Manitoba Health and Healthy Living reports that preliminary analysis of the adult mosquitoes trapped for the week of July 26 shows the numbers of Culex tarsalis mosquitoes are increasing in some communities in southern Manitoba, particularly in the southern portion of the Assiniboine Regional Health Authority. However, overall numbers remain relatively low in southern Manitoba compared to previous years.
No mosquitoes infected with West Nile virus have been identified in 2009, but it is possible that some are present in southern Manitoba at this time. Culex tarsalis mosquitoes are the mosquitoes most likely to carry West Nile virus.
Most of the mosquitoes collected continue to be nuisance mosquitoes, which do not carry West Nile virus.
In previous years, the peak risk periods for human exposure to West Nile virus have been the last two weeks of July to the first two to three weeks of August. With warm weather, it is likely the risk of West Nile virus exposure could rise during this time.
To date, no human cases of West Nile virus have been identified in Manitoba in the 2009 season.
Manitobans can reduce the risk of mosquito bites by:
• reducing the amount of time spent outdoors during peak mosquito hours between dusk and dawn;
• using appropriate mosquito repellent;
• wearing light-coloured, loose-fitting clothing; and
• maintaining door and window screens so they fit tightly and are free of holes.
Manitobans can reduce mosquitoes around their homes by reducing standing water. To prevent the development of Culex tarsalis mosquitoes, homeowners can:
• clean eavestroughs and regularly empty bird baths and other items that might collect water,
• ensure rain barrels are covered with mosquito screening or are tightly sealed around the downspout,
• clear yards of old tires or other items that collect water, and
• improve landscaping to prevent standing water around the home
