TORONTO (REUTERS) - The husband of a woman who tested positive for the H7N9 avian flu virus earlier this week was also infected, likely from a common source during their visit to China, Canadian federal and provincial governments confirmed on Friday.

The couple, residents of British Columbia, exhibited symptoms one day apart and likely did not infect each other, Canada's chief public health officer and British Columbia's deputy provincial health officer said in a joint statement.

Evidence suggests the virus does not transmit easily between humans, with most known cases involving exposure to live poultry, the health agencies said.

Their cases are the first documented cases of H7N9 infection in North America.

The H7N9 virus has not been detected in birds in Canada.

The virus first infected three people in China in March 2013.

In 2014, it infected 453 people, killing 175 of them, according to the World Health Organisation.