The outbreak of bird flu in British Columbia, Canada has edged closer to the border with the US, prompting the US government to send a team of veterinarians to Washington state to monitor the situation.

"The last confirmed case was a quarter mile from the US-Canadian border," Kate Sandboe, a spokeswoman for the Washington state Department of Agriculture, was quoted by the Canadian Press as saying. 

A spokesman for the Canadian Food Inspection Agency was unable to confirm immediately whether the virus had been detected so close to the border.

The agency recently said bird flu had been detected so far on 37 commercial poultry farms in British Columbia since the outbreak began in February.

Officials have ordered the slaughter of around 19 million chickens, turkeys and other birds in Fraser Valley, which is at the centre of the outbreak, in a bid to stop the spread of the disease.