The H5N2 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 this week.  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. The affected farms were immediately placed under quarantine

“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.

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 origin of the virus is unknown but officials are looking into the possibility that migrating wild birds introduced the virus to the region.

Avian influenza outbreaks have occurred previously in British Columbia and elsewhere in Canada. The most serious was a 2004 outbreak in the Fraser Valley that prompted federal officials to order the culling of about 17 million birds.