The avian influenza outbreak in southwest British Columbia has spread to seven farms, and 155,000 birds have died of the virus or will be euthanized, the Canadian Food Inspection Agency said.

The outbreak began last week when turkeys and chickens at two farms in the Fraser Valley east of Vancouver tested positive for the H5N2 strain of the disease. Its origin is unknown, and more farms could be affected, officials said.

"The identification of additional farms is not unexpected, given that avian influenza is highly contagious," Harpreet Kochhar, Canada's chief veterinary officer, said Wednesday in a conference call with reporters.

Avian influenza poses little danger to people as long as poultry meat is handled and cooked properly. But the outbreak is a blow to the local poultry industry.

Eight countries have banned or placed restrictions on British Columbia poultry and poultry products. They include the United States, Mexico, South Africa, Japan, Taiwan, Hong Kong, Singapore and South Korea. Japan's restrictions apply to all poultry from Canada.

The affected farms are in a cluster near Abbotsford and Chilliwack. In each case, officials immediately placed the farms under quarantine and made plans to euthanize any birds not already been killed by the virus.

Officials are looking into the possibility that migrating wild birds introduced the virus to the region.

Consumers are unlikely to notice the outbreak at the grocery store.

About 25,000 turkeys meant for the provincial Christmas market have been lost, but that's a relatively small portion of the 7.3 million pounds of turkey typically produced for the holiday season, according to the B.C. Turkey Farmers, a marketing group.

Likewise, the number of chickens destroyed due to the outbreak pales in comparison with the 353 million pounds of chicken produced each year in the province.

Previous avian influenza outbreaks in British Columbia and elsewhere in Canada have led to the deaths of tens of thousands of birds. The most serious was a 2004 outbreak in the Fraser Valley that prompted federal officials to order the slaughter of about 17 million birds.