BARA Bugle (Broadmead Area Residents Association Newsletter),
Spring 2005 – Diane Mothersill
As a functioning ecosystem, Rithet’s Bog contains a wide variety of natural mosquito predators. These include dragonflies, Pacific Tree Frogs, bats and four species of swallow (Barn, Violet-Green, Tree, and Northern Rough-winged). As the restored wetlands reach ecological equilibrium, it is expected these predators will respond to the increased numbers of mosquitoes and keep them in check.
To encourage natural mosquito control, Ducks Unlimited and the Rithet’s Bog Conservation Society installed swallow nest boxes in the spring of 2004. The boxes are located along the central drainage ditch and at the perimeter of the bog forest, away from the habitat of unwanted competing species such as Starlings and House Sparrows, so are not easily visible. This spring more pole-mounted boxes will be installed in appropriate locations.
Saanich is continuing to monitor the mosquito population, in terms of health effects, at Rithet’s Bog, other wetland areas in the municipality, and at several man-made reservoirs.
To read the complete article, the above excerpts are taken from the District of Saanich Summer 2004 issue of “Our Backyard”.
It is important to realize that there have been no human infections by West Nile Virus in BC. The most cases have occurred in Ontario, with a few in Quebec, Manitoba, Saskatchewan, and 1 in Alberta for a total of 25 reported cases across Canada as of December 2004. Of these, only 7 in Ontario and 2 in Quebec had confirmed West Nile neurological syndrome. To date, the virus has been detected in dead birds and mosquitoes in every province except BC, and in neighbouring states.
For information about the risks of exposure to West Nile Virus and how to protect yourself go to the Municipality of Saanich web site http://www.saanich.ca/resident/environment/westnile.html
The risk posed by this virus to healthy people is low. However, residents living adjacent to the bog and bog walkers should take appropriate control measures such as applying repellent containing DEET, staying indoors around dusk, and wearing light-coloured clothing.
The northern house mosquito (Culex pipiens) is the most common mosquito in urban and suburban areas of British Columbia and is the most likely vector of West Nile Virus in North America, both from birds to birds and from birds to people. C. pipiens is extremely lethargic and does not fly far from where it breeds. If people want to feel safe in their backyards, they need to clean out all sources of standing stagnant water, especially in eaves and downspouts. If C. pipiens mosquitoes are found in Greater Victoria’s backyards, they are breeding in the backyards. They have not flown from the bog.
Travellers to other parts of North America, Europe and Africa should be aware of the precautions necessary for their individual health and safety in areas away from home. It is good sense to practise mosquito control measures to prevent infection by WNV and other blood-borne diseases spread by mosquitoes.
Other useful web sites:
For residents who want to inform themselves further, the Vancouver Island Health Authority (VIHA) provides a list of resources to locate the most current information about the virus, its vectors, its control, personal pesticide use, and implications for human health at
http://www.viha.ca/mho/disease/west_nile_virus.htm
http://www.bccdc.org/ for B.C.
http://www.phac-aspc.gc.ca/wnv-vwn/index.html for Canada
http://www.cdc.gov/ncidod/dvbid/westnile/index.htm The U.S. Centers for Disease Control and Prevention
How to Avoid Mosquito Bites:
- Apply insect repellents containing DEET (N, N-diethyl-meta-toluamide) to exposed skin when you go outdoors. Even a short time can be long enough to get a mosquito bite.
- When possible, wear long-sleeves, long pants and socks when outdoors. Mosquitoes may bite through thin clothing, so spraying clothes with repellent containing permethrin or DEET will give extra protection. Don’t apply repellents containing permethrin directly to skin. Do not spray repellent containing DEET on the skin under your clothing.
- Dusk to dawn is peak mosquito biting time. Take extra care to use repellent and protective clothing during evening and early morning or avoid outdoor activities during these times.
Adapted from the U.S. Centers for Disease Control and Prevention web site.