Toronto Public Health (TPH) has reported its first probable human case of West Nile virus (WNV) in an adult resident in 2023. WNV is an infection transmitted to people through the bite of an infected mosquito.
While the risk of getting infected in Toronto is currently low, TPH encourages residents ahead of the August long weekend to take the following precautions to avoid bites from infected mosquitos:
WNV symptoms usually start to show between two and 14 days after a person is bitten by an infected mosquito. Symptoms may include fever, headache, nausea, vomiting, body aches, skin rash and swollen lymph glands. Older individuals or people with compromised immune systems are at higher risk of severe illness. Anyone concerned about any symptoms should contact their health care provider.
TPH conducts mosquito surveillance and monitoring from mid-June until mid-September every year. Once a week, 22 mosquito traps are set across Toronto to collect mosquitos which are then submitted to a laboratory for identification and grouped by the lab into batches of mosquitos to test for WNV. So far in 2023, 20 batches – also known as pools – of mosquitos have been found to be positive for WNV. With the increased hot weather in Toronto lately, there is a higher risk of mosquitos that can transmit the virus once they are infected. In 2022, a total of 14 batches of mosquitos were confirmed as positive for the virus, in addition to 14 laboratory-confirmed human cases of WNV.
More information about WNV and ways to reduce the risk of being infected with WNV is available on the City’s West Nile virus webpage.
“While the risk of being infected with West Nile virus remains low in Toronto, now is a good time to remind residents ahead of the long weekend of the steps they can take to avoid bites from infected mosquitos when enjoying the beautiful summer weather. Apply insect repellent, wear light-coloured clothing, long pants, long-sleeved shirts and take extra care between dusk and dawn, which are peak mosquito-biting hours.”
– Dr. Eileen de Villa, Medical Officer of Health
Toronto is home to more than three million people whose diversity and experiences make this great city Canada’s leading economic engine and one of the world’s most diverse and livable cities. As the fourth largest city in North America, Toronto is a global leader in technology, finance, film, music, culture and innovation and climate action, and consistently places at the top of international rankings due to investments championed by its government, residents and businesses. For more information visit the City’s website or follow us on Twitter, Instagram or Facebook.
Toronto Public Health