The B.C. Centre for Disease Control is warning doctors to look out for new symptoms related to the deadly avian flu outbreak in Southeast Asia.

At least two children in Vietnam who died of bird flu had diarrhea and seizures rather than classic respiratory symptoms.

In the Feb. 17 issue of the New England Journal of Medicine, researchers from the Oxford University Clinical Research Unit in Ho Chi Minh City said two children died in February 2004 of acute encephalitis that was caused by the H5N1 type of bird flu.

Selling chickens at Ba Chieu market in Ho Chi Minh City, Vietnam. (AP photo)

Lab tests showed the H5N1 virus in the children's feces, raising fears that the virus could be passed from person to person.

Dr. Aleina Tweed, an epidemiologist, said doctors in British Columbia are being told to watch for gastrointestinal problems, especially in children, when they see sick people who have recently travelled in Southeast Asia.

"We wanted to make sure that the medical health community was aware that there are different presentations of this, not to be looking only for respiratory illness among people who have recently travelled to this area," Tweed said.

Dr. Richard Schabas

• FROM FEB. 23, 2005: Canada, U.S. heed WHO flu warning, prepare for pandemic

Late last year, doctors in B.C. were put on high alert to watch for signs of avian flu in people coming back from Southeast Asia. World Health Organization experts believe the H5N1 flu strain poses the single greatest threat of a pandemic in humans.

Pandemic preparations

Some infectious disease specialists say there is no need to panic.

"What I'm questioning is this escalating rhetoric, led by the World Health Organization, that's trying to tell us that in fact we are on the verge of a pandemic," Dr. Richard Schabas told CBC Radio's The Current.

"I don't think we really know what it is that triggers a pandemic, what it is that causes a particular virus to transform itself," added Schabas, Ontario's former chief medical officer of health. Tweed said while it is troubling to hear reports of new symptoms, a bird flu pandemic is not possible unless the virus spreads easily from one person to another. There is very little information now about that risk.

In Asia, it is more common to get H5N1 directly from poultry, according to the UN Food and Agriculture Organization.

"We certainly concur with the WHO that this is a very serious threat. Whether it is a threat that will manifest itself, there's no way to know, until it actually happens," Tweed said.

"Whether it will happen this week, this month or never, we simply can't predict," she said. "But we wouldn't want to take the chance, and not be as prepared as we can."

The federal government acknowledged the threat in Wednesday's budget. A Vancouver-based company will receive about $20 million to develop a bird flu vaccine.