West Nile virus found in Manitoba mosquitoes
A mosquito is sorted according to species and gender before testing for West Nile Virus at the Dallas County mosquito lab in Dallas on May 11, 2007. (LM Otero/AP)
Published Sunday, July 31, 2016 5:23PM EDT
The Manitoba government has discovered mosquitoes infected with West Nile virus in three rural municipalities in the southern part of the province. No human cases have yet to be reported.
The mosquitoes were collected during the week of July 20 in traps placed in Altona, West St. Paul and Winkler. While several mosquito species were found, Culex tarsalis mosquitoes – one of the primary vectors for West Nile virus – were present in increasingly significant numbers. These are the first infected mosquitoes discovered in the province this year.
West Nile virus is a mosquito-borne illness that can cause encephalitis or swelling of the brain. While some people show no signs of infection, mild symptoms such as headache, fever, fatigue and body aches are common. Severe illness occurs mostly in older adults or people with compromised immune systems. Long-term complications such as coma, paralysis and even death can happen in the most severe cases.
First identified in Uganda in 1937, the virus has been present in North America since at least 1999.
Southern Manitobans are at particular risk of exposure between June and September, especially during sustained warm and dry conditions. According to Manitoba Health, Seniors and Active Living, you can reduce the risk of exposure to West Nile virus by:
- Limiting the time spent outdoors during dawn and dusk.
- Using mosquito repellant.
- Wearing light-coloured and loose-fitting clothing.
- Making sure door and window screens fit and are free of holes.
To reduce the number of Culex tarsalis mosquitoes around their homes, Manitobans are also being urged to eliminate standing water by:
- Cleaning eavestroughs and making sure items like bird baths and old tires are free of water.
- Making sure rain barrels are covered with mosquito screening or are tightly sealed around the downspout.
- Enhancing landscaping to limit standing water.
Despite the discovery of infected mosquitoes, there are currently no orders for adult mosquito control in the province. The province also offers a cost-shared larvicide program with Manitoban communities. 53 communities are currently participating in the program.