young most at risk under 15

YOUNG, healthy people are more likely to succumb to bird flu, raising fears that a pandemic may disproportionately kill children and those in early adulthood.

Tony Cunningham, the director of the Westmead Millennium Institute for Medical Research, said an analysis of Asian cases showed that healthy people apparently mounted such a powerful immune response that the resulting inflammation could cause death by overwhelming their lungs and other organs.

He called lung failure, "the most feared complication of bird flu … unless they are supported in intensive care the patient will die very quickly indeed".

Examination of human cases of the H5N1 bird flu in Asia since 2003 showed the virus had killed 90 per cent of infected children under the age of 15, Professor Cunningham told a scientific briefing in Sydney yesterday.

This was the opposite of ordinary seasonal flu, in which older people and others with weakened immunity were more likely to become severely ill.

He said in some people exposure to H5N1 provoked a rapid and massive proliferation of cytokines - a form of inflammation that is usually protective.

It was likely some people were genetically predisposed to such a "cytokine storm" reaction, Professor Cunningham said. It might be possible to treat them with new anti-inflammatory drugs that are used in conditions such as rheumatoid arthritis and Crohn's disease, but this approach had not yet been studied.

Fears of a bird flu pandemic among humans rose this week after the discovery that a cat had become infected in Germany.

Although the infection was relatively unlikely to spread from cats to humans, any transmission between species was of concern, said Ian Barr, the deputy director of the Melbourne-based World Health Organisation's Collaborating Centre for Reference and Research on Influenza.

Dr Barr told the meeting H5N1 probably caused more serious disease "than any flu virus we have ever seen, possibly with the exception of the 1918 [outbreak]".

In the 1918 pandemic, a bird flu virus mutated and spread directly between people - the scenario most feared now. In 1957 and 1958, a bird virus combined with elements of human flu but it was less likely to be fatal.

http://www.smh.com.au/news/national/bird-flu-young-at-most-r isk/2006/03/01/1141191732196.html