The fickle nature of the flu kept health officials from getting too confident or complacent Saturday as the number of deaths from the swine H1N1 virus appeared to be levelling off in Mexico, belying a widening caseload elsewhere in the world — particularly the U.S. and Canada.
Indeed, as the caseload in Canada jumped from 51 to 85, government sources told The Canadian Press that officials were investigating cases of pigs in Alberta becoming infected by the H1N1 strain, the result of a farm worker who fell ill shortly after returning from a trip to Mexico.
It’s believed to be the first time this particular swine flu virus, which is made up of mutated swine flu genes, is believed to have jumped to humans sometime back and has since been passing person to person.
The World Health Organization has insisted there is no evidence that pigs are passing the virus to humans, or that eating pork products poses an infection risk.
Nova Scotia, where Canada’s first cases emerged last weekend, reported 17 new cases — six of them, notably, emerging in Halifax, well beyond the environs of the small-town private school where the initial cases first surfaced following a school trip to Mexico.
That brought the provincial total to 31, the largest single share of Canada’s total caseload of 85. Alberta reported seven new cases and British Columbia three, with two new cases in Ontario and one in Quebec.
Eleven of the new cases in Nova Scotia involve students who were exposed to the virus at the private King’s Edgehill school in Windsor, N.S., said chief medical officer of health Dr. Robert Strang.
Strang said it won’t be clear for a while whether any of those infected in Halifax had contact with students, or if they contracted the illness from other sources.
"This is not a surprise," Strang said. "We fully expected to see more cases, as I’ve been saying all week. We also expected it would spread beyond King’s Edgehill school."
Mexico, the epicentre of the outbreak, reported no new deaths overnight, although its confirmed caseload jumped to 443. There were 179 confirmed cases in the U.S. and more than 80 in Canada. So far, swine H1N1 has been confirmed in just 17 deaths — 16 in Mexico and one in the U.S.
The comparatively small death toll so far, coupled with tests that show the Mexican outbreak is less widespread than first believed and research indicating the virus may not be as virulent as first thought, are good signs, officials admit. But now is not the time for people to let their guards down, they warn.
"We have seen times where things appear to be getting better and then get worse again," said Dr. Anne Schuchat, the interim science and public health deputy director with the U.S. Centers for Disease Control and Prevention.
"I think in Mexico we may be holding our breath for some time."
So far, the virus has largely confined itself to points north of Mexico. So far, 15 cases have been confirmed in Spain; 13 in Britain; six in Germany; four in New Zealand; two in Israel, France and South Korea and one each in Italy, Switzerland, Austria, Hong Kong, Denmark and the Netherlands.
If the outbreak has kindled bad memories of the SARS outbreak of 2003, it was most evident in Hong Kong, where a single case touched off aggressive efforts to track down anyone who may have come in contact with a 25-year-old Mexican tourist who fell ill while on vacation.
Some 305 guests and staff were sealed inside the Metropark Hotel after the guest, who was in hospital and stable Saturday, began showing flu symptoms. Fifteen of his fellow passengers have also been sent to hospital for testing.
South Korea reported Asia’s second confirmed case — a woman just back from Mexico — and other governments also prepared to quarantine passengers, eager to show how they have learned from 2003, when Hong Kong was criticized for imposing quarantines too slowly.
The U.S. is taking "all necessary precautions" now to be prepared if the swine flu develops into "something worse," President Barack Obama said Saturday in his weekly radio address.
"This is a new strain of the flu virus, and because we haven’t developed an immunity to it, it has more potential to cause us harm," Obama said.
"Unlike the various strains of animal flu that have emerged in the past, it’s a flu that is spreading from human to human. This creates the potential for a pandemic, which is why we are acting quickly and aggressively."
The World Health Organization said it has sent 2.4 million treatments of anti-flu drug Tamiflu to 72 developing countries, taking the drugs from a stockpile donated by Roche Holding AG.
"At this point it’s important that all countries have access to antivirals," said Dr. Mike Ryan, WHO’s global alert and response director.
The WHO has decided not to raise its alert to a full pandemic, instead holding steady at Phase 5 — a level that indicates a global pandemic could be imminent — since the virus has yet to cause sustained transmission outside North America. But Ryan warned against complacency.
"These viruses mutate, these viruses changes, these viruses can further reassort with other genetic material, with other viruses. So it would be imprudent at this point to take too much reassurance" from signs the virus is weaker than feared.
Mexico has taken extraordinary measures to combat the epidemic, ordering all nonessential government and private businesses to shut down for five days, at a tremendous cost to its economy. In the wide valley where traffic and crowds can be stifling even on a Saturday, Mexico City streets were strangely quiet, its usually crowded markets shuttered and even parks locked down.
"I’m going crazy in my house with this confinement," retiree Rocio Lara said in Mexico City. "There is nowhere to go, nowhere to spend your time."
Mexico City’s mayor Marcelo Ebrard said they had expected exponential growth in the number of persons complaining of swine flu symptoms, and that the outbreak seems to be slowing instead.
It should soon become clear whether the epidemic is really stabilizing in Mexico, but many questions remain about how the disease kills, said the leader of an international team of flu-fighters now operating in the capital.
"That is the big question: Is it stabilizing or not? And it is too early to say, but I think we are getting systems in place where we are going to be able to get a handle on this soon," said Dr. Steve Waterman of the CDC.
Waterman also warned against taking false comfort from the fact that only one person has died outside Mexico, saying more deaths are likely as the epidemic evolves.
The U.S. government said schools with confirmed cases should close for at least 14 days because children can be contagious for seven to 10 days from when they get sick. More than 430 U.S. schools have closed, affecting about 245,000 children in 18 states.
In Canada, only one school, an elementary school in Vernon, B.C., has shut its doors as a result of an infected student.
Scientists trying to determine the mortality rate have said the current H1N1 strain does not appear to match the ferocity of past killers.
"Most people think it is unlikely this is going to be as virulent as the 1918 epidemic. From what we know so far, it doesn’t seem like it is as virulent," Waterman said.
"The virus has been circulating for over a month in a city of 20 million of high population density. It could have been much worse," agreed CDC epidemiologist Marc-Alain Widdowson.
The two CDC doctors spoke during a tour of Mexico’s Intelligence Unit for Health Emergencies, where teams of doctors and scientists monitor the outbreak in real time and plasma screens enable frequent video conference calls with leaders from the Atlanta-based CDC, the World Health Organization and other institutions.
Health Secretary Jose Angel Cordova cited other indications that the disease is not very contagious: Mexican investigators who visited 280 relatives of victims found only four had contracted the disease, and that the number of people hospitalized with suspected cases is declining.
But it’s far too early for the government to declare the epidemic is subsiding, he insisted.