Manitoba Health reports five mosquito samples tested positive for West Nile virus during the week of Aug. 15 to 21. These samples were collected in Carberry, Boissevain, Brandon, Altona and Morden. So far this year, a total of 19 positive mosquito samples have been found. Based on the current level of infected mosquitoes in these communities, adult mosquito control is not being recommended at this time.
The number of adult Culex tarsalis mosquitoes trapped during the week of Aug. 15 decreased compared to the previous week. Preliminary numbers for the week of Aug. 22 show about the same number of mosquitoes in traps as last week.
The number of trapped Culex tarsalis mosquitoes remains relatively high overall, but the proportion of trapped mosquitoes that have tested positive for West Nile virus is relatively low compared to previous years.
Although the period of highest risk for human exposure has ended, there is still a risk for human exposure. The risk is expected to decline in the weeks ahead. In previous years, the peak risk period for human exposure to West Nile virus has been the last two weeks of July and the first three weeks of August.
To date, no human cases of West Nile virus have been identified in Manitoba in the 2010 season.
Manitobans are reminded they can reduce their risk for West Nile Virus 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 the number of 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.
Information on the risk of West Nile virus will continue to be provided to the public throughout the summer in a media campaign and at various fairs and festivals. Manitobans can also check the West Nile virus website regularly for up-to-date data and information.
For more information about West Nile virus, contact Health Links–Info Santé at 788-8200 or toll-free at 1-888-315-9257. Trap count information is updated weekly and available on the Manitoba Health website at www.gov.mb.ca/health/wnv.