The agency had said last week that H5 avian influenza was found on a farm in Woodstock, Ont. It had placed the infected premises and eight other farms under a quarantine.
That quarantine was broadened over the weekend as a new control zone — stretching out in a 10 kilometre radius from the infected farm in southwestern Ontario — was established.
"This decision was not made based on any increased risk, nor is there a food safety concern," Dr. Abed Harchaoui, a senior staff veterinarian at the CFIA, told reporters.
"This move is precautionary and to date only one farm has shown signs of infection."
The zone is meant to control the movement of animals, animal products and equipment in the region to minimize the spread of the disease, Harchaoui explained. It is also expected to help allow trade to continue in non-infected areas in the province, he added.
"This move is an effective balance between strong disease control methods and the ability to resume trade," Harchaoui said. "The agency is monitoring these additional premises closely for any sign of disease."
Quarantined farms will need licences to move products out of their premises and any dead birds found in those locations will be tested for the disease, the agency said.
Poultry farmers are also being urged to exert "extra vigilance in biosecurity measures," which includes minimizing the opportunity for wild birds to come into contact with their poultry, Harchaoui said.
Avian influenza strains circulate in migratory wild birds and waterfowl, which could spread the disease, he noted.
The CFIA's new control zone effort has been recognized by the United States, Canada's largest trading partner, which will resume trading poultry products with areas outside the zone on Monday.
Japan, Taiwan, Hong Kong, Uruguay and Barbados, however, have imposed trade sanctions as a result of the Ontario outbreak.
The control zone is expected to remain in place until the CFIA is confident avian influenza is no longer circulating in the area, Harchaoui said.
"It is expected that the establishment of this zone will contribute to the alleviation of market access restriction," he said. "We remain committed to sharing information with our trading partners and responding to their questions."
About 10,000 turkeys on the infected farm in Woodstock died of the disease and the remaining 35,000 were humanely euthanized over the past week in an effort to stop the virus from spreading, Harchaoui said.
The virus that was detected on the farm has been found to be nearly identical to the strain that triggered avian influenza outbreaks in British Columbia and nine U.S. states since late last year — the H5N2 virus.
The virus is a new hybrid from an H5N1 virus that has been decimating poultry flocks in Asia since late 2003.
Avian influenza does not pose a risk to food safety when poultry and poultry products are properly handled and cooked.
The disease rarely affects humans that do not have consistent contact with infected birds.