TORONTO - A brand new virus diagnosed in at least two Saskatchewan hog farm workers will likely burn out with those cases, but public health authorities need to keep a wary eye on the virus in case it spreads, a leading Canadian infectious disease expert warns.
Dr. Frank Plummer, director of the National Microbiology Laboratory in Winnipeg, stressed that the novel virus is not connected to the pandemic H1N1 flu strain that has infected thousands of Canadians and been linked to 38 deaths across the country.
Tests showed two workers at a hog farm in eastern Saskatchewan had been infected with the novel virus last month and a third is suspected to have been sickened by the same agent. All three have fully recovered.
The new flu is a genetic cocktail of seasonal human flu and a long-known animal strain, said Plummer, explaining that an influenza virus that's been "circulating in pigs for many, many years picked up some new genes from the human H1N1 seasonal flu, nothing to do with this pandemic virus."
"And it's created this brand new virus that's never been seen before."
Plummer, in Toronto on Wednesday for a meeting of researchers from across Canada to discuss the H1N1 flu pandemic, said no other human cases of the new virus have been reported and "the pigs apparently look pretty well."
"So we've picked up this novel virus. We have to react very aggressively to it. But from what we know now, I think it's probably going to end with those three cases and everything will be fine."
The new strain was identified after tests on the workers came back positive for both seasonal and swine flu -- a finding that Dr. Moira McKinnon, Saskatchewan's chief medical officer of health, called unusual.
When the aberrant test results were sent to the National Microbiology Lab for further analysis, scientists discovered genes from two different flu viruses had combined.
Plummer said it's not known when this "reassortment" -- the mixing of genetic material -- occurred, but he believes it's likely the workers were infected by the pigs, not the other way around.
Nor does he think that there was human-to-human transmission because all three workers got sick at the same time. All had been in Saskatchewan for about a year and had not left the province.
"So that would be consistent with coming from a common source like one pig," he said.
While Plummer believes the chance of this new flu virus genetically recombining with the pandemic H1N1 strain is "very, very unlikely," he cautions that public health officials need to aggressively keep on top of the virus.
"We need to understand the extent of the problem: Is it just these three people or is it more than that? Is it just this one pig herd or is it more than that?"
Similar questions were being raised about pandemic H1N1 at the Wednesday meeting.
Bhagirath Singh of the Canadian Institutes of Health Research said the goal of the gathering was to allow front-line health workers, infectious disease experts, bench scientists and public health officials to share information and set up research collaborations.
"The first thing we want to achieve is to make sure there's a networking opportunity for the people ... to work together," said Singh, scientific director of CIHR's Institute of Infection and Immunity.
Such research alliances could help answer a key question that's been gnawing at scientists: why some people hit by the pandemic flu strain develop severe illness that can put them in hospital on ventilators for weeks, while the majority of those infected experience mild symptoms and recover quickly.
Singh said several possible factors need to be rigorously investigated, including what roles may be played by a person's genetic makeup, environmental influences and living conditions.
"All those issues need to be addressed," he said.
Plummer agreed that experts don't have a good handle on the variation in severity of illness, "and if we understood it better, we might be able to take measures to try to prevent that."
He said researchers also need to stay alert about how the H1N1 flu virus affects the Southern Hemisphere, which is already experiencing a widespread outbreak.
It is also important to obtain a clearer picture of how many cases there have been in Canada, since the roughly 9,000 lab-confirmed cases represent only a small fraction of the total number who contracted the disease, Plummer said.
But the turnout of so many people involved in different aspects of pandemic H1N1 flu should create a powerful team to answer these scientific questions, he said.
"Science is fundamentally a collaborative venture. No one person, or one lab has the resources to do everything, and so bringing people together in innovative partnerships is important."
