Bird flu bigger worry than SARS, says expert

A Queensland University microbiologist who led the World Health Organisation's response to last year's SARS outbreak says he is much more concerned about the potential of the new strain of avian influenza sweeping Asian poultry farms to cause a human influenza pandemic.

Prof John McKenzie told The Australian newspaper that the outbreak of the H5N1 strain of avian influenza, which has now killed 18 people -- 12 in Vietnam and six in Thailand -- represents the "worst scenario possible" for a human pandemic. "SARS was just a kind of minor thing compared to what a new pandemic of influenza would be," McKenzie told the paper.

He said it was "unprecedented" that so many countries were being affected simultaneously by avian influenza, and that there were so many cases of human infection.

Today, McKenzie told Australian Biotechnology News that it was also unusual that so many wild bird species were dying of avian influenza. Reports from China have described dead and dying birds dropping out of the sky, apparently after succumbing to the new avian influenza strain.

"Usually these avian viruses are not very virulent," said McKenzie, who has worked on influenza in the past. "Occasionally, you do see this [deaths in wild birds] happening -- the biggest involved an avian strain that caused a mass kill in terns in Africa in 1961."

Commenting on the human death toll in the current outbreak, McKenzie said it was unusual that there were so many cases of lethal human infection.

Health authorities normally warn that epidemic strains of influenza are a hazard only to the elderly -- particularly those with chronic heart or lung disorders -- or to babies, whose immune systems have not matured. Nearly all the human fatalities in the avian influenza epidemic have been children or healthy young adults.

McKenzie said that as a sexagenarian himself, he would probably go out and buy a course of Tamiflu tablets (Roche's proprietary neuraminidase-inhibitor, which can prevent or relieve an influenza infection). He said he "wouldn't mind having something" on hand, if not for a potential bird flu pandemic, which was still an unlikely prospect, then for the likely human flu epidemic this winter.

McKenzie said the Australian government had a very good pandemic plan. but recommended the government begin stockpiling neuraminidase inhibitor drugs to protect front-line medical staff in the event of a pandemic.

He said WHO officials working to contain the avian influenza epidemic in Asia were strongly recommending the use of neuraminidase inhibitors to protect workers involved in the poultry cull, because earlier-generation drugs like amantidine did not work in patients infected by the H5N1 strain.