April 25, 2009

TORONTO -- Canada's chief public health officer expressed deep concern about a swine influenza outbreak gripping Mexico and the southwestern United States as health officials around the world went on high alert for a potential global flu pandemic.

"This is very concerning, clearly. That's why we're all paying attention," David Butler-Jones said yesterday. "What it will lead to is impossible to predict."

Mexico shut down schools, museums and libraries in its capital yesterday in the hope of containing a never-before-seen virus that authorities say has killed 20 people - and perhaps dozens more. Hundreds in the country are suffering from a severe respiratory illness.

The virus has not landed in Canada yet, but health officials are awaiting lab results from a Crown attorney in Cornwall, Ont., who returned from Mexico last month with a mysterious illness.

Mexico confirmed that some of the respiratory illnesses were caused by a new swine flu virus similar to the one that has sickened eight people in Texas and California.

The World Health Organization started convening an expert panel to advise it about raising the pandemic alert level, which is currently at level 3 (none or very limited human-to-human transmission) in its six-rung alert ladder. One health expert expects things to move quickly in the coming days.

"In my mind, what we're talking about is moving from a pandemic alert 3 to a pandemic alert probably 5," said Michael Gardam, director of infectious diseases prevention and control at the Ontario Agency for Health Protection and Promotion. Level 5 indicates a new strain with significant human-to-human transmission. Level 6 is a pandemic.

"They're going to need a bit of time to digest it, I understand that. That being said, being very familiar with their plans and their phases, I am assuming they will come to the conclusion once they've gone through that deliberation that they need to up the pandemic threat level."

The unusual influenza A H1N1 swine virus was first reported earlier this week, when the U.S. Centers for Disease Control and Prevention announced it had found cases with the virus.

Mexico sent samples of its influenza virus to be tested at the CDC and the National Microbiology Laboratory in Winnipeg. Both labs found positives of swine flu.

Testing indicates the virus shows sensitivity to Tamiflu and Relenza, the two anti-viral drugs that Canada has stockpiled.

Dr. Butler-Jones said those who have returned from Mexico within the past two weeks and are experiencing flu-like symptoms should see their doctor.

He said a handful of flu cases have been looked at across the country, but so far none have come back positive.

Blood specimens from Cornwall lawyer Guy Simard, 47, are being tested for the virus. Health officials say Mr. Simard has since recovered.

There is no reason Canadians shouldn't travel to Mexico, as long as the usual travel precautions are taken, Dr. Butler-Jones said.

Dr. Gardam disagreed.

"My own personal opinion would be that if I was planning a trip right now and I was hearing that Mexico had just closed their schools because they're worried about transmission of a novel flu virus, I would probably rethink my travel plans," he said.

In Mexico, Health Secretary Jose Angel Cordova said 68 people have died of flu since March 18, and the new swine flu strain had been confirmed in 20 of those deaths.

At least 1,004 people nationwide were sick from the suspected flu, he said.

The cases have mainly affected healthy young adults between the ages of 25 and 44.

Mexican authorities said this could be because immunizations are given to children and the elderly, the highest risk groups.

It is believed that the new swine influenza spreads the same way as the seasonal flu and has similar symptoms, including fever and joint aches.

Richard Besser, acting director at the CDC, said in a news teleconference that he's heard high anxiety from the public.

"We are worried as well," Dr. Besser said.

The eight people in Texas and California have all recovered, although it remains unclear how they contacted the virus.

Scientists have long been preparing for a new flu virus that could cause a global pandemic.

The focus has been on the bird flu in Southeast Asia, but the virus there has not spread from person to person easily enough to touch off a pandemic.

Canada was among the first to start preparations for a pandemic, Dr. Butler-Jones said.

He added that officials have built an anti-viral stockpile and have the ability to produce a vaccine quickly for the whole country.

PAST PANDEMICS

A pandemic is a worldwide outbreak of a new disease that spreads quickly and against which people have little immunity. There have been three flu pandemics in the past century and experts say another could come at any time.

A strain of the swine flu caused the great pandemic of 1918-19 that killed 50- million people. Called the Spanish flu, the infection primarily struck young adults and is considered one of deadliest disease events in human history.

The 1957 Asian flu and the 1968 Hong Kong flu - both caused by strains of the avian flu - were considered less severe pandemics. They killed two-million and one-million people, respectively.

Another pandemic was predicted in 1976 when a strain of the swine flu was found among U.S. Army recruits at Fort Dix in New Jersey.

The United States reacted with a massive immunization campaign, inoculating 60-million people before the vaccine was recalled. Canada had already ordered three-million doses of the vaccine, which was blamed for killing 25 people in the United States and causing paralysis in others.

The pandemic did not break out as expected.

Nicki Thomas

PREPAREDNESS PLAN

WHO uses a six-phase series of alerts to inform the world of the seriousness of the threat.

INTER-PANDEMIC PHASE New virus in animals, no human cases	Low risk of human cases	1
Higher risk of human cases	2
PANDEMIC ALERT New virus causes human cases	No or very limited human-to-human transmission	3
Evidence of increase human-to-human transmission	4
PANDEMIC	Evidence of significant human-to-human transmission	5
Efficient and sustained human-to-human transmission	6

THE GLOBE AND MAIL // SOURCE: WORLD HEALTH ORGANIZATION

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