Written by Phillip George · Last updated: January 2, 2026
This page is designed as a citation-first “data hub.” Every number below is linked to a primary source, and we separate reported surveillance counts from estimated burden to avoid confusion.
Key takeaways
- United States (reported): Over 89,000 Lyme disease cases were reported to CDC in 2023 (routine national surveillance).
- United States (estimated): CDC cites an estimate that about 476,000 people may be diagnosed and treated for Lyme disease each year (includes treatment based on clinical suspicion; may include non-Lyme cases).
- Canada (reported): PHAC reports 4,785 Lyme disease cases in 2023 and 5,239 preliminary cases in 2024.
Lyme disease — United States (CDC)
Source: CDC “Lyme Disease Surveillance and Data” (facts & stats).
| Metric | Value | Year | What it represents | Source |
|---|---|---|---|---|
| Reported Lyme disease cases (to CDC) | Over 89,000 | 2023 | Cases reported through routine national surveillance | CDC — Lyme Disease Surveillance and Data |
| Estimated diagnoses & treatment | ~476,000 | Annual estimate | Estimated people diagnosed and treated; includes some treated on clinical suspicion who may not have Lyme disease | CDC — Lyme Disease Surveillance and Data |
Lyme disease in Canada, 2009–2024 (PHAC)
Source: Public Health Agency of Canada (PHAC) “Monitoring of Lyme disease in Canada.”
Reported Lyme disease cases in Canada have climbed steeply over 15 years — from 144 in 2009 to a preliminary 5,239 in 2024, more than a 35-fold increase. Individual years bounce around (surveillance is affected by weather, testing, and reporting practices), but the long-term direction tracks the spread of blacklegged ticks into new parts of the country.
Download: Canada Lyme disease reported cases (2009–2024) CSV
This chart needs JavaScript — the same figures are in the table below.
| Year | Reported cases (Canada) |
|---|---|
| 2009 | 144 |
| 2010 | 143 |
| 2011 | 266 |
| 2012 | 338 |
| 2013 | 682 |
| 2014 | 522 |
| 2015 | 917 |
| 2016 | 992 |
| 2017 | 2,025 |
| 2018 | 1,487 |
| 2019 | 2,634 |
| 2020 | 1,617 |
| 2021 | 3,147 |
| 2022 | 2,525 |
| 2023 | 4,785 |
| 2024 (preliminary) | 5,239 |
Definitions & methodology notes
- Reported cases: Counts reported through surveillance systems (useful for trends; affected by reporting/testing/case definitions).
- Estimated diagnoses & treatment: An estimate of people diagnosed/treated; not equal to lab-confirmed surveillance totals.