TORONTO — Toronto Public Health is reporting its first laboratory-confirmed case of West Nile virus in a human in 2025.
The agency says the person is an adult and was infected in Canada.
The virus is transmitted to humans through infected mosquitoes.
The Public Health Agency of Canada’s West Nile virus surveillance report says that as of July 12, there were no cases of humans acquiring the virus within the country this year.
That means the Toronto case could be the first person infected within Canada this year. The Canadian Press has reached out to PHAC for confirmation.
PHAC’s report says two people were infected this year while travelling outside of the country.
Its surveillance map shows West Nile detections in two mosquito pools in Ontario and one in Manitoba.
Toronto Public Health says symptoms usually begin between two to 14 days after a mosquito bite and can include fever, headache, nausea, vomiting, body aches, skin rash, swollen lymph glands or a stiff neck.
It says older adults and people with compromised immune systems are at higher risk of severe illness.
People can prevent infection with the virus by avoiding mosquito bites — wearing light-coloured long sleeves and long pants, using Health Canada-approved insect repellent, getting rid of standing water in buckets, planters, pool covers and other containers to eliminate mosquito breeding grounds and putting tight-fitting screens on all windows.
This report by The Canadian Press was first published July 31, 2025.
Canadian Press health coverage receives support through a partnership with the Canadian Medical Association. CP is solely responsible for this content.
Nicole Ireland, The Canadian Press
