OPH confirms first human case of West Nile virus in city this year

Ottawa Public Health (OPH) has confirmed the presence of West Nile virus in local mosquitoes, as well as the first human case in the city in 2024.

OPH has been monitoring mosquitoes for the virus since June 1.

In a press release Friday evening, the agency confirmed that it had detected both the first positive cases in mosquitoes and the first human infection of the year.

The virus currently poses a “moderate to high” risk to public safety, said Alison Samuel, OPH health inspector, in an interview on Saturday.

The infected person has now recovered, Samuel added.

No confirmed cases in Ottawa last year

In 2023, there were no confirmed cases of West Nile virus in Ottawa, although there were 54 confirmed cases across Ontario.

The West Nile virus is mainly transmitted by the northern house mosquito. Culex spp. Only a few people are bitten by a mosquito that carries the virus.

However, about 20 percent of those infected may experience flu-like symptoms such as fever, headache, muscle aches and rash.

Less than one percent of infections result in severe illness, with the virus potentially affecting the central nervous system. The risk of severe illness increases with age and is also higher in people with weakened immune systems, according to the OPH.

OPH urges citizens to take precautions against mosquito bites and prevent mosquito reproduction by following the following measures:

• Apply a Health Canada-approved mosquito repellent containing DEET or icaridin to skin and clothing.

• Protect yourself between dusk and dawn, when mosquitoes are most active, and in shady, bushy or wooded areas.

• Wear light-colored, tightly woven, loose-fitting clothing, including long pants, long-sleeved shirts, shoes and socks.

• Make sure all windows and doors have fly screens in good condition.

• Remove standing water around your home weekly, including birdbaths, toys, flowerpot saucers, pool covers, old tires, wheelbarrows, buckets and cans.

• Make sure that all openings of the rain barrel are always covered with a sieve.

The City of Ottawa has also implemented a plan that includes weekly monitoring and mosquito larvicidal treatment at locations on city property where water accumulates, OPH said.