Unwelcome carrion

West Nile virus, which killed seven people when it struck New York a year
ago, has now made its way to Canada, health officials say. A dead crow found at
Canada’s southernmost city, Windsor, is the country’s first confirmed carrier.
The virus is harboured by birds and transmitted by mosquitoes. The Ontario
ministry of health will now be analysing mosquitoes and dead birds across the
province, but has not committed itself to further action. The neighbouring
province of Quebec has raised the unpopular possibility of aerial fumigation to
suppress mosquitoes.