Certain species of mosquitoes are the main carriers of West Nile virus.

West Nile virus threat fizzles out

Metro scraps coordinating role, cities still free to control nuisance mosquitoes

Despite years of predictions that mosquito-borne West Nile virus would arrive in the Lower Mainland, the potentially deadly illness is still a no-show here.

And Metro Vancouver has now decided to stop spending $76,000 a year coordinating a regional response to the threat.

Nobody has ever been infected by West Nile within the Lower Mainland and it’s only been detected here once – in a horse in Aldergrove in 2009.

The B.C. Centre for Disease Control now considers Metro Vancouver to be at the very edge of the potential reach of the virus, which has infected people in the Interior and Washington State.

The virus had spread rapidly across North America in the early 2000s but activity in the Pacific Northwest has since slowed considerably.

Fraser Health said this year it no longer recommends preemptive use of larvicide to control mosquitoes in its region and provincial funding for West Nile response that used to be administered through a Metro function has been cut off.

The Fraser and Vancouver Coastal health authorities will instead work directly with local municipalities to direct West Nile mosquito control and prevention if and when the virus poses a more serious risk in this area.

Metro Vancouver will still control nuisance mosquitoes on its own lands, such as Metro regional parks, as will some cities, including Richmond.

Fraser Health has also scaled back its program to monitor mosquitoes, crows and ravens that serve as indicator species for West Nile.

There were 24 probable or confirmed West Nile cases in B.C. residents from 2007 to 2010, but nearly all of them are believed to have been contracted travelling elsewhere.

There have been no cases anywhere in B.C. in the last two years.

About 20 per cent of West Nile-infected people get a fever and other symptoms, recovering within a week or so. About one in 150 get severe illness, such as brain inflammation or polio-like paralysis that can be fatal.

Authorities had repeatedly urged residents to use insect repellent during mosquito season and to take other preventative measures, such as clearing stagnant water from properties.