- © 2004 Canadian Medical Association or its licensors
While trying to dispel fears that the outbreak of avian influenza A(H5N1) in Asia could lead to a pandemic, the World Health Organization (WHO) is also scrambling to produce a vaccine to protect humans (see page 785). Meanwhile, Health Canada issued a pandemic plan in mid-February and advised Canadian doctors to be on the alert for any sign of the flu among people arriving from Southeast Asia.
As of Feb. 9, the avian flu had killed 18 people in Asia.
Health Canada advises health professionals to be vigilant in recognizing, reporting and investigating possible cases. A memo in late January advised emergency physicians to collect clinical samples as soon as possible and alert public health authorities.
“If you saw someone with a severe respiratory illness that you couldn't diagnose, then you would have to consider that it could be avian flu,” said Dr. Donald Low, chief of microbiology at Mount Sinai Hospital in Toronto. “It is always critical to identify the first case.”
Health Canada warns that the avian flu could have dire results. “Our belief is that if a new, potentially pandemic influenza strain arises, it may well be a result of mixing between avian and human viruses,” said Dr. Arlene King, director of immunology and respiratory infections for Health Canada.
Low, says “The question is not if it's going to happen, but when. These pathogenic avian flu strains are not going away. They are rearing their heads more frequently and, one of these times, we will see a strain emerge that is able to spread [from human to human].”
Low says the real fear is that this virus could infect someone who is already infected with a human flu virus like A Fujian, resulting in genetic reassortment and a novel pathogen that could be highly virulent and capable of human-to-human transmission.
The avian flu virus that emerged in Hong Kong in 1997 did mutate into a form that was transmissible among humans, but the new strain was weak and caused few illnesses, notes Dr. Klaus Stohr, head of the WHO H5N1 Outbreak Response Group. Stohr says it's encouraging that the current strain of A(H5N1) seems quite similar to the one in Hong Kong in 1997.
Still, WHO isn't taking any chances. It hopes to have up to 900 million doses of a vaccine available within 4–6 months. Prototype viruses will soon be supplied to manufacturers as the “seed stock” for vaccine production. — Margot Andresen, Ottawa