News Releases

The Office of the Chief Medical Officer of Health advises that since last week, three additional positive test result of West Nile virus have been reported in Manitoba.  

 

The numbers of Culex tarsalis mosquitoes identified in southern Manitoba for the week of July 1 remain higher than usual for this time of year. New orders are being issued for adult mosquito control in three communities.

 

To date, a total of six positive test results of West Nile virus have been reported in Manitoba.  Two test results were identified through Canadian Blood Services routine screening and the donated units were discarded according to plan.  Four test results were identified through clinical testing.  

 

Additional information on these cases including age, gender, regional health authority of residence and likeliest area of exposure will be provided on the website when it becomes available at http://www.gov.mb.ca/health/wnv.

 

As of today, new orders under Manitoba’s Environment Act are being issued to control adult mosquitoes in Boissevain, Deloraine and Killarney.  Adult mosquito control based on orders issued previously in Altona, Beausejour, Brandon, Carman, Headingley, Morden, Niverville, Oakbank, Stonewall, West St. Paul, Winkler and Winnipeg. The need for ongoing mosquito control in these communities is under continuous evaluation.  

 

Mosquito samples from three other communities across southern Manitoba from the week of July 1 were identified as positive for West Nile virus.  These communities are Carberry, Souris and St. Andrews.  Adult mosquito control has not been recommended in these communities at this time.

 

Information on adult mosquito control schedules for West Nile virus and a description of the areas to be sprayed is available on the Manitoba Health website at http://www.gov.mb.ca/health/wnv as it becomes available.

  

The Chief Medical Officer of Health reminds Manitobans that they 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 also reduce mosquito numbers near their homes and in their communities by reducing standing water. To reduce the development of Culex tarsalis mosquitoes: 

·         clean eavestroughs;

·         at least once a week, empty bird baths and other items that might collect water;

·         cover rain barrels with mosquito screening or maintain tight seals around downspouts; and

·         dispose of old tires or other debris that collect water.

 

Culex tarsalis mosquitoes are the mosquitoes in Manitoba most likely to carry the West Nile virus.  These mosquitoes have been found in increasing numbers over the past several weeks in a number of communities in southern Manitoba.

 

To date in 2007, West Nile virus infected mosquitoes have been found in the communities of Altona, Beausejour, Boissevain, Brandon, Carberry, Carman, Deloraine, Headingley, Killarney, Morden, Niverville, Oakbank, Roblin, Sioux Valley, Souris, St. Andrews, Steinbach, Stonewall, Stony Mountain, Virden, West St. Paul, Winkler and Winnipeg. The province continues to monitor adult Culex tarsalis mosquito numbers in these communities and others across southern Manitoba.

 

The number of cases of the more severe type of West Nile virus (neurologic illness) in previous years has ranged from one to 35 severe cases per summer. In previous years, the last three weeks of July and the first three weeks of August have been the period of highest risk of human exposure to West Nile virus in Manitoba.

 

Health Canada has concluded the use of malathion for adult mosquito control in residential areas using ultra-low-volume application will not pose a health concern.  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,