The Canadian Food Inspection Agency confirmed Saturday afternoon that avian influenza had spread to a fifth Fraser Valley farm, a turkey producer near Abbotsford, B.C.

B.C. Ministry of Agriculture Chief Veterinary Officer Dr. Jane Pritchard says the turkey farm contains two barns with a capacity of 30,000 birds each.

Farms affected by the avian flu outbreak are under tightened biosecurity measures. (CBC) ​The CFIA says given the highly contagious nature of the disease it anticipated other farms could be identified.

CFIA Chief Veterinary Officer Dr. Harpreet Kochhar says quarantine measure are in effect at each identified farm and rejected a suggestion the spread was out of control.

"Given that there is a big population of or a very dense population of poultry industry down there, it was not unexpected that we would find other additional at-risk farms because avian influenza is highly contagious," he said.

An H5 influenza outbreak in B.C.'s Fraser Valley has led to the quarantine of five farms and death of thousands of chickens and turkeys. (Associated Press)

"This can not be characterized at this moment as an out-of-control outbreak, however, we are expecting that given the virus virulence and contagiousness of the disease that we might find some other farms which could come out positive."

The CFIA says the potential addition of 60,000 more birds from the fifth farm now puts the cull of infected poultry, which is already underway, at more than 140,000 birds.

Canada's chief veterinary officer has already said the federal government will compensate farms for each bird destroyed.

World markets impose bans, restrictions

World markets have reacted to the outbreak, leading seven countries—the United States, Japan, South Korea, Taiwan, China, South Africa and Mexico​—to impose trade restrictions on poultry and poultry products from all of Canada.

Workers in bio-security suits are culling more than 140 thousand birds at five Fraser Valley poultry farms. (CBC) Hong Kong has imposed an outright ban on any poultry meat or products from the entire Fraser Valley Regional District.

It imported 7,000 tonnes of frozen poultry and about 170,000 poultry eggs from Canada between January and October of this year.

Hong Kong has had its own problems with avian flu, including an H5N1 outbreak in 2011 that led to the slaughter of more than 19,000 birds and a ban on the sale of live poultry for three weeks.

Fifth farm owner approached CFIA on Friday

The CFIA's Kochhar says the farmer at the fifth farm approached the CFIA on Friday and provided samples which were tested Friday evening and found to be positive for the H5 type early Saturday morning.

The federal government has confirmed the type of avian flu found at a turkey farm in Abbotsford and a chicken farm in Chilliwack as the highly pathogenic H5N2.

The H5 avian influenza virus has been detected at a fifth farm, a turkey producer near Abbotsford. ​Further testing at two other nearby farms that received chickens from the site have confirmed H5 avian flu, but the strain from those farms and from the fifth farm has yet to be identified. ChilliwackH5

Complicating the containment, said Kochhar, is the sheer number of poultry farms in such a small area. He said there are 42 poultry farms in a three-kilometre radius in one production zone alone.

When asked how the disease continues to spread despite CFIA quarantines, Kochhar said the flu can be spread by other sources including wild or migratory birds.

​There have been three previous outbreaks in Canada involving the low-path strain of H5N2 — two in B.C. and one in Manitoba.

Officials have cautioned that the virus does not pose a risk to consumers if poultry meat is properly handled and cooked, though in rare cases it can be transmitted to people who work in close contact with the animals.

The B.C. Poultry Association has said it is confident biosecurity measures will be able to stop the spread of avian flu in the region.

No human has become ill from an H5 influenza outbreak, according to public health officials.