Borrelia miyamotoi in Canada: 10% Infection Rate Raises Coinfection Concerns
Borrelia miyamotoi Canada cases may be more common than previously recognized.
In a study from Manitoba, Kadkhoda and colleagues tested blood samples from 250 individuals with suspected or confirmed Lyme disease. Samples were collected between 2011 and 2014.
The results were notable: 10% of participants were seropositive for B. miyamotoi—substantially higher than the 3.9% rate reported in healthy individuals from endemic regions in the northeastern United States.
This higher prevalence may reflect recent tick exposure in the Canadian cohort, compared with the healthier U.S. population.
Coinfection with Lyme Disease
Patients with Lyme disease were significantly more likely to also test positive for B. miyamotoi.
“Participants who were seropositive for B. burgdorferi were significantly more likely to be B. miyamotoi seropositive (20.3% vs. 6.6%),” the authors report (odds ratio 3.6).
This finding reinforces the clinical importance of coinfections in tick-borne illness.
Clinicians should consider B. miyamotoi in patients presenting with febrile illness without erythema migrans, particularly if symptoms are recurrent.
Why Borrelia miyamotoi Matters in Canada
Several key findings support increased awareness of B. miyamotoi:
- Seroprevalence may be comparable to babesiosis and anaplasmosis
- The organism has been identified in I. scapularis ticks across nearly all Canadian provinces
- Human cases are likely wherever Lyme disease is endemic
- Severe complications, including meningoencephalitis, have been reported
- Hospitalization is required in a subset of cases
- Transmission through blood transfusion is biologically plausible
Challenges in Testing
Diagnosing B. miyamotoi remains difficult.
Testing options include:
- PCR testing (available through reference laboratories)
- Blood smear (limited sensitivity)
- Serologic testing using ELISA followed by GlpQ Western blot
However, serologic testing is not widely available, limiting routine diagnosis.
This gap highlights a broader issue: patients with tick exposure and compatible symptoms may test negative despite active infection.
Treatment Considerations
Although this study did not evaluate treatment outcomes, the authors recommend managing B. miyamotoi similarly to Lyme disease.
Doxycycline is commonly used, though treatment should be individualized based on clinical presentation.
Clinical Perspective
This study challenges the assumption that B. miyamotoi is rare in North America.
A 10% seroprevalence in patients with suspected Lyme disease suggests coinfection may be underrecognized.
In clinical practice, patients presenting with febrile illness, especially without a rash, should prompt consideration of relapsing fever Borrelia species.
Clinical Takeaway
Borrelia miyamotoi infection may be more common in Canada than previously recognized. Coinfection with Lyme disease is frequent, and testing limitations may lead to underdiagnosis.
Clinicians should include B. miyamotoi in the differential diagnosis of tick-exposed patients with febrile illness—even in the absence of a rash.
Dr. Daniel Cameron, MD, MPH
Lyme disease clinician with over 30 years of experience and past president of ILADS.
Symptoms • Testing • Coinfections • Recovery • Pediatric • Prevention
