Ontario Vector-Borne Disease Tool

The Ontario Vector-borne Disease Tool offers comprehensive surveillance data on vector-borne diseases (VBDs) in Ontario. This interactive resource allows users to explore trends in human cases for anaplasmosis, babesiosis, Lyme disease, Powassan virus infection, and West Nile virus illness, as well as surveillance data for mosquitoes and ticks, and blacklegged tick established risk areas. VBD data are available across multiple dimensions, including year-to-date and weekly case counts, mosquito and tick species distribution, and positive surveillance results.

This tool is updated weekly for all human VBD cases, and annually for all tick data. Mosquito data will be updated weekly during the mosquito season (May–October).

Updates as of May 4, 2026:

• New Ticks Tab: A new tab showing passive tick submissions from healthcare providers and the public, represented by Aggregate Dissemination Area census boundaries, using data from PHO’s Laboratory Information Management System (LIMS) and supplemented with eTick data
• 2026 Blacklegged Tick Risk Area Map: Reflecting newly identified or expanded tick risk areas based on 2025 data
• 2025 Season Updates: Updated with new data released since the last surveillance season, including finalized 2025 human case and vector data
• New 2026 Data and In-Season Reporting: New 2026 layers to support weekly updates as data become available during the upcoming season

Historical West Nile virus data can be provided upon request. Visit PHO’s Data Requests page for more information.