New flu virus in Sask. needs to be watched: expert
A new strain of flu virus diagnosed in at least two Saskatchewan hog
farm workers will likely disappear with those cases, but public health
authorities need to keep a wary eye on it in case it spreads, a leading
Canadian infectious disease expert warns.
Frank Plummer, director of the National Microbiology Laboratory in
Winnipeg, stressed that the novel virus is not connected to the
pandemic strain of H1N1 influenza A virus 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 Saskatchewan 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
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?" he said.