First local case of West Nile virus reported in 2025

Waterloo Region – Public Health has confirmed the first human case of West Nile virus (WNV) for 2025 in Waterloo Region. The last local case was reported in 2024.  

"The continued warm temperatures have extended the life cycle of mosquitoes in our region and across the province," said Dr. Rabia Bana, Associate Medical Officer of Health. "As we wait for cooler fall weather and the first frost, residents should continue to take precautions to protect themselves from mosquito bites while spending time outdoors. It's also a good idea to check your property and remove any standing water where mosquitoes can breed.” 

Most people do not experience any symptoms when infected with West Nile virus. For those who do, symptoms occur 2 to 15 days following an infected mosquito bite. Symptoms may include mild fever, headache, muscle aches, stiff neck, swollen glands and skin rash. Less than one per cent of human cases develop more severe symptoms. Persons who develop symptoms of West Nile virus after getting a mosquito bite should seek medical attention. 

Protect yourself from mosquitoes  

• Use screens on your windows  
• Wear light-coloured clothing  
• Wear long sleeves, pants and a hat  
• Wear socks and closed-toe shoes  
• Use insect repellent with DEET or Icaridin according to manufacturer recommendations  
• When possible, avoid being outside at dusk and dawn when mosquitoes are most active  

Eliminate mosquito breeding grounds  

• Don’t allow outdoor objects to collect water  
• Cover rain barrels with a fine mesh screen  
• Change the water in birdbaths at least once a week  
• Keep pool covers free of standing water  
• Where possible, prevent water from collecting in ditches or in low-lying areas on your property  
• Clean up brush and debris that could act as mosquito breeding areas  
• Aerate ornamental ponds and fountains so that water does not sit still  

Public Health conducts various activities to protect residents such as case investigation, mosquito testing for WNV and larvaciding throughout the summer to control the mosquito population.   

For more information, visit: regionofwaterloo.ca/FightTheBite.  

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Media contact: media@regionofwaterloo.ca