West Nile virus detected in Ottawa mosquitoes

(File image. Source: Center for Disease Control and Prevention / James Gathany)

The city of Ottawa says recent testing has confirmed the presence of West Nile virus (WNV) in the local mosquito population.

"Three mosquito testing pools indicate WNV is present in Ottawa; these are the first positive testing pools since the annual monitoring season began June 1, 2023," the city said in a news release Monday.

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This result comes a couple of weeks earlier than last year, when the first positive tests were reported in September.

To date, there are no confirmed or probable cases of West Nile virus in Ottawa residents, but Ottawa Public Health is reminding people to be cautious.

"Mosquitoes can pose a risk for WNV infection until the first hard frosts of the fall. Residents are reminded that even in late summer, there remains an increased risk for human WNV infection," the city says.

The northern house mosquito is the primary way West Nile virus spreads. Most people will not experience symptoms if infected, but in a small number of cases, it can cause serious illness. About 20 per cent of people who contract the virus might experience flu-like symptoms, including fever, headache, muscle aches and, possibly, a rash. The risk of more serious illness that affects the central nervous system increases with age. This type of serious illness occurs in less than one per cent of infections, OPH says.

You can protect yourself and your family from mosquito bites by:

• Applying a Health Canada-approved mosquito repellent containing DEET or icaridin to exposed skin and to clothing;
• Protecting yourself especially between dusk and dawn, when mosquitoes are most active, and at all times in or near shady, bushy, or wooded areas;
• Wearing light-coloured, tightly woven, loose-fitting clothing, including long pants, a long-sleeved shirt, shoes and socks to protect exposed skin;
• Making sure all windows and doors in your home have well-fitting screens that are in good condition;
• Reducing standing water sites around your home, such as bird baths, toys, flowerpot saucers, swimming pool covers, old tires, wheelbarrows, buckets, and cans – anything that can hold water for seven days or longer;
• Keeping all openings to rain barrels covered with screen mesh at all times.