Australian Broadcasting Corporation
Broadcast: 26/05/2009
In the last 10 years three animal-derived flu viruses threatened Australia, with none progressing to become lethal pandemic on the scale of the Spanish influenza. However scientists warn such viruses are unpredictable, and countries are complacent in their approach to protecting their population.
Transcript
TONY JONES, PRESENTER: In the last 10 years three animal derived flu viruses have threatened Australia - bird flu, horse flu and swine flu. So far, none have gone on to become lethal pandemics on the scale of the 1918 Spanish flu. Yet scientists closest to these superbugs warn they are still highly unpredictable and that some countries are becoming complacent in their approach to protecting their populations. So how seriously should we take these warnings? Ticky Fullerton reports.TICKY FULLERTON, REPORTER: Another day, another suspected dose of swine flu for an unlucky Australian.
It's nothing, though, to the panic caused when swine flu H1N1 first appeared in Mexico in April. By 29th April, the World Health Organisation had upgraded its pandemic alert to a level five out of a possible six.
MARGARET CHAN, DIRECTOR GENERAL, WHO (30 April, 2009): It really is all of humanity that is under threat during a pandemic.
TICKY FULLERTON: Despite best efforts of border control, H1N1 is now at large, killing fewer, but still highly contagious.
Forty-six countries have so far reported over 1,200 cases, over 6,000 of them in American and 300 in Japan. Just 91 people have died, almost all in Mexico.
It is the unpredictably of flu viruses - the "known unknown" - that causes alarm.
In 1918, the Spanish flu arrived as a mild case in spring, but in the autumn returned to kill an estimated 40 million. It's most likely genesis was from a bird influenza.
JOURNALIST (archive footage, '7.30 Report', Jan. 2004): Across Asia, chickens are meeting a grizzly end. It's a slaughter without precedent that's seeing millions simply stuffed into sacks and buried alive.
TICKY FULLERTON: It's bird flu, not swine flu that scientists fear most.
MALIK PEIRIS, UNI OF HONG KONG: Of all the options that are out there that threaten to become pandemic, H5N1 Avian flu is the most lethal and the most severe. So that is why attention was focused on H5N1.
TICKY FULLERTON: The first six bird flu deaths came in 1997, but it struck with a vengeance in 2003.
Unlike swine flu H1N1, bird flu H5N1 is normally transmissible only from bird to human. But its potency is frightening - a 60 per cent fatality rate in humans.
Most disturbing for flu experts like Dr Malik Peiris, bird flu is still incubating in poultry in developing countries.
MALIK PEIRIS: Bird flu H5N1 certainly is endemic in many countries across Asia and parts of Africa such as Egypt, as you mentioned. And I do not see any likelihood that that situation is going to change in the near future.
TICKY FULLERTON: Unsurprisingly, the human toll from sporadic outbreaks has continued in recent years, albeit at lower levels, particularly in China, Egypt, Indonesia and Vietnam. It means bird flu is a constant threat.
MALIK PEIRIS: If that virus were to become pandemic, if that virus were to acquire transmissibility, the outcome would be really devastating.
TICKY FULLERTON: Australian scientists have been at the forefront of diagnosing deadly flu viruses.
Tonight, the Australian Biosecurity Cooperative Research Centre picks up an innovation award for developing a highly effective test for avian influenza.
In 2007, that test became a vital tool in the battle against another devastating virus, equine flu. In January this year, Australia was declared free of horse flu - the only country in the world to eradicate the disease.
But for tonight's award winner, the message is that a bird flu pandemic is still a real risk.
STEPHEN PROWSE, CEO, AUSTRALIAN BIOSECURITY CRC: Influenza that's causing bird flu, that's the H5N1 influenza, is still present in many countries round the world. It's still causing disease in birds and it's still causing disease in humans. And it's still causing death of humans.
JOURNALIST (archive footage, Feb. 2006): But this senior health official in charge of the testing program at the bird market showed us what he thought of the threat.
TICKY FULLERTON: In recent years, Asian countries like Thailand and Indonesia have been criticised for their handling of bird flu. The WHO now warns that countries are developing flu fatigue.
STEPHEN PROWSE: WHO and a number of other people made comments that a pandemic was imminent, that the there was a high risk of a pandemic. In fact, that hasn't really eventuated. And there's been a little bit of tension to the concept that the scientists and WHO have been crying wolf. And in fact I think that's far from correct.
MALIK PEIRIS: I think that the problem with the avian flu H5N1 is extremely challenging, particularly so for countries with a relatively weak infrastructure in terms of animal husbandry. And, I mean, countries such as Vietnam really did a superhuman effort in 2005/2006 and brought the avian flu H5N1 under a measure of control. But I think in the end the virus has re-emerged even in Vietnam.
TICKY FULLERTON: The emergence of swine flu and new evidence from Canada that it has already jumped from humans to pigs shows just how unpredictable a flu virus can be. Pigs, the mixing vessel, can host swine, bird and human varieties.
STEPHEN PROWSE: Every time it goes through a cycle of replication, you get errors creeping in to that replication process. And, so each of the viruses that come out of those hosts are - will be a little different from each other. So, they then have the capacity to infect the hosts in a slightly different way.
TICKY FULLERTON: Viruses can also swap chunks of genetic material if two infect the same host. One possibility is that bird flus and human flus swap potency and transmissibility. Of course, none of this is inevitable.
MALIK PEIRIS: Human viruses have been established in pigs, certainly in Asia, for the last eight or nine years. And, clearly, the avian flu virus would have met human viruses in pigs, and that mixing, that reassortment, between H5N1 and the human H3N2 did not occur.
TICKY FULLERTON: Perhaps the most chilling potential for a virus is to develop resistance to drugs like Tamiflu.
Already, human flu strains are showing resistance and there have been some cases of resistance by bird flu.
STEPHEN PROWSE: One of the real concerns would be is if there are joint infections between bird flu and the new swine flu and there is recombination and exchange of genetic information between those two viruses. And that could present a real risk in that you might get a bird flu that spreads more easily from human to human, or a swine flu that actually has drug resistance.
TICKY FULLERTON: If you are one for probabilities, we are due for a pandemic. Over the last 100 years, there have been three, but the most recent was 40 years ago. Ticky Fullerton, Lateline.
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