Work on a new vaccine to guard against human swine flu is underway in a Winnipeg lab as health officials across the continent move to contain the growing threat that could spark a worldwide influenza outbreak.
The mysterious disease that initially cropped up in Mexico has spread to Canada, and countries as far away as New Zealand are testing suspected cases. There are no cases reported in Manitoba so far.
Canadian health officials confirmed six people have tested positive for a mild form of human swine flu, with four cases in Nova Scotia and two in British Columbia.
The United States has reported 20 cases. Mexican officials say the disease has killed 103 people in that country and likely sickened more than 1,600 since April 13.
Scientists are trying to figure out why the illness appears to infect a demographic that is typically untouched by severe flu -- healthy adults between the ages of 25 and 44.
Dr. David Butler-Jones, Canada's chief public health officer, said experts from the U.S. and Canada are heading to Mexico to obtain more specifics on who has fallen ill and how the disease spreads. To date, Butler-Jones said, experts have had access to information on swine flu cases from select hospitals in Mexico, which may not be providing the full picture of who is getting sick.
Often, he said, seasonal flu crops up in schools and hits young adults first before spreading to older adults.
Although the six Canadians who tested positive for the virus were only mildly ill, Butler-Jones warned that the potential severity of swine flu should not be ignored. Border officials are on the lookout for any travellers returning from Mexico who should see a doctor. Health notices advising travellers going to and returning from Mexico of symptoms that should prompt them to seek medical attention will be posted in airports later this week.
At least two people have already been directed to seek care by a border agent, Butler-Jones said: "No one should underestimate this disease."
Meanwhile, teams of scientists from the Winnipeg-based National Microbiology Lab have started work on a vaccine to protect against H1N1 swine flu and are investigating whether the existing flu shot could offer any protection from the virus.
Dr. Frank Plummer, the lab's scientific director, said scientists will test to see if the flu shot will protect animals from swine flu since the annual shot already contains H1N1 human flu virus. Plummer said there are still many unknowns about human swine flu, but said genetics or environmental factors could help explain why Mexico seems to be experiencing a more severe form of swine flu than Canada and the U.S.
Winnipeg's lab has done most of the testing of swine flu samples from Mexico. Plummer said he's had a good working relationship with Mexican health officials through the Canadian-led Global Health Security Action Group, which is why Mexican authorities approached the Winnipeg lab for help diagnosing samples on April 17. "I think we're at the beginning of this outbreak and there's a lot more that's unknown than known," Plummer said during a teleconference from Ottawa Sunday. "There are many potential explanations for severe respiratory illness in Mexico and the absence here."
Health officials in Canada are bracing for more cases. Dr. Joel Kettner, Manitoba's chief medical officer, said it's only a matter of time before the disease surfaces here.
Hospital workers are on the lookout for severe respiratory illnesses.
Kettner said anyone experiencing severe flu symptoms should see a doctor.
"The virus is turning up in not only Mexico but the southern U.S. and New York and Nova Scotia and B.C. and New Zealand. When the infection makes its way around the world it's a pandemic.
"The bigger question is how severe is it and what is it doing?"
--with files from The Canadian Press