in other locations.

Risk factors for Lyme disease

If your child plays in a tick-infested forest or in grassy fields, they will be at a greater risk for Lyme disease. Since ticks attach easily to bare skin, having exposed skin is also a risk factor.

If a tick attaches to your child’s skin, it is important to remove the tick as soon as possible. Removing ticks with a tweezers within 24 to 36 hours usually prevents infection.​

Complications of Lyme disease

Lyme disease in pregnant women has been associated with stillbirths.

How a doctor can help your child with Lyme disease

Lyme disease is not always easy to diagnose because its symptoms can resemble those of other diseases. In addition, not everyone who gets a tick bite develops a rash.

Your child’s doctor will evaluate your child’s symptoms and may order a blood test if they suspect Lyme disease. Blood test results can be negative or positive. A negative result means that no antibodies to the bacteria causing Lyme disease have been found in the blood.

If your child gets a negative result to a blood test that is done when symptoms first appear, it does not always mean that they are free of Lyme disease. Blood tests become more reliable as the condition progresses. If the first blood tests are negative, repeat blood tests are recommended several weeks later to test for any antibodies.

Treatment of Lyme disease

It is important to treat Lyme disease very quickly so that your child's condition does not get worse. ​If your child is diagnosed with Lyme disease, the doctor will likely prescribe antibiotics.

Most children will recover after two to four weeks of antibiotic treatment. If your child’s Lyme disease has had a chance to progress, they may need to take antibiotics for longer. If your child has other symptoms, like neurological disorders, they may require other medications.

Preventing Lyme disease

If your child plans to play in tick-infested grasses or fields, there are some ways that you can reduce their exposure to ticks.

  • Apply insect repellent on exposed skin.
  • Wear long pants, closed-toe shoes (no sandals) and socks to protect bare skin from ticks.
  • Wear light-coloured clothing so ticks are easier to spot.
  • Avoid areas where there are many insects.
  • Wear clothing treated with insecticide.
  • Check for ticks on clothing and skin after playing or hiking in tick-infested areas.

If you find a tick on your child's skin, carefully remove it with tweezers. Do not squash or crush the tick while it is attached to the skin, as this can increase the chance of spreading infection. You can save the tick in a plastic bag to show to a doctor later.

Be careful with DEET insect repellent

DEET-based insect repellents work very well against ticks, but a high concentration of DEET can be harmful to your child. Make sure that your child’s insect repellent is specially formulated for children and contains 10% DEET or less. Natural insect repellents, such as citronella, also work but may need to be re-applied more frequently.

Key points

  • Lyme disease is a bacterial infection transmitted by the deer tick.
  • The first sign of infection is usually a circular red rash at the location of the tick bite, which then spreads in a “bulls eye” pattern. Not everyone with Lyme disease has this rash.
  • If your child is diagnosed with Lyme disease, the doctor will prescribe antibiotics.
  • To help prevent tick bites and Lyme disease, keep skin covered, apply insect repellent to your child’s skin and check for ticks on clothing and skin after playing or hiking in tick-infested areas.
​Jonathan Gubbay, MBBS, MSc, FRCPC

​Further information

Centers for Disease Control and Prevention (US) Lyme Disease

Public Health Agency of Canada. Canada Communicable Disease Report CCDR:​ Lyme Disease​Volume 40-5, March 6, 2014. Ottawa, ON: Government of Canada.