Lyme Disease

Key Messages

The prevalence in Ottawa of Borrelia burgdorferi (the agent of Lyme disease) in local Ixodes scapularis (the blacklegged tick vector) meets the threshold for Ottawa Public Health (OPH) to recommend the consideration of post-exposure prophylaxis for persons on whom a blacklegged tick was feeding if ALL of the following criteria are met:

  • the tick is fully or partially engorged or has been attached for 24 or more hours and
  • it has been less than or equal to 72 hours since the tick has been removed and
  • doxycycline is not contraindicated (e.g., pregnancy).

Individuals who do not meet all of the above criteria for post-exposure prophylaxis should be counselled on the signs and symptoms of early Lyme disease and should be monitored for 32 days for an expanding skin lesion at the site of the tick bite (erythema migrans) or systemic symptoms and signs of an infectious illness with or without fever.

Suspected and/or confirmed cases of Lyme disease, whether clinically diagnosed or laboratory confirmed, are reportable to local public health under the Health Protection and Promotion Act. This includes individuals who have been clinically diagnosed with Lyme disease in the absence of serology.

Introduction

Lyme disease is an infection caused by Borrelia burgdorferi, a bacteria transmitted through the bite of an infected blacklegged tick (Ixodes scapularis). Most humans are infected through the bite of an immature tick (nymph) during the spring, summer and fall months.

Risk of transmission of Borrelia burgdorferi from tick to human increases with the duration of tick attachment. When ticks acquired in high-risk areas have been attached less than approximately 24 hours, the probability of infection is low enough not to warrant use of prophylaxis. Nevertheless, in this situation patients should be counselled to observe for rash—especially an expanding red rash at the site of the initial tick bite—or other symptoms of Lyme disease for 32 days, and return for medical assessment should these arise. Partial or full engorgement of nymph and adult ticks would suggest the tick has been feeding longer than 24 hours, and should trigger the recommendation for prophylaxis for those eligible. The general principles of antibiotic stewardship should be applied and an informed consent discussion should include the risks of antibiotic therapy to the individual.

Blacklegged ticks in various stages of feeding:

Three nymphs of the blacklegged tick are shown in different stages of feeding.

Tick nymphs

The following image shows 5 female blacklegged ticks in different stages of feeding.

5 female blacklegged ticks in different stages of feeding

For additional photos showing blacklegged ticks in various phases of engorgement from feeding visit the Tick Encounter Resource Center website.

Local Epidemiology

Blacklegged ticks are present in Ottawa and transmission of Lyme disease from infected ticks is known to occur here. Regions surrounding Ottawa, including many locations where Ottawa residents visit for recreation, may also be considered risk areas for Lyme disease. Visit the Public Health Ontario (PHO) website to view the Ontario Lyme disease risk maps (published annually).

Information regarding both number of cases and incidence of Lyme disease in Ottawa can be found on the 
Reportable Infectious Diseases Statistics page.

Signs and Symptoms 

Diagnosis of early localized Lyme disease is based solely on clinical presentation and history of potential exposure. Patients may not recall a tick bite because nymphs can be the size of poppy seeds and difficult to see, so an assessment of likelihood of exposure to blacklegged ticks is an essential part of the risk assessment.

Please report all suspect and clinical diagnoses of Lyme disease to OPH, not only those confirmed by laboratory testing.

Early localized disease : (3 to 32 days following tick bite)

A classic sign is erythema migrans, a single expanding red rash with clearing behind the outer ring ("bull's eye") and usually greater than 5 cm in diameter. However, the appearance of the rash may vary (e.g., there may not be any central clearing) and it is not present in approximately 20 to 30% of cases. Other symptoms can include fatigue, fever, headache, lymphadenopathy, myalgia and arthralgia. Note: a small area of erythema at the site of the tick bite may appear within the first 48 hours of a bite, but may reflect local irritation rather than early Lyme disease.

The Government of Canada website has more images of rashes post exposure.

Early disseminated disease: (days to weeks following tick bite, less than 3 months)

If untreated, the infection can spread via the bloodstream and cause additional erythema migrans rashes on other areas of the body, fatigue, weakness, neurologic symptoms (e.g., facial nerve palsy, meningitis, encephalopathy) and/or cardiac symptoms (carditis, conduction abnormalities).

Late disseminated disease: (months to years following tick bite)

If untreated, about 60% of patients may develop arthritis (chronic or intermittent, often affecting the knees) and up to 5% may have neurologic symptoms (problems with memory and concentration, paresthesias).

Post-treatment Lyme disease syndrome

Approximately 10 to 20% of patients may have lingering fatigue, pain, joint and muscle aches, sleep disturbance or cognitive difficulties following appropriate antibiotic treatment. The cause of these symptoms is not known. Treatment with extended courses of antibiotics has not proven effective for post-treatment Lyme disease syndrome and carries risk of serious complications.

Diagnosis/Laboratory Testing 

In most cases, the visual identification of erythema migrans can be sufficient to diagnose a patient with Lyme disease who has been bitten by a tick from an area known to have ticks that carry Borrelia burgdorferi. Delaying antibiotic treatment for Lyme disease while awaiting results of laboratory serology testing in these circumstances is not recommended, nor is laboratory testing of ticks.*  In the absence of erythema migrans, clinical diagnosis may be more difficult and consideration should be given to serologic testing of the patient not only at the time of the first visit, but again at least 2 weeks later. In the first 2 weeks of infection, serologic sensitivity is low; therefore, a convalescent sample 2 to 4 weeks after the first test will improve test sensitivity. Each of these tests is conducted at the PHO laboratory as two-tier testing (i.e., ELISA screening, if reactive or indeterminate, is followed by Western blot confirmation).

Serologic testing is also useful for patients in whom early disseminated or late Lyme disease is suspected.

A downloadable requisition form is available from the Public Health Ontario Laboratory's website (English only).

If the tick bite occurred in Europe, please provide a specific travel history on the lab requisition form, as the specimen will be forwarded to the National Microbiology Laboratory for appropriate testing.

Private laboratory testing for Lyme disease is not recommended. These laboratories often use unvalidated tests and/or interpretation criteria – treatment decisions should not be based on these tests.

*Turn-around times for tick identification (3 or more weeks) and testing (up to 6 or more months) are too long to be useful in the patient’s management. Ticks sent to the Public Health Ontario Lab are identified and may be sent to the National Microbiology Laboratory for testing for B. burgdorferi. For more information see “Tick Identification and Testing” under “Laboratory” at PHO’s Lyme Disease web page.

Reporting Requirements 

All cases of Lyme disease, whether clinically diagnosed or laboratory confirmed, are reportable to local public health under the Health Protection and Promotion Act. Note: This includes individuals who have been clinically diagnosed with Lyme disease in the absence of serology. Public Health is mandated to collect information on clinical signs and symptoms (such as diameter of any erythema migrans), as well as information on tick exposure.

Health Care Provider Lyme Disease Reporting Form [PDF 170 KB]

Management 

Antibiotic treatment of Lyme disease:

For drugs, dosages, and duration of treatment therapy, please consult a reference such as the American Academy of Pediatrics 2018 Red Book or one of the on-line references listed in the Physician Resources section below.

In early localized disease or early disseminated disease with isolated facial nerve palsy, the treatment of choice is oral doxycycline for patients of any age. However, doxycycline has not been adequately studied in pregnancy, and consideration should be given to the alternatives, amoxicillin or cefuroxime.

Short-term use of doxycycline is considered acceptable in breastfeeding mothers. More information can be obtained from LactMed (English only), or Motherisk (English only).

Early disseminated Lyme disease with meningitis or cardiac symptoms or late disseminated Lyme disease may also be treated with oral antibiotic agents, including doxycycline. The longer duration of treatment of late disseminated disease means that children younger than 8 years should receive an antibiotic other than doxycycline. The American Academy of Pediatrics states in its 2018 Red Book that there “are limited safety data on the use of doxycycline for >21 days in children <8 years if age.” Consider consultation with an infectious disease specialist in the event of disseminated Lyme disease.

Chemoprophylaxis following a tick bite:

A single dose of oral doxycycline may be offered to adult patients (200 mg dose) and to children of any age (4.4 mg/kg, up to a maximum dose of 200 mg), when all of the following conditions are met:

  • patient presents with an engorged or partially engorged blacklegged tick or history of one that was attached for more than 24 hours
  • exposure in known risk area
  • it has been less than 72 hours since removal of the tick
  • doxycycline is not otherwise contraindicated

Doxycycline is relatively contraindicated for pregnant women. In cases of pregnancy, the patient and her provider should make an informed choice between a single dose of doxycycline and no prophylaxis with close observation for Lyme disease signs and symptoms for 32 days.

Short-term use of doxycycline is considered acceptable in breastfeeding mothers. More information can be obtained from LactMed (English only), or Motherisk (English only).

When a patient has been exposed to ticks in other health units:

Public Health Ontario has a risk area map that indicates places in which chemoprophylaxis should be considered after tick bites: Ontario Lyme Disease Map 2018 - Estimated Risk Areas [PDF].

Please visit specific health units' websites for the current recommendations for exposure to ticks in their respective health units. A listing of Ontario public health units can be found at the Ministry of Health and Long-Term Care website.

The Institut national de santé publique Québec (INSPQ) publishes a risk area map for Québec at https://www.inspq.qc.ca/zoonoses/maladie-de-lyme.

Health Canada has a risk area map for Canada at https://www.canada.ca/en/public-health/services/diseases/lyme-disease/risk-lyme-disease.html.

If a patient presents with the tick attached:

  1. Use tweezers to grasp the tick where it attaches to the skin.
  2. Pull the tick straight out, slowly and firmly, and do not jerk or twist the tick as this can cause the tick's mouthparts to break off. Avoid squeezing the tick's abdomen.
  3. Disinfect the feeding site after the tick is removed.

Tick removal diagram

4. Tick identification:

a) Lab turn-around times for tick identification (3 or more weeks) and testing (up to 6 or more months) are too long to be useful in the patient’s management. If you do decide to submit the tick, place it in a sterile container and submit it to the Public Health Ontario Laboratory. Ticks sent to the Public Health Ontario Lab are identified and may be sent to the National Microbiology Laboratory for testing for Borrelia burgdorferi. For more information see “Tick Identification and Testing” under “Laboratory” at PHO’s Lyme Disease web page.

b) Use Bishop’s University electronic tick identification platform (eTick, https://www.etick.ca/): anyone can submit a picture of a tick and receive species identification results within 48 hours, along with public health education and awareness messaging.

c) Try to identify the tick yourself using the ID guide and chart at the University of Rhode Island’s TickEncounter Resource Center (https://tickencounter.org/).

Prevention
Prevention of tick bites is a cornerstone of Lyme disease prevention. Patients are advised to adopt the following practices:
  • Application of a Health Canada approved insect repellent containing DEET or icaridin to exposed skin and clothing
  • Wearing long pants, a long sleeved shirt, shoes and socks to cover exposed skin
  • Tucking pants into socks
  • Wearing light coloured clothing so it is easier to spot ticks
  • If possible, staying on the trails when hiking in the woods or walking in long grass
  • Performing a "full body" check (also on children, and pets if applicable) for ticks. Ticks often attach in areas such as between toes, behind knees, in the groin, armpits and scalp.
Public Health Role 

All cases of Lyme disease, whether clinically diagnosed or laboratory confirmed, are reportable to local public health under the Health Protection and Promotion Act. Note: This includes individuals who have been clinically diagnosed with Lyme disease in the absence of serology. Public Health is mandated to collect information on clinical signs and symptoms (such as diameter of any erythema migrans), as well as information on tick exposure.

Health Care Provider Lyme Disease Reporting Form [PDF 170 KB]

Patient Information 
Information for the public can be found on the Lyme Disease page (Printable PDF) and the Healthy Canadians website.
Physician Resources 

Canada

US

Contact Us

If you have questions regarding Lyme disease, or want to notify Ottawa Public Health about a case of Lyme disease, please contact us at 613-580-2424, ext. 24224.

Health Care Provider Lyme Disease Reporting Form [PDF 170 KB]

Contact Us