bird flu outbreak to hit australia within a year,

September 09, 2005
AS the US counts the cost of Hurricane Katrina, Australian scientists fear a more lethal storm is brewing in the poultry farms and duck ponds of Asia, one that could spread worldwide and dwarf the fear, panic, social disruption and economic damage in New Orleans. At the eye is avian influenza A virus H5N1, a bird flu that can infect and kill people. In Asia, it has killed 57 since early last year.

But as the virus spreads through domesticated poultry, ducks and migratory birds, the worry is it will mutate to leap the species barrier and become one of the most prolific killers in history.

In Australia, officials say the death toll could hit 44,000, although under some scenarios that number could easily double. Worldwide, the most optimistic assessment is for two million to seven million deaths, says the World Health Organisation. Up to 50 million died in the 1918-19 flu pandemic.

"I don't want to over-hype this," says Andrew Cuthbertson, chief scientific officer at vaccine manufacturer CSL in Melbourne. "But the SARS situation, or the [Boxing Day] tsunami, or the recent hurricane [Katrina], would be minor events compared [with] a global flu pandemic."

DEATH BY INFLUENZA
1918-19: Between 20 million and 50 million die worldwide from a Spanish flu pandemic, believed to have originated in Asia. Worst hit are young men.
1957: Asian flu pandemic, first identified in China, kills an estimated one million worldwide, with schoolchildren and young adults the main victims.
1968: Hong Kong flu global pandemic leaves at least 750,000 dead.
1997: First documented human infection with avian flu virus H5N1 in Hong Kong. Eighteen people contract severe respiratory problems. Six die.
2003: H5N1 strikes again in Hong Kong. Two people are infected and one dies. A different strain, H7N7, infects Dutch poultry farms, infecting 83 people and killing one. H5N1 outbreak in South Korean poultry.
January 2004: First outbreak of H5N1 in Japan; outbreaks in Thailand and Vietnam infect 11 people and kill eight.
June 2004: China, Indonesia and Malaysia begin reporting cases. Death toll reaches 23.
November 2004: World Health Organisation warns the H5N1 strain could trigger a worldwide pandemic that would kill millions of people.
February 2005: First case of human infection with H5N1 from Cambodia.
June: Australia releases flu pandemic disaster management plan, warning up to 44,000 people could die without a vaccine or treatment.
July: First case of human infection in Indonesia.
August: Latest estimates cite 112 cases of human infection with the H5N1 virus, 90 in Vietnam, 17 in Thailand, four in Cambodia and one in Indonesia. Death toll since January 2004 hits 57.
Sources: Nature, WHO, US Centres forDisease Control and Prevention, Australian Government.



Events in New Orleans are a wake-up call for disaster planners, says Alan Hampson, deputy director of the WHO Collaborating Centre for Reference and Research on Influenza in Melbourne. "There's probably a 10 per cent chance of this starting in the next 12 months," Hampson says.

Australia's chief medical officer John Horvath discounts that level of threat, saying there's only a 10 per cent chance of a pandemic "sometime in the foreseeable future", up to five years or so.

Horvath says Australians won't face a New Orleans-style breakdown of social order resulting from a failure of government to launch immediate help. "I don't think there's any comparison with what happened in New Orleans," he says. "New Orleans and the tsunami hit in a matter of hours. And a flu pandemic would not involve an instant mass destruction of infrastructure. Nor would it strike as a bushfire all over Australia at once."

Australia has been planning for a pandemic since 1997, he says. As well, the two most recent flu pandemics - in 1957 and 1968 - were far less lethal than the 1919 outbreak, killing perhaps a million people each worldwide and fewer than 500 in Australia.

The first transmission of H5N1 to humans was in Hong Kong in 1997, affecting 18 people and killing six of them. Since then there have been outbreaks in poultry in China and across Southeast Asia. In the past 20 months, 112 people have become ill and 57 have died.

But to cause a pandemic the virus must evolve and transmit from human to human. It could do this by mixing with a flu virus better adapted to mammals, perhaps in a pig, cat or human. If that happened, the most likely place for it to strike would be Asia, where people live closely with infected birds. From there it would be a plane trip to Australia. Infection would be rampant, given human immune systems have never encountered this strain before.

Even though Australia is arguably the best prepared of any country, Canberra's modelling suggests that without vaccine, 13,000 to 44,000 could die, up to 148,000 could be hospitalised, and maybe 7.5 million people could make outpatient visits.

A US plan, cited earlier this year by federal Health Minister Tony Abbott, points to lawlessness and looting in the wake of a pandemic. "Rates of absenteeism in schools and businesses begin to rise," the plan says. "Exaggerated accounts of illness are reported by the media. Citizens begin to clamour for vaccine but only 10 per cent of the estimated need is available. Hospitals and outpatient clinics become severely short-staffed when the majority of physicians, nurses and other health care workers become ill. Family members become distraught and outraged when loved ones die within a matter of a few days. Looting becomes a serious problem in major metropolitan areas due to shortages of police officers."

Australian officials expect a pandemic would last at least two months and return in a second wave within the year. A quarter of the population, or five million Australians, could be infected. In the worst pandemics, 2 per cent to 25 per cent of those infected have died, Horvath says.

Flu viruses are highly contagious, spreading in droplets when an infected person coughs or sneezes. The infection occurs in the nose, throat and lungs. As the body fights back, headaches, fevers and aches are typical. Complications can kill, especially in the old and young. As the immune system struggles to cope and the lungs fill with fluid, the biggest danger is pneumonia. Infection can spread to other organs, causing them to fail. As well, those who are infected may not know it, but they are infectious for a day before symptoms appear. Typically the flu lasts four or five days, but an adult is infectious for up to a week and children up to a fortnight.

Canberra's plan is to contain the disease in zones: "[But] if there is an explosive spread within the population, containment may not be possible. [Then] the strategy will shift to an emphasis on maintenance of essential services." The plan includes quarantine centres and fever clinics, bans on mass gatherings and closures of schools and childcare centres.

Peter Curson, director of health studies at Macquarie University, is not convinced Australia's health system would cope. He questions whether the pandemic plan will go as smoothly as the Government says, claiming most outbreaks of disease are marked by squabbling between state and federal authorities. "My real criticism is there's no hint of how public anxiety, fear, panic and hysteria would be managed," Curson says. "People really do have deep-seated fears about contagion and how well a government might protect them, particularly when there's no cure."

But Horvath is confident the hospital system would cope and says Curson is wrong to say there would be no cure, as even in the worst pandemics most survive. Horvath also points to a detailed, six-stage plan and more than $100 million spent on medical defences. Canberra has bought 3.3 million doses of the anti-viral drug Tamiflu, which would be used to block the disease for one million emergency workers until a vaccine can be made. The drug could also treat the ill.

Also, the Howard Government has funded CSL -- one of a handful of vaccine makers in the world -- to produce a vaccine based on the H5N1 virus. A trial vaccine will be given to about 200 volunteers in Melbourne and Adelaide next month. If the trials work and the virus strikes, it would take six weeks for CSL to produce up to one million doses a day, with two shots likely. It would take another six weeks to produce enough for all Australians. If it is a different strain, then weeks and months would be added to the preparation time, Cuthbertson says.

Masks and protective clothing have also been stockpiled and thermal imaging equipment bought for airports to screen incoming passengers for heat levels. But because a person is infectious before they show symptoms, heat sensors cannot detect all carriers.

Some optimistic analysts believe it is possible to contain the initial outbreak so it doesn't spread. For Australia, early detection would be crucial to allow CSL to start production in time for widespread vaccinations. But it is most likely to happen in a place well away from sophisticated medical surveillance, thus foiling attempts to quarantine the source and dose locals with the WHO's stock of anti-viral drugs.

"If it's in the backblocks of Laos or Cambodia, how quickly would you know what's going on?" Hampson says. "It's a hope, but not a very strong one, that we could prevent a pandemic."

And while Australia is possibly the best equipped to handle a pandemic, Canberra's acquisition of drugs and its guarantee of CSL's vaccine may raise problems with Asian neighbours. Would Australia keep back its medical stockpile or divert it and precious vaccines to those closer to the eye of the storm? "We're very conscious that in a true global crisis, countries would have to look after themselves, at least initially, because it's likely countries would close their borders," Cuthbertson says.

Hampson says some colleagues would like to see a more equitable distribution of medicine. "But if the world only has the capacity to make 300-400 million doses of vaccine, it would be a game government that allowed its vaccines to go elsewhere," he says.