2012 West Nile Virus update – 04
Manitoba Health advises the most recent surveillance information on Culex tarsalis mosquito numbers and the proportion infected with West Nile virus has reached a level warranting a new order under Manitoba’s Environment Act for adult mosquito control in the City of Portage la Prairie including an extended treatment area three km around the city.
The community has a high level of infected mosquitoes that may pose a risk to human health.
Health Canada has concluded the use of malathion for adult mosquito control in residential areas using an ultra-low-volume application will not pose a health risk. However, people who wish to further reduce their exposure to malathion can take additional precautions including:
• closing all doors and windows,
• avoiding trucks while spraying is underway,
• turning off fans and air conditioners or setting them at exhaust,
• removing clothes and children’s toys from outdoor areas,
• rinsing any household items or toys left outside before using them, and
• washing fruits and vegetables.
Recent hot, humid conditions have created ideal conditions for the development of Culex tarsalis mosquitoes, biting activity and the transmission of West Nile virus. Manitoba Health is reporting a high risk of exposure to West Nile virus (WNV) throughout southern Manitoba and Manitobans are urged to take special care to reduce the risk of mosquito bites and WNV, even when there do not appear to be many mosquitoes.
To date, two Manitobans from the Winnipeg Health Region have tested positive for West Nile virus through Canadian Blood Services screening. Initial reports indicate that one of the individuals reported mild symptoms and the other had no symptoms. The investigation continues as to when and where the exposures to the WNV may have taken place.
So far in 2012, 48 mosquito samples tested positive for West Nile virus have been identified from
17 communities across southern Manitoba.
Manitoba Health will continue to monitor the situation on an ongoing basis.
To reduce the risk of mosquito bites and West Nile virus, Manitobans are encouraged to:
• reduce the amount of time spent outdoors during peak mosquito hours between dusk and dawn;
• use appropriate mosquito repellent;
• wear light-coloured, loose-fitting clothing; and
• maintain door and window screens so they fit tightly and are free of holes.
Manitobans can also reduce the number of mosquitoes around their home by eliminating standing water. To reduce standing water:
• 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.
Manitobans can check the West Nile virus website regularly for up-to-date data and information, including weekly average trap counts of Culex tarsalis mosquitoes by regional health authority.
For more information about West Nile virus, contact Health Links-Info Santé at 204-788-8200 or 1-888-315-9257 (toll-free); or visit the province’s WNV website at www.gov.mb.ca/health/wnv.