Hamilton confirms first West Nile virus case of the season, raising risk to high. Residents urged to use bug spray and remove standing water.
Hamilton Confirms First Human West Nile Case of 2025
Health Officials Confirm Case
Hamilton Public Health has reported the first human case of West Nile virus this season, prompting an immediate change in the city’s risk level from moderate to high. The confirmation came in a release issued on Monday, August 18, 2025, marking a significant development in the city’s annual monitoring of mosquito-borne illnesses.
Public Advisory to Residents
The city is urging residents to take protective measures against mosquito bites. Officials recommend using insect repellents containing DEET or Icaridin, wearing long sleeves and light-coloured clothing, and avoiding outdoor areas such as gardens, wooded trails, and golf courses, particularly at dawn and dusk.
Citywide Mosquito Control Efforts
In response, Hamilton is completing its third round of larvicide treatments in street catch basins and applying treatments in surface waters on public land. These measures are intended to reduce mosquito populations and limit the spread of the virus.
Why the Risk Matters
While 80% of infected individuals show no symptoms, those who do may experience fever, body aches, and fatigue within two to 14 days of a mosquito bite. More serious complications, including encephalitis or meningitis, occur in about 1% of cases, mainly among older adults or people with weakened immune systems.
Seasonal Decline Expected
Associate Medical Officer of Health Dr. Bart Harvey noted that the risk will ease following the city’s first heavy frost, which significantly reduces mosquito activity. Until then, residents are encouraged to remain cautious and take preventive steps both at home and outdoors.