Flu in the coop

Sylvain-Jacques Desjardins | Infectious diseases professor Brian Ward was giving a crash course on the avian flu to reporters, when the vaccine specialist delivers a shocking thought: our country's next bird flu outbreak could jump to humans and kill as many as one in every 10 Canadians.

"A 10 percent mortality rate from a flu pandemic could be a conservative estimate," Ward says, adding flu strains already kill up to 5,000 Canadians per year.

Scary stuff. Yet Ward, who is chief of infectious diseases at the McGill University Health Centre, gets scarier. He observes the nine reporters assembled and adds: "We are 10 people in this room and one of us could die when a new pandemic breaks."

Ward's predictions are especially frightening given that the recent bird-flu outbreaks in British Columbia's Fraser Valley have prompted federal health authorities to order the preventive slaughter of 19 million B.C. fowl this week. The unprecedented measure is meant to avert a worst-case scenario: that the avian flu strain (H7N3) could spread to fowl across the country and potentially infect humans.

"The question isn't if there will be another pandemic, but when," cautions Ward.

Historically, great flu pandemics have periodically emerged and attacked 25 to 35 percent of the population, he explains. Among the flu pandemics of the 20th century, the 1918 Spanish flu caused over 40 to 50 million deaths worldwide, while the 1957 Asian flu and the1968 Hong Kong flu killed hundreds of thousands of people around the globe.

Many national governments and international organizations are bolstering efforts to quash new flu bugs should they emerge, says Ward. "Each year, we're learning more and more about the flu virus."

Before everyone rushes to buy facemasks across the country, however, consider the danger of a flu pandemic is currently low. "Flu season is now over in Canada," stresses Ward.

He also emphasizes B.C.'s avian flu doesn’t seem capable to readily infect humans as the strain that infected chickens in many parts of Asia this winter. "The Asian bird flu is also more pathogenic for the birds themselves than the versions we've seen in B.C. and the U.S."

Canadians can also take comfort that Ward is part of scientific team that hopes to establish a clinical and lab network to test candidate avian flu vaccines as rapidly as possible. To be called the Network for Emerging Biological Threats (NEmBiT), the group will be comprised of eight clinical sites in Quebec City, Montreal, Vancouver, Calgary, Winnipeg, Toronto, Ottawa and Halifax, which are currently sites of the Canadian Association for Immunization Research and Evaluation (CAIRE).

It now takes at least 10 to 12 weeks to test the annual flu vaccine in a limited number of subjects. The NEmBiT network, which could be established as early as autumn 2004, would use sophisticated computer programs to speed up vaccine evaluation in what clinical scientists call, "real time."

Ward says flu vaccines are extremely difficult to develop because the bug is constantly mutating. Yet the combined research power of the CAIRE cross-country network, says Ward, could vaccinate up to 400 Canadians per day and permit much more rapid distribution of a candidate vaccine.

Q&A on the avian flu:

Can a person catch the avian flu from eating a chicken?

Not likely, says Ward: "Standard food precautions should protect you."

What is avian influenza?

Avian flu typically infects birds but can also infect pigs, horses, seals and whales.

Can avian viruses infect humans?

Yes, but not usually. A strain of avian flu (H5N1) infected 34 people in Asia last winter and caused 23 deaths.

How do birds spread the disease?

Certain water birds shed large amounts of avian viruses in their feces. Other birds or animals become contaminated through fecal-oral transmission.

How can avian flu jump to humans?

Although some avian influenza viruses appear to be able to infect humans directly, the nightmare scenario would be the emergence of a 'recombined virus, which has characteristics from two parent viruses says Ward, this [bug] would have the capacity to spread easily from human-to-human, yet with the lethality of an avian virus. Recombined viruses could theoretically arise in birds, in humans or pigs. I

How does avian flu affect people?

Symptoms are highly variable from classic 'flu' (e.g.: fever, cough, sore throat and muscle aches) to uncomplicated eye infections. The most serious cases usually involve acute respiratory distress and viral pneumonia that can become life-threatening.

What are the odds of an influenza pandemic?

With over one billion people traveling worldwide, such a virus could spread quickly. Because avian viruses usually don't infect humans, people have little or no immune protection against them. "Children are particularly vulnerable," says Ward, "since their immune system is much more naive."

Is there a cure for avian flu?

Although some drugs exist to prevent or to treat influenza virus infection, there would simply not be enough of these medications available to protect people around the world in the event of a 'full-blown' pandemic. What's more, some viral strains are resistant to these medications. The best protection would almost certainly be afforded through the development of a pandemic strain Influenza vaccine. The development of such a vaccine would inevitably take some time.

How are flu shots prepared?

Vaccines are developed in eggs. "If a pandemic hit it might be difficult to find an egg to eat," says Ward, tongue-in-cheek.

How long could a pandemic last?

Once a new pandemic emerges, it typically circulates for 1 to 3 years.

Q&A courtesy of Brian Ward and the U.S. Centers for Disease Control and Prevention.