Preliminary tests show that a strain of H5 bird flu has been found in a duck on a commercial farm in British Columbia's Fraser Valley.

B.C. government officials say they are not sure which strain of the H5 avian bird flu was found in the duck, but stress there is no risk to human health.

Under strict protocols put in place after an avian outbreak in the area in 2004, the Canadian Food Inspection agency has put the farm where the duck was found under quarantine.

Officials won't reveal the exact location of the farm, but say it is located in the central Fraser Valley near Abbotsford. The CFIA is visiting farms in a five kilometre radius around the infected premises to test birds and is warning bird owners to practice strict biosecurity.

"Due to the precautionary principle, it's really important to lock down as quickly as possible and make sure we quarantine before it spreads further," said Dr. Eric Young, B.C.'s deputy medical health officer.

Young said there's no evidence of any sickness in any of the birds on the premises. Officials won't reveal why the tested duck was pulled from a processing plant.

"We know avian influenza is common in waterfowl. It appears to be a finding we might find in any duck. Unfortunately it's in a commercial duck so the CFIA is taking this very seriously,'' added Young.

Swab samples from the infected duck are on their way to the Canadian Science Centre for Human and Animal Health in Winnipeg, which houses one of the world's most secure labs for the testing of deadly diseases. .

Dr. Jim Clark, with the CFIA, said he isn't surprised by the finding.

"I think it was something we could anticipate was going to happen in the domestic waterfowl population," he told CTV. "We know that waterfowl are the natural reservoirs of all the avian influenzas. It was something that could have been anticipated. However, now that we've made the discovery, we're going to have to deal with that situation."

Previous outbreak

In 2004, an outbreak of avian flu eventually hit farms in a 70-kilometre swath that covered Vancouver's eastern suburbs to Chilliwack in the eastern Fraser Valley.

That outbreak was of the highly pathogenic H7N3 strain, which forced the slaughter of 17 million birds.

In the end, about three million birds were found to be diseased and the rest were allowed to be sold to consumers.

That outbreak proved officials need to act quickly and aggressively when dealing with a possible outbreak, said Clark.

"We'll be on the farm (Saturday) sampling additional ducks, just in case we can't find anything significant from that one sample. If we can find something useful from that sample, in other words, a live virus and the ability to grow it, then we'll have results relatively quickly -- maybe as soon as Tuesday or Wednesday of next week."

Clark said wild ducks in various locations across Canada have carried the H5 virus, including Quebec and Manitoba. The B.C. duck may have had contact with wild ducks that carried the H5 virus.

The government has previously said that a form of H5 avian flu virus had been found in wild birds in B.C.

Two subtypes of the avian viruses -- the H5s and the H7s -- are sometimes found in what is known as a highly pathogenic form. Those viruses decimate poultry stocks.

Friday's news comes as health officials around the world are on the watch for the H5N1 strain of the avian virus. Experts fear that strain could mutate enough to allow it to transmit among humans.