York Region reports first human case of West Nile virus

August 08, 2025

Newmarket – York Region Public Health received laboratory confirmation that an individual in the City of Vaughan has tested positive for West Nile virus (WNv), marking York Region’s first human case of 2025.

West Nile virus is a virus that is spread to humans from the bite of an infected mosquito. Most people infected with WNv will not have symptoms, but some will experience flu-like illness. In rare cases, West Nile virus can be life threatening. The risk of developing serious illness is higher in older adults and individuals with a weakened immune system.

York Region encourages residents to follow these simple Fight the Bite tips to reduce their chance of being bitten by mosquitoes:

  • Use Health Canada-approved insect repellent containing DEET or icaridin – check label directions for use
  • Wear light coloured protective clothing, including pants and long-sleeved shirts, when spending time outdoors
  • Clean or remove standing water sources, including bird baths, empty containers, swimming pool covers, outdoor toys and flowerpots

York Region’s annual West Nile virus control plan includes:

  • Mosquito control – Mosquito populations are reduced through a process called larviciding, using provincially and federally approved pesticides
  • Mosquito surveillance – Each week between June and October, up to 40 mosquito traps are set up across the Region, capturing and testing mosquitoes for the virus; York Region reported the first positive mosquito trap of 2025 on July 17, in the City of Vaughan

People who develop West Nile virus illness may experience symptoms which include fever, muscle weakness, stiff neck, confusion, severe headaches and a sudden sensitivity to light. In rare cases, the virus can cause serious neurological illness, including encephalitis, or inflammation of the brain. Older adults and individuals with a weakened immune system are at higher risk of becoming seriously ill from West Nile virus infection. Residents who experience any of these symptoms are advised to seek medical attention.

For more information on West Nile virus, visit york.ca/WestNile or contact York Region Health Connection at 1-800-361-5653 or dial 711 with a TTY device.

The Regional Municipality of York consists of nine local cities and towns and provides a variety of programs and services to 1.29 million residents and 57,000 businesses with approximately 624,000 employees. More information about York Region’s key service areas is available at york.ca/RegionalServices

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Media Contact:

Hayden Casey, Communications Associate, Community and Health Services,
The Regional Municipality of York

Phone: 905-716-1893 Email: @email
After Hours: 905-806-1216, @email