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  Today Online 15 Oct 05
killing machines?
Tan Hui Leng huileng@newstoday.com.sg
Experts dread the day a human with flu meets a bird that is sick

THERE is something inherently strange about the bird flu story. If what the experts say is true, we should all be panicking about it. Instead, it barely makes headline news, which makes you wonder if it's all a huge overreaction to some chickens falling ill. Or are we just blind to a threat that could have a far bigger impact than last year's tsunami?

Consider the best piece of news that has recently come out on the bird flu front: The World Health Organization (WHO) now says that a United Nations expert may have exaggerated the threat, and a pandemic is likely to kill only between 2 million and 7.4 million people. That's right. Only 7.4 million.

It's good news only when you compare it to a statement made last month by Dr David Nabarro the man charged by UN with controlling the bird flu epidemic in which it was suggested that the disease could kill between 5 million and 150 million people. "We really don't know how many will die in a pandemic until it begins," said WHO Western Pacific spokesman Mr Peter Cordingley. "What Dr Nabarro gave was probably the gloomy end of the scale. Our official estimates is up to 7.4 million but we could be right, or he could be right."

Still, if even the best-case scenario predicts two million deaths, why aren't more countries going into panic mode? Simple: Because to work out what will really happen, you have to predict how the virus will mutate. And no one can really do that.

As things stand, the H5N1 strain, which first surfaced in 1997, has claimed 60 human lives. Experts are getting nervous because, in recent months, not only have the outbreaks accelerated, the geographical spread of the H5N1 virus has also touched at least 10 countries in Asia, including China, Indonesia and Vietnam.

And this week it has reached Europe, prompting a cull of birds in Turkey and Romania. If it had merely remained a disease that spread among birds and affected the farmers who are in touch with them, the world would not have been worried. Since humans have no immunity to the bird virus, the sufferers may even have died, but the toll would have been limited.

Now imagine a situation in which a person suffering from normal human influenza also picks up the bird flu. This is the experts' nightmare. If the bird flu virus gets "jumbled" with the human flu virus, it can mutate and spread quickly, like the common flu. But it may also kill the thousands who have no immunity to it.

That is why, on Thursday, Britain called for 10 million "high-risk" elderly people and one million children to get the winter flu jab. Europe has been jolted awake and that is natural, said Mr Cordingley. "For two years, we have been shouting from the hilltop 'Will you just listen, it's serious' but the response from the west seems to suggest that it is thought that bird flu will affect only poor farmers in paddy fields," said Mr Cordingley.

But with the birds migrating back west along with the virus, Europe is sweating. Even the United States launched the International Partnership on Avian and Pandemic Influenza last month. . Is the reaction appropriate?

It might not seem alarmist, or even adequate, if you consider that the Asian Flu of 1957, which claimed two million lives, and the Hong Kong Flu of 1968, which killed one million, stemmed from mutated bird flu viruses. Now research suggests that even the Spanish Flu of 1918, which killed 40 million, could have been triggered by bird flu.

On the other hand, the WHO cautions against a panic reaction. "This is a real dilemma for the WHO," conceded Mr Cordingley. "While the situation is very serious, we have to try to keep a sense of proportion about it."

The alarmist attitude is a particular problem in Indonesia, where there have been reports of patients being hospitalised for H5N1 when they were simply down with "old-fashioned winter flu", he said. So far, lab tests done in Hong Kong have confirmed just five H5N1 cases in Indonesia.

But the fears are growing, particularly since the world seems due for a flu pandemic. "We know a global flu pandemic is coming and the question is when," said WHO director-general Lee Jong-wook.

He added that the most important thing to do is to stop it from spreading. Dr Nabarro echoed this. "Prevention is going to be cheaper and more effective than waiting for the pandemic to occur," he said on Tuesday noting that the UN had a budget of just US$7 million ($11.8 million) to control animal flu outbreaks. This is not enough, he said, as US$175 million would be needed. This is in contrast to the hundreds of millions wealthy countries are spending on stockpiling flu treatments and vaccines.

And it is not even certain if the vaccines will work, as the one developed for H5N1 was based on the strain from Vietnam. Because the flu virus mutates so fast, there is no telling if the vaccines will work should a pandemic start. Developing a new vaccine could take six months. Said Mr Cordingley: "Who knows where the virus will be by then?"

S'pore braces for 'visitors'

THE fear may have reached Europe, but Singapore appears safe for now. Although birds from Siberia do fly into Singapore during the migratory season, they are mostly shorebirds, said the National Parks Board. The virus, however, is linked to waterfowl which do not migrate through Singapore, said the Agri-Food & Veterinary Authority (AVA), which now tests migrating birds twice a month instead of once during the migratory season of September to March.

Should the flu virus be detected in these birds, the concerned park or nature reserve may be closed and quarantined. AVA will also increase biosecurity in all local poultry farms, slaughterhouses and bird farms.

Singapore has already acted on poultry farms. "But you can't really control the disease in migratory birds," said WHO's Dr Lee Jong-wook. He praised Singapore's contingency plan. The Government had committed $30 million to drugs, with another $75 million pumped into supporting hospital infection containment capabilities. It covers everything from quarantine to treatment to the handling of the dead.

Singapore has banned the import of live birds, poultry meat and poultry products from countries affected by bird flu. Poultry on Pulau Ubin has also been prohibited.

bird flu facts

What is bird flu? Infection caused by bird influenza viruses. Wild birds, primarily ducks, carry the viruses in their intestines but rarely get sick from them. However, bird flu is very contagious and can kill low-resistant domesticated birds within hours. Bird flu viruses do not usually infect humans but several cases have occurred since 1997.

How are bird flu viruses different from human flu viruses? There are 3 types of flu viruses A, B and C. Wild fowls host type A flu viruses that can also infect people, pigs, horses and other animals. Types B and C viruses infect humans. Bird flu viruses like the H5N1, are named after different combinations of surface proteins called hemagglutinin (HA) and neuraminidase (NA). There are 15 different HA subtypes and 9 different NA subtypes. Until now, there have been only three known subtypes that infect humans H1N1, H1N2 and H3N2.

How do bird flu viruses infect humans? Bird flu viruses are constantly changing, and they might adapt over time to infect humans who come into contact with infected poultry or contaminated surfaces. Studies suggest that a few cases of human-to-human spread of the H5N1 have occurred. This is worrying because we have little immunity against such viruses.

What are the symptoms of bird flu in humans? Symptoms range from fever, cough, sore throat and muscle aches to eye infections, pneumonia, severe respiratory diseases and other life-threatening complications. Bird flu viruses can become resistant to drugs and there is currently no protective vaccine available.

A disturbing threat

If the H5N1 virus were able to infect people and spread easily from person to person, an influenza pandemic could happen. The first recorded flu pandemic occurred in 1580. In 1918, virus H1N1 caused the "Spanish Flu" that killed more than 40 million. In 1957, virus H2N2 caused an Asian flu pandemic that claimed 2 million human lives. In 1968, the Hong Kong flu pandemic, brought on by the H3N2 virus, killed a million. Both H2N2 and H3N2 are likely to have arisen from the exchange of genes between bird and human flu viruses, possibly following simultaneous infections in a person.

Last August, Chinese scientists report H5N1 avian flu infection in pigs, raising fresh concerns that the virus could exchange genes with human flu strains in this "mixing vessel".

The Bird flu trail

After first showing up in 1997 in a three-year-old Hong Kong boy, who had been around sick chickens before he died, the H5N1 virus has done its rounds of Asia and is now spreading its wings. It was detected in Siberia in July and has now been found in Turkey and possibly Romania.

1. May 1997: Bird flu virus H5N1 is isolated for the first time from a human patient in Hong Kong. The virus infects 18 others who were in close contact with poultry. Six die. Fortunately the virus does not spread from person to person. Within three days, Hong Kong's entire chicken population is slaughtered to prevent further outbreaks.

Feb 2003: Alarm bells ring again when the bird virus H5N1 infects two people in Hong Kong. One dies.

2. Feb 2003: Outbreaks of chicken flu occur in The Netherlands due to the H7N7 bird flu virus. By April the virus has spread to nearly 800 poultry farms and resulted in the culling of almost 11 million chickens. The virus infects 83 people, causing conjunctivitis and flu-like symptoms, and kills one man. The drug Tamiflu helps protect people against further spread of the virus.

3. Dec 2003: South Korea has its first outbreak of bird flu in chickens, caused by H5N1.

Jan 2004: Japan has the first outbreak of bird influenza (H5N1) since 1925. This strain of the virus wreaks havoc among poultry in Thailand, Vietnam, Japan and South Korea, and a duck farm in China.

March 2005: By now, bird flu has spread to 10 countries and killed around 50 million chickens.

4. Jan 2004: WHO confirms H5N1 infection in 11 people in Thailand and Vietnam. Eight of them die.

Aug 2004: H5N1 is reported to have killed three more people in Vietnam.

Dec 2004: WHO reports another human case of H5N1 in Vietnam.

Jan/Feb 2005: 13 additional cases of bird flu reported in Vietnam since December 2004. 12 die. First report of a bird flu case from Cambodia.

March 2005: 15 additional cases of H5N1 infection in Vietnam, with one additional case in Cambodia.

5. 6 April 2004: Bird flu virus H7N3 confirmed in two poultry workers in British Columbia who develop flu-like symptoms.

6. May 2005: Rumours of human deaths in China from H5N1 remain unconfirmed, while the virus has killed more than 1000 migratory birds. Indonesia's government confirms reports of H5N1 infection in pigs.

June 2005: Indonesia confirms a man exposed to sick chickens has been infected with a deadly strain of avian flu virus. The farm labourer shows no symptoms, but his blood carries antibodies to the H5N1 strain.

July 2005: The Philippines, thus far unaffected by bird flu, reports its first case in a duck in a town north of Manila. The virus is not H5N1.

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