Q&A: The threat from bird flu

A deadly strain of bird flu in migratory birds and domestic poultry in Siberia has triggered fears that Europe could be poised for its own outbreak of a virus that in Asia has devastated poultry stocks and killed 57 people.

Do we need to prepare for a pandemic? How real is the threat? Amid mounting fears about bird flu the FT’s science editor, Clive Cookson, answers your questions.

For FT.com’s special report on bird flu click here

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As the avian virus in wild birds is spreading around the world, its mutation into a human virus and the threat of a global pandemic are becoming more real. Can you please advise if there are any actions that a person can take to minimise the chance of infection.

Len Vindman

Clive Cookson: The chance of being infected directly by a bird is very small, unless you are a poultry worker or farmer.

If the virus mutates to a form that spreads easily between people - and the long-feared pandemic starts - then one of the best ways to avoid infection will be to minimise contact with other humans. But if everyone takes that attitude, all business and social life will come to a halt.

One possible precaution would be to lay in a stock of Tamiflu, Roche’s anti-flu medicine, to take in case the pandemic comes. This would not actually stop infection but would reduce your risk of dying if you start take the drug within two days of symptoms starting. Although Tamiflu is in short supply, it is still possible to obtain if your doctor is prepared to write a private prescription for it. Or you can get hold of it through an internet pharmacy, at a cost of around £50 for a course of treatment (10 capsules).

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Earlier this year our neighbour erected two giant free-range poultry units on top of the hill in front of our house. Consequently we have 12,000 birds ranging to within 100 metres of our home. The prevailing wind blows in our direction so our house and garden is full of flies attracted by the poultry. Having destroyed the value of our property, our peace and our view, does this development also threaten our health more than most people’s?

Anonymous (name provided)

CC: It sounds like a ghastly neighbour but I don’t think you are at extra risk from bird flu as a result of this development. People in Asia who have caught the H5N1 virus from birds have had more direct contact with them than you have. There is no evidence that flies can transmit flu.

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What has changed recently to cause the volume of articles on bird flu to increase, and the health authorities to start issuing information pamphlets to local health authorities? We also hear that the mayor has started ordering vaccines in. Is this an imminent danger?

Leith Assouad

CC: The most important development this year is the establishment of bird flu infection among wild birds - waterfowl in particular. This increases the risk that avian migrations will carry the virus around the world. The more widely it spreads, the greater the chance of it mutating somewhere to a form that transmits easily between people.

Ordering supplies of vaccine and antiviral drugs, or issuing information leaflets to local health authorities makes good sense as a precaution. It doesn’t mean an imminent danger.

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On 20 September we will have our first duck shoot, where maybe 50 wild duck will be shot. Should we take any precautions to protect the dogs, the guns taking part, the game dealers, or the consumers of the game that falls to our guns?

Robert B Christie

Marston Shoot

CC: I think wildfowlers in the UK will be safe for the next month or two. It will take at least that long for the H5N1 avian flu strain to reach here on migrating birds from Asia.

If avian flu does become established in western Europe, there will indeed be a risk to those directly exposed to infected birds. In fact, I would not be surprised if shooting were banned then, as it has been in parts of Russia.

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Is it a sensible idea to buy Tamiflu for my family over the internet?

Neil Gallacher and Mark Wymer

CC: Some people think there’s something rather disreputable or even irresponsible about buying drugs over the internet but in this case I see nothing wrong in it. You may have to pay a high price - it was around £50 per course of 10 Tamiflu capsules last time I looked, while the UK government is reportedly paying around £13 per course for its bulk order of 14.6m courses. The drug has a shelf life of five years in cool dry conditions - it doesn’t need to be stored in a fridge - so, even if the pandemic does not strike, you might be able to use it for ordinary seasonal flu before it expires.

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Do you think the risk of a deadly global human influenza pandemic arising from bird flu has increased, decreased or remained the same over recent weeks?

Alex Erskine

CC: I think the risk has increased because the geographical spread of the H5N1 virus has increased, with its appearance in birds in Russia, Mongolia and Khazakstan. However, there is still no sign of the virus “going human”, i.e. undergoing the dreaded mutation that will allow it to spread easily between people.

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What will happen if the bird flu turns into a pandemic, killing humans within a few months? Do you think that the global community is ready for this? What kind of preventive measures do you recommend to protect public health? I know that the World Health Organisation (WHO) is doing its best. However, many countries do not have the means and scientific base to fight against such an outbreak. Do you think that the next UN Summit could be a good forum to recommend possible global measures to fight this phenomenon?

Ali Murat Ersoy

CC: The global community is a good deal more prepared now than it was a few months ago but I don’t think it has yet done enough. Fortunately, the WHO - or at least the part that deals with infectious diseases - is itself in good shape at the moment, with plenty of excellent, well-motivated doctors and scientists at its disposal. Governments of industrialised nations need to put more resources at the WHO’s disposal. If H5N1 does go human, then a massive crash course of vaccine development will be needed. The vaccines being developed at the moment are based on the avian virus and the human form, if it arises, will be different.

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Now that we are aware of the potential for bird flu to arrive how likely is it that we will see the same levels of infections and fatalities in humans as we saw in Asia? I am also curious to known how we would contract this infection and if it is likely through humans eating poultry?

James Doyle

CC: The headline mortality rate in Asia for people infected with H5N1 is a terrifying 50 per cent but this is probably an overestimate because milder cases are not all being reported. Any mutation that enables the virus to spread readily between people will change the pathology of the disease and, experts say, almost certainly reduce its virulence. But even if it kills 10 per cent of those infected, a pandemic could have a death toll running into hundreds of millions.

While H5N1 is still an avian virus, it is very hard for people to be infected. Direct contact with infected live birds is the most likely route. Cooked poultry is unlikely to be infectious. After it goes human, it could be caught from other people in the same way as ordinary flu.

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An important cause of the spread of the disease out of South-East Asia is the fact that the authorities in affected areas did not immediately disclose the cases or act very fast to contain the disease.

Are we really prepared here in Europe to fight this disease? It will strike this autumn/winter since the migrating birds from Russia will arrive in September/October in the relatively warmer parts of Europe such as Romania, Bulgaria, Greece, Balkans, Italy and Hungary.

If short-sighted economic arguments prevail - such as the cost of medicine - the consequences will be terrible. If our leaders just say (as WHO seems to say ) ‘there is no big danger’ what will be the consequences ?Who is in charge and who is accountable for management of this issue ?

It is clear that now it is a matter of time (i.e. when) and not of probability of occurrence of the disease in the whole Europe and in the Americas.

Dumitru Petre

Bucharest, Romania

CC: Openness and quick response by the authorities are, as you say, absolutely essential. I think the Chinese learned this with SARS, when an attempt to cover up the original outbreak had disastrous consequences, and they are apparently being more open and responsive over bird flu.

If any organisation is in charge, it is the WHO. The organisation has good leadership at the moment and is better prepared than it was five or ten years ago to fight a pandemic.

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My local lunch spot has had a sign up saying that they no longer serve free range chicken due to supply problems. When I asked what this was I was told that their free range chicken (from a UK farm by the way) had bird flu. I understand that chicken kept outside can be infected more easily as they come into contact with other birds. I had no idea that out-breaks were so close to home - do you think there is any truth in this story or perhaps the person I spoke to was misinformed.

Rachel Offord

CC: I think you or the person you talked to were misinformed. And if I am wrong and bird flu is in the UK, then it is certainly one of the milder strains of the virus. I don’t think an outbreak of the dreaded H5N1 here would or could have been hushed up.

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If the virus mutates and a human flu outbreak begins, what it the understanding of the role airlines might play in spreading the disease? Is it feasible to ground airlines to stop the spread of a human flu virus? If not, wouldn’t a new pandemic be completely different from previous ones in the rate it spreads around the world.

George Mann

CC: You are right in suggesting that international air travel would spread the disease very rapidly around the world. But any action to prevent this happening by grounding airlines would have a catastrophic effect on the global economy. In fact, if SARS is anything to go by, most people would quickly chose to stop flying to infected areas. Some flights would be necessary, however, to maintain essential supplies.

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A pandemic would hit travel and tourism sectors hard. But what companies/sectors might benefit? How do the survival rates compare for H5N1, SARS and some other virulent flus? Why did the 1918 pandemic kill disproportionate numbers of 20-50 year-olds and apparently fewer pensioners? Reporting anomaly, or quirk of infection networks? Would a vaccine materially reduce disruption and death in practice, or just be a drop in the ocean? How long would it take to be able to vaccinate the whole UK population?

William McDonnell

CC: It’s hard to think of any sectors that would benefit if the whole global economy took a catastrophic hit from a severe pandemic. If SARS cost Asia and Canada an estimated $40bn in 2003, then a flu pandemic would cost many trillions of dollars - and we’d all be losers, even if we lived to tell the tale. But I suppose one company that might benefit is Roche, manufacturer of Tamiflu.

The survival rate for H5N1 caught directly from birds is only 50 per cent but a form of the virus that spread between people would almost certainly be less virulent. SARS and the 1918 Spanish flu had a mortality rate of 10 per cent or less.

No one really knows why the 1918 pandemic hit young adults so hard. It may be that some older people had residual immunity from related flu viruses that circulated in the 19th century and then died out.

Vaccination would buy time but until the pandemic starts we won’t be able to prepare a vaccine that is well matched for the human form of the virus. At the beginning we’d have to use poorly matched vaccine based on avian flu, though this would probably offer some protection and buy some time.

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What is the role of the World Health Organisation in terms of forecasting crises? Does it have the resources, expertise, and experience to deserve the credibility which it appears to have in making pandemic predictions?

Benedict E. DeDominicis

The American University in Bulgaria

CC: The WHO is the lead UN agency in dealing with human infectious disease crises (the Food and Agriculture Agency takes the lead on animal diseases and is therefore closely involved in fighting flu in poultry). As I’ve indicated in earlier answers, I have great respect for the WHO’s expertise and experience and I hope the world’s governments will give it the resources it needs.

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To what extent do you think bird flu would shut down economic and social activity in the UK, if the virus did pass from human to human? Given the fact that it can move through the same area (or home or office) more than once, I would have thought the economic and social implications are rather serious?

Bob Kahn

CC: The economic and social implications would indeed be extremely serious, not just for Britain but for the world. If the worst happened, most people would want to stay at home with their families to minimise the risks of infection. But who would then maintain essential public services? Some degree of compulsion might be needed, though essential workers would presumably have first call on available stocks of vaccine and antiviral drugs.

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Do we understand the mode of transmission for the bird flu? Is it airborne or does infection take place via a droplet mechanism?

KOMalley

CC:Certain birds, particularly waterfowl, act as hosts for flu viruses which they carry in their intestines. Infected birds shed virus in saliva, nasal secretions and - most importantly - their faeces. Droppings (rather than droplets) are the main way in which avian flu spreads between birds.

However, flu viruses spread between people mainly in respiratory droplets caused by coughing and sneezing. They usually move directly from person to person in this way, though sometimes people become infected by touching something with flu virus on it and then touching their mouth or nose.

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Is it possible that the avian bird flu will only affect poultry or is its mutation into human influenza now an inevitability?

Charlotte Cassady

London

CC: No, it is far from inevitable that the H5N1 strain of bird flu will go human. On the basis of past flu pandemics, virologists expect another one to occur sooner or later. All pandemics have resulted from the mutation of a bird or animal flu virus into a form that transmits early between people. Although H5N1 is the most likely candidate for the next one, because it is spreading so widely and it is so lethal when it infects humans, the virus may not undergo that crucial genetic change. I have not met a virologist who is willing to estimate the probability of this happening.