Government of New Brunswick

Health professionals are encouraged to further their knowledge of Lyme disease in Canada. This includes information on:

Take precautions against ticks if you are working in, living in, or visiting areas with blacklegged ticks.

Although it is possible to be bitten by an infected tick anywhere in New Brunswick, the risk is highest areas where blacklegged tick populations are established or appear to be established.  Higher Risk Areas are defined on a county level because it is difficult to define the geographic limits of tick populations and blacklegged ticks have been spreading in New Brunswick.

The following is a map of the estimated areas of risk based on provincial tick surveillance data and reports of human disease.  Counties in the Higher Risk Area with established blacklegged tick populations include:

  • Charlotte County
  • Saint John County
  • Kings County
  • Albert County
  • Westmorland County


New Brunswick Lyme disease Risk Areas
Figure 1: Risk areas of established or emerging black tick populations in New Brunswick.

Lyme disease is a serious illness caused by the bacterium Borrelia burgdorferi. The bacterium is a spirochete transmitted by certain species of Ixodes ticks. In eastern Canada it is spread through the bite of infected blacklegged ticks (Ixodes scapularis). Blacklegged ticks can transmit other pathogens, for example anaplamosis, babesiosis and Powassan fever.


Patients may have no or minimal symptoms but most cases present as one of three stages, which may occur in overlapping stages :

  • Early localized disease
  • Early disseminated disease
  • Late disseminated disease

Early localized disease (less than 30 days*) usually presents as an acute illness characterized by systemic manifestations - fever, arthralgias, headache and skin manifestations - a single, localized skin lesion known as erythema migrans (EM).  Most patients will present with EMs within 7 days of the initial tick bite; however, the incubation period can vary between 3 and 30 days.  The skin lesion is present in approximately 80% of patients.  EM is a characteristically annular erythematous lesion greater than 5 cm in diameter that slowly increases in size.  The lesion sometimes develops a central clearing but can be homogenously erythematous.  It is usually painless and non-pruritic. 

Early disseminated disease (less than 3 months*) can develop if untreated, as the bacterium disseminates via the bloodstream to other body sites and provokes damage to body tissues at those sites.  Systemic manifestations include fever, arthralgias, headache, and lymphadenopathy.  Skin manifestations include multiple EM lesions).  Heart manifestations include atrioventricular block, tachyarrhythmias, myopericarditis, and myocardial dysfunction.  Central nervous system manifestations include aseptic meningitis, cranial neuropathy (especially facial nerve palsy), and motor or sensory radiculoneuropathy.  Other manifestations including conjunctivitis can also occur.

Late disseminated disease (more than 3 months*) can last months or even years if it remains untreated.  Musculoskeletal manifestations include oligoarticular arthritis.  Central nervous system manifestations include encephalopathy, axonal polyradiculoneuropathy, and chronic encephalomyelitis.  Occular manifestations include retinitis.

* Note these time frames provide a general guide, there may be exceptions.

Some people treated for Lyme disease continue to have symptoms months to years after treatment.  This condition is known as post-treatment Lyme disease syndrome (PTLDS). The exact case of PTLDS is not yet known.  Most medical experts believe that the lingering symptoms are the result of damage to tissues and the immune system that occurred during the infection.  Studies are ongoing to determine the cause of PTLDS.  If you have been treated for Lyme disease and still feel unwell, see your doctor to discuss how to relieve your suffering and help you cope with your symtpoms using the best tools available.  This includes maintaing a healthy diet, getting plenty of rest, and exercise regularly.  Find support from family, friends and others who can help you find ways of and managing your life and dealing with ongoing symptoms.  Patients with PTLDS almost always get better with time; however,it can take months to feel completely well.  


If a patient presents with a tick is still attached, appropriate removal involves the use of a blunt, medium-tipped, angled forceps, and the bite area should be inspected carefully for any retained mouthparts, which should be excised. Patients with tick bites of concern should be monitored closely for manifestations of early localized disease, for up to 30 days.  Note an erythematous skin lesion present while a tick vector is still attached or which has developed within 48 hours of detachment is most likely a tick bite hypersensitivity reaction. Hypersensitivity reactions are usually < 5 cm in largest diameter, sometimes have an urticarial appearance, and typically begin to disappear within 24–48 hours.

Early localized Lyme disease (erythema migrans) does not require diagnostic testing before treatment is started.  A presumptive diagnosis can be made on the basis of the clinical presentation, seasonal occurrence and a history of exposure to infected black legged ticks. 

Diagnostic testing is appropriate for persons with symptoms of early localized Lyme disease (erythema migrans) that occurs out of season or no known history of exposure to infected blacklegged ticks, for example exposure in a risk or endemic area.

Diagnostic testing is also appropriate for persons with characteristic neurological, cardiac of joint involvement.

The two-tiered serological testing approach is an appropriate tool and includes an enzyme immunoassay (EIA) screening test and a confirmatory Western blot test (if the EIA is positive or equivocal).

For erythema migrans (acute phase) without an exposure in an endemic areas testing by the 2 tiered serology (repeat EIA in four weeks if negative) is recommended and treatment at physicians discretion.

Canadian laboratory diagnostic guidelines for Lyme disease are consistent with those followed by public health authorities in the United States and Europe and meet international standards.  Public health professionals in these countries have ongoing concerns regarding American for-profit laboratories that may not be using properly validated tests or criteria for interpreting test results.  By using unvalidated methods, patients who don’t have Lyme disease may test positive and they may end up receive potentially harmful treatments.

Can individuals be re-infected with Borrelia burgdorferi?

Re-infection is the recurrence of symptoms as a result of a new exposure to an infected tick, leading to a new infection.  Re-infection can occur in as many as 2%-21% of patients living in endemic areas who have had Lyme disease. On examination, re-infection typically presents with an erythema migrans lesion at a different site than the original lesion more than 1-2.5 years after the original infection and not within 11 months of the first infection.

Laboratory diagnosis of re-infection becomes a challenge, given that serology, including lgM, can remain positive for many years. Diagnosis is reliant on the clinical presentation of a new erythema migrans lesion at a different site.


Laboratory confirmed and suspect clinical cases of Lyme disease are reportable to Public Health as per regulation (in writing within seven days). 


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Lindsay LR, Bernat K, Dibernardo A.  Laboratory Diagnosis for Lyme Disease.  Canada Communicable Disease Report.  May 2014;40-11:209-217.

Wormser GP, Dattwyler RJ, Shapiro ED, Halperin JJ, Steere AC, Klempner MS, Krause PJ, Bakken JS, Strle F, Stanek G, Bockenstedt L, Fish D, Dumler S, Nadelman RB.  The Clinical Assessment, Treatment and Prevention of Lyme Disease, Human Granulocytic Anaplasmosis, and Babesiosis: Clinical Practice Guidelines by the Infections Diseases Society of America.  Clinical Infectious Diseases 2006; 43: 1089-134.

The laboratory diagnosis of Lyme borreliosis: Guidelines from the Canadian Public Health Laboratory Network. Can J Infect Dis Med Microbiol 2007; 18(2): 145-8.