- The Washington Times - Saturday, August 27, 2005

LONDON - When doctors in 1997 announced the deaths of some people in Hong Kong from a new form of flu, it made few headlines. Something called avian influenza A (H5N1) apparently had spread from chickens to humans in the city’s teeming back streets, infecting 18 persons and killing six before vanishing. The jump across the species barrier was a surprise, but the outbreak seemed like a storm in a distant teacup.

But now the same virus has turned up at the threshold of Europe. Earlier this month, Russian scientists revealed that thousands of domestic birds around the Chelyabinsk region of the Ural Mountains had died after contracting H5N1, which apparently had been transported there by migrating birds.

“Wild birds that have migratory pathways over Europe and the UK will become infected. It is inevitable that bird flu will be carried to this country by migrating birds,” Dr. Bob McCracken, president of the British Veterinary Association, said Thursday.

So far, the strain has failed to repeat the feat it first achieved in Hong Kong and find a way of infecting humans, but many analysts think that it is only a matter of time before it succeeds.

Since the Hong Kong outbreak, the H5N1 virus has spread across Asia and infected another 100 or so people, killing around half of them. So far, all the victims appear to have contracted the virus after direct exposure to birds.

Yet, each time the virus succeeds in infecting humans, it increases the chances of triggering the nightmare scenario: human-to-human transmission. The consequences could hardly be more worrying. Some scientists already are drawing parallels with the so-called Spanish flu outbreak of 1918, when another bird-flu virus — code-named H1N1 — hit the right genetic combination needed to trigger human-to-human transmission. The resulting pandemic led to at least 20 million deaths, double the number of people killed in World War I.

“The population is higher now, so we could be talking about 100 million deaths or more,” said Neil Ferguson, a specialist on virus epidemics at Imperial College in London. “The 1918 scenario is within what people should be planning for.”

Mr. Ferguson said such an epidemic is most likely to start, after the H5N1 virus infects someone already harboring standard human flu.

“Then the two viruses can recombine to produce a type capable of human-to-human transmission,” he said. “We’re worried because this bird virus is so lethal. It kills 50 percent of those infected at the moment, though that could change, once it gets into humans.”

By comparison, Mr. Ferguson said, the virus responsible for the 1918 pandemic killed only a few percent of those it infected. Small wonder, then, that alarm bells are ringing.

The World Health Organization (WHO) has made clear its concern about the spread of H5N1 beyond Southeast Asia. It called for close surveillance of the situation in Russia, and it checks on respiratory patients who could have been exposed to sick birds.

It has begun negotiations to stockpile anti-viral drugs, which both reduce the symptoms of those already infected and provide some protection against the virus.

Many national governments are drawing up strategies to combat H5N1. In Britain, the Department of Health has made contingency plans for dealing with an outbreak and has set aside $360 million to buy enough anti-viral drugs for a quarter of the population.

General practitioners are being sent information packs about how to deal with an outbreak and guidance for patients. There are no plans for a mass vaccination campaign, however. Officials point out that any vaccine based on the current strain of H5N1 could prove useless against a human-to-human transmission.

Because of the efforts to avert a pandemic, many specialists remain confident about our ability to cope with the threat. They point out that the virus is still confined to the bird population, making control of an outbreak relatively simple. As soon as tests confirm the presence of the virus in a flock, the plan of action is dramatic and Draconian: rapid and massive destruction.

The strategy stopped the original Hong Kong outbreak in 1997. It also halted an outbreak of the H7N7 bird flu, which also infected humans, in Holland in 2003.

“At the current state of play, on a scale of one to 10, I’d put the risk of a pandemic pretty low down, at around 3 to 4,” said Nigel Horrox, the president of the British Veterinary Poultry Association and an independent poultry veterinary surgeon who regularly works in Asia. “Some context is also needed here. There have been 60 to 70 human deaths out of several billion in Asia. On the Thai Songkran bank holiday, you’ll get many more deaths on Bangkok’s roads in two or three days.”

Simple honesty is considered crucial by many specialists. They point out that the speed of international travel makes any attempt at bureaucratic foot-dragging potentially disastrous.

In November 2002, Guangdong province in China was hit by a new type of virus called SARS, which caused pneumonia-like symptoms and killed one in 10 of those infected. Yet Chinese officials attempted to cover up the outbreak, informing the WHO only in February the following year.

By then, the virus had spread to Hong Kong and Vietnam. It then claimed almost 800 lives in a dozen countries, from Canada to the Philippines. If bird-culling policies fail to stop the H5N1 virus, Mr. Ferguson said, it could spread to every continent in the world within eight weeks.

Even so, prompt action could stop the virus from triggering a pandemic. In research published this month in the journal Nature, Mr. Ferguson and colleagues showed that the outbreak could be contained if the first few dozen people affected were identified and about 20,000 of those closest to them were treated with anti-viral drugs.

He said: “Given that the potential consequences are so severe, I’m trying to persuade the WHO and governments to put more money into containment.”

As scientists and health officials race to cover all bases, some specialists are drawing comfort from events so far.

“If the doomsday scenario is realistic, why hasn’t it happened yet?” Mr. Horrox asked. “This virus has had lots of opportunities across Asia to mutate but hasn’t, so the probability must really be very low.”

Ultimately, however, no one knows what the tiny packet of genes known as H5N1 will do next. It could fade back into its host population of birds, among which it produces no ill effects. Or it could produce a human pandemic of apocalyptic proportions.

For now, scientists can only hope they are smart enough to deal with whatever their microscopic adversary throws at them.

“I think we’re doing all we can,” Mr. Ferguson said.

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