Lyme Disease Underreported in Canada: Study Suggests Major Gap
Cases may be far higher than reported
Testing limitations play a role
Diagnosis is often missed
Public health impact is underestimated
Lyme disease may be significantly underreported in Canada. A study suggests that the true number of cases could be many times higher than official reports—raising concerns about missed diagnoses and gaps in public health response.
The authors estimate that under-detection in Canada may exceed the commonly cited 10-fold underreporting seen in the United States.
How Much Is Lyme Disease Underreported?
In one region:
- Actual cases may be underestimated by 12.1- to 58.2-fold
- Only 1.7% to 8.3% of cases may be detected
This suggests a substantial gap between reported and true disease burden.
For more on testing limitations, see Lyme test accuracy.
Estimated True Case Numbers
In 2016:
- 992 cases were officially reported in Canada
- Estimated true cases ranged from 8,432 to 56,147
The difference reflects widespread under-detection.
Why Lyme Disease Is Missed
The authors identified several contributing factors:
- Failure to report clinically diagnosed cases
- Missed recognition of early Lyme disease
- Failure to include Lyme disease in differential diagnosis
- Limited use of serologic testing in later stages
- Insensitivity of two-tier testing algorithms
Testing limitations and clinical awareness both contribute to underdiagnosis.
For more, see Lyme disease misdiagnosis.
Testing Limitations Play a Major Role
The authors estimate:
For every reported case of Lyme disease, up to 30 additional cases may be missed due to testing insensitivity.
This raises important questions about reliance on standard testing alone.
For more, see Can you have Lyme disease with a negative test?
Public Health Implications
Underreporting affects more than statistics.
The authors warn that underestimation may lead to:
- Inadequate healthcare resource allocation
- Reduced research funding
- Delayed recognition of expanding disease risk
The true burden of Lyme disease may be significantly underestimated.
Impact on Patients
Beyond public health, underdiagnosis has real consequences:
- Delayed treatment
- Persistent symptoms
- Reduced quality of life
- Loss of function and productivity
For more, see:
Clinical Takeaway
Lyme disease underreporting in Canada may be substantial—driven by testing limitations and missed diagnoses.
Clinicians should consider Lyme disease even when testing is inconclusive.
Improved awareness and diagnostic strategies are essential to better capture the true burden of disease.
Related Reading
Reference
- Lloyd VK, Hawkins RG. Healthcare (Basel). 2018.
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
