Vector-Borne Disease - Statistics and Trends
The following is a summary from the Vector-Borne Disease Team's seasonal highlights.
Mosquitoes
| Year | # of West Nile Virus Positive Traps | # of West Nile Virus Human Cases | # of Mosquito Treatments | # of Catch Basins Completed |
|---|---|---|---|---|
|
2025 |
0 | 0 | 235 | 31,437 |
|
2024 |
9 |
3 |
946 | 116,556 |
|
2023 |
9 |
2 |
711 | 113,780 |
- There have been 0 reported human cases of Eastern Equine Encephalitis Virus (EEEV) in Middlesex-London.
Ticks Submitted to the Middlesex-London Health Unit
| Total | 44 | 58 | 46 | 16 | 33 | 13 | 3 | 11 | 2 |
| # of Non-Vector Ticks Submitted | # of Blacklegged Ticks Acquired Within Middlesex-London | # of Blacklegged Ticks Acquired Outside of Middlesex-London | |||||||
|---|---|---|---|---|---|---|---|---|---|
| 2023 | 2024 | 2025 | 2023 | 2024 | 2025 | 2023 | 2024 | 2025 | |
|
January |
0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |
| February | 0 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |
| March | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 0 |
| April | 2 | 5 | 3 | 0 | 5 | 2 | 0 | 2 | 0 |
| May | 18 | 28 | 25 | 9 | 7 | 7 | 0 | 4 | 1 |
| June | 11 | 13 | 18 | 2 | 1 | 3 | 1 | 0 | 0 |
| July | 9 | 12 | 0 | 1 | 0 | 0 | 0 | 2 | 1 |
| August | 4 | 0 | 0 | 3 | 0 | 0 | |||
| September | 0 | 0 | 0 | 0 | 0 | 0 | |||
| October | 0 | 0 | 0 | 6 | 1 | 3 | |||
| November | 0 | 0 | 2 | 11 | 1 | 0 | |||
| December | 0 | 0 | 1 | 0 | 0 | 0 | |||
In the case of Lyme disease, a 'vector' is the term used to describe a tick species that can transmit (pass) Lyme disease through a bite. Blacklegged ticks are capable of transmitting Lyme Disease in Ontario. Other 'non-vector' ticks cannot transmit Lyme disease. View the Lyme Disease web page for more information.
Active Tick Surveillance in Middlesex-London
| Year | Number of Blacklegged Ticks Found Tick Dragging |
| 2025 | 21 |
| 2024 | 59 |
| 2023 | 58 |
Lyme Disease Cases in Middlesex-London
| Year | Number of Confirmed/Probable Human Lyme Disease Cases in Middlesex-London Residents |
| 2025 | 6 |
| 2024 | 19 |
| 2023 | 24 |
Vector-Borne Disease Surveillance Information
- For provincial information on surveillance, visit Public Health Ontario’s West Nile Virus or Lyme Disease web pages.
- For national information on surveillance, visit the Government of Canada's West Nile Virus or Lyme Disease web pages.
Additional Information
For more information about the Vector-Borne Disease Team or information about Vector-Borne Diseases and human health, please continue to browse our website, or call the Health Unit at 519-663-5317.
Date of creation: April 18, 2018
Last modified on: July 7, 2025
Last modified on: July 7, 2025