June 30, 2023
West Nile Virus Bulletin #1
Manitoba Health reports that Culex tarsalis mosquitoes carrying the West Nile virus (WNV) were collected from the Rural Municipality of West St. Paul during the week of June 18 to 24. This is the first mosquito pool that has tested positive in Manitoba this season.
The first positive pool was detected earlier than normal this year, likely due to warmer temperatures in southern Manitoba this spring and summer. There have only been three other times in the last 20 years where a positive mosquito pool was detected during this week.
The risk of WNV infection depends on various factors including time of year, number and location of infected Culex tarsalis mosquitoes, and the number of days with sufficient heat. Risk of exposure to WNV is currently low but likely to increase in the coming weeks, as the highest risk period is historically in July and August. Manitobans are reminded that it takes just a single bite from an infected mosquito to contract WNV.
While most people who are infected will develop mild or no symptoms, some can develop severe symptoms that can result in hospital stays and even death. Recovery from WNV infection, particularly severe symptoms, can take months or years.
While Manitobans are encouraged to enjoy outdoor activities, it is critical to reduce the risk of mosquito bites and potential exposure to WNV by:
- reducing the amount of time spent outdoors during peak mosquito hours between dusk and dawn;
- using an appropriate mosquito repellent;
- wearing light-coloured, loose-fitting clothing with long sleeves and pant legs;
- maintaining door and window screens; and
- cleaning and emptying yard items that collect water.
In 2022, there were seven cases of WNV in Manitoba, and five of those were hospitalized. No confirmed human cases of WNV have been identified in Manitoba yet this year.
WNV updates will continue to be shared with the public throughout the summer.
For more information about prevention, symptoms, weekly average trap counts of Culex tarsalis mosquitoes, fact sheets, posters and information for municipalities and health-care providers, visit www.gov.mb.ca/health/wnv/.
Manitobans can also contact Health Links-Info Santé at 204-788-8200 or at 1-888-315-9257 (toll-free) for more information.
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