Health authorities say the H1N1 flu may have jumped from a farm worker to pigs in Alberta, in what could be the first case of human-to-animal transmission of the virus.
CTV News has confirmed that authorities believe the worker had returned to the farm from Mexico after contracting the disease, which was then passed on to the animals.
Dr. Neil Rau, an infectious diseases specialist, said the latest twist -- if true -- may not signal any added danger to humans.
"We know that eating pork is not the way in which we get this virus," he told CTV Newsnet. "All of the cases have been person-to-person transmissions, so even if this virus is in pigs, in terms of an immediate risk we have nothing to worry about."
But he urged long-term surveillance of pigs and other livestock, "to make sure something different isn't going on."
Scientists believe the H1N1 virus, or so-called "swine flu," has been passed from human to human for some time. But even though the virus contains swine flu genes, the World Health Organization says there is no evidence pigs are passing the disease to humans.
Canadian health authorities say the virus found in the Alberta pigs is the same strain of H1N1 found in human cases around the world.