The City of Winnipeg began fogging several neighbourhoods on Friday night, July 31, 2026 [1], to control mosquitoes carrying the West Nile virus.
The emergency measure follows a province-mandated public health response triggered by a rapid increase in virus-carrying insects. This action aims to reduce the risk of human transmission in densely populated areas during a period of high viral activity.
According to reports, the population of mosquitoes carrying the West Nile virus doubled within one week [2]. This sharp rise was detected through mosquito traps, prompting the Province of Manitoba to order the City of Winnipeg to execute the fogging program [3].
The operations began on the night of July 31, 2026 [1]. The city continued the fogging process through Saturday night, August 1, 2026 [2], targeting specific neighbourhoods where the risk was deemed highest.
Public health officials said these fogging treatments knock down the adult mosquito population quickly. While larval control is often used throughout the season, adulticide fogging is typically reserved for when viral counts reach critical thresholds [3].
Residents in the affected areas are advised to follow local health guidelines to prevent bites. These measures include wearing long sleeves, and removing standing water from properties to eliminate breeding grounds.
“The population of mosquitoes carrying the West Nile virus doubled within a single week.”
The rapid doubling of the virus-carrying mosquito population indicates a high-risk window for West Nile virus transmission. By deploying adulticide fogging, health authorities are attempting to break the cycle of transmission between mosquitoes and humans before the virus can spread further into the general population.
