First West Nile Virus Positives Found in York Region Mosquito Traps
York Region Public Health has confirmed that two mosquito traps in Markham—one near Warden Avenue and Highway 7 East and another at the intersection of Kennedy Road and 16th Avenue—tested positive for West Nile virus, marking the region’s first positive mosquito findings this summer.
Halton Region Reports Its Initial Batch
Earlier in July, the Halton Region recorded its first batch of West Nile‑positive mosquitoes for the year, a development that preceded the York Region detections.
How West Nile Virus Is Transmitted
West Nile virus is spread to humans through the bite of an infected Culex mosquito. These mosquitoes thrive in urban environments where standing water collects in birdbaths, flower pots, discarded tires, old toys and other containers.
Typical Illness and Recovery
Most people infected with West Nile virus experience no symptoms. A minority develop flu‑like illness including fever, headache, body aches, joint pain, vomiting, diarrhea or a rash. The majority recover fully.
Potential for Severe Disease
Serious Health Complications
In some cases the virus can cause severe central nervous system illness such as encephalitis—inflammation of the brain—or meningitis, which is inflammation of the membranes surrounding the brain and spinal cord.
Individuals with certain underlying conditions—including cancer, diabetes, high blood pressure, kidney disease—or those over the age of 50 are at higher risk for serious outcomes.
Public Health Response and Prevention
York Region Public Health monitors mosquito populations by setting traps, applying larvicides in catch basins and other stagnant water sites, and testing mosquitoes weekly for West Nile virus. The agency also investigates reported human cases.
Residents are urged to reduce mosquito breeding around their homes by eliminating standing water, securing window screens, and covering outdoor items that can collect rainwater.
Personal protection steps include removing or emptying containers that hold water, ensuring window screens are intact and properly installed, wearing light‑colored long‑sleeved clothing, using insect repellent that contains DEET or Icaridin, and avoiding outdoor activities during dawn, dusk, and shaded wooded areas.
For more information, contact York Region Health Connection at 1‑800‑361‑5653 (TTY 711) or visit york.ca/WestNile. Additional guidance for Halton Region is available at halton.ca.
