Panic rather than pandemic

IN ordinary times, the deaths of six swans at a nature reserve would have gone virtually unnoticed. Even the discovery of the bodies of another ten birds at a nearby pond would normally have caused barely a ripple.

But these are not ordinary times. The world is in the grip of anxiety over a menace which is said to strike without warning and kill without mercy. The shadow of bird flu is hovering.

So far, it has caused more panic than pandemic. There are reports of patients ringing up their GPs demanding vaccination, even though no available vaccine would combat the virus. More selfless souls have called radio phone-ins urging that any vaccines be given to those younger and fitter than themselves.

Those treatments which are available are in demand. The makers of Tamiflu, an anti-viral drug which could lessen the severity and duration of an attack although does not provide immunity, have reported a surge in inquiries from individuals. A full five-day course of pills on eBay reached double its normal price before the sale was pulled.

The reason for the unease is clear: bird flu is considered the most likely candidate for the next pandemic, on the scale of the Spanish flu outbreak of 1918. Around 50 million people died then, more lives than were lost in the trenches of the First World War. A similar death rate now would kill around 150 million, 2.5 per cent of the world's population.

So far the H5N1 virus - named after the proteins on its surface - has proved particularly virulent. Out of the 119 confirmed cases, 62 have died, although it may be that some of those infected recovered without knowing what they had and the true survival rate is much higher.

And unlike many other flu viruses, but in common with Spanish flu, H5N1 is fatal not just to the old and the vulnerable. By attacking deep within the lung, the virus provokes an overwhelming immune response that sees the victim's lungs filled with fluid, meaning youth and fitness is no protection.

Although humans have caught the virus from live birds, as yet it has spread between humans in only a handful of cases. But the fear is that if bird flu combines with a human flu, it could produce a new strain which is both highly infectious and deadly. Pigs, which are susceptible to both human and bird viruses, have been earmarked as the most likely mixing vessel for such a new variation.

It is this which lies behind efforts to step up preparations for a possible pandemic, given additional momentum with the news yesterday that the H5N1 strain had been found in the bodies of the 16 swans discovered in eastern Croatia. Two parrots in quarantine in the UK had already tested positive for H5N1.

On Tuesday, the EU announced it was to ban the import of live birds, although this does not cover poultry, and yesterday an international meeting of health ministers recommended that more resources be put into developing a vaccine, although work can only really get underway once the new strain has emerged.

The pigeon and poultry sections of this weekend's Countryside Live Food and Farming Fair in Harrogate this week became the first event to be cancelled due to fears of bird flu, and Environment Secretary Margaret Beckett yesterday announced that details of new measures to try and prevent the spread of the virus would be announced within days. These are expected to include establishing a register of commercial poultry producers and the possibility of moving all poultry indoors, a precaution already taken in Holland.

Even if a pandemic does not emerge, businesses could be hit by a collapse in consumer confidence. The European Food Safety Authority has reiterated its advice that both poultry and eggs are safe to eat, and that consumers need only take the same precautions used to guard against diseases such as salmonella, particularly over ensuring the food is cooked properly. But earlier this month Northern Foods announced that some of its products may become more expensive as anxiety over bird flu pushed up the price of chicken. Areas where bird flu has been reported could also see a loss of tourist trade, as happened during the foot-and-mouth outbreak of 2001.

After initial accusations of complacency, the Department of Health launched a programme to stockpile Tamiflu. So far, 2.5 million courses have been bought, with more arriving at the rate of 800,000 a month to a total of 14.5 million. The UK has also planned to buy enough vaccine for the entire population.

In France, the government has ordered 200 million protective masks, and health checks at airports have been stepped up. Greece, which has had a case of bird flu, has banned the export of all live birds and poultry products from the affected islands.

But there are reports that H5N1 may be developing a resistance to Tamiflu, and experts are divided on how effective stockpiling the drug could be. Individuals are being discouraged from purchasing their own supplies, on the grounds this could limit the amount available for governments, and that taking it indiscriminately may encourage the virus to become resistant.

So far, efforts to avert a pandemic are concentrated on early identification of an outbreak and then quickly isolating the affected area to prevent it from spreading. Unlike in 1918, widespread air travel means a virus can cover the globe within days, as happened during the Sars outbreak of 2002. But improved communications means it should be easier to spot its emergence and to move to contain it.

For microbiologists, the question has long been not if there will be another pandemic, but when, and so far H5N1 seems the most likely candidate. There is still no certainty, however, that if and when H5N1 mutates into a form which is readily passed from human to human it will retain its high mortality rate: the new virus could be much milder.

But if a deadly strain does emerge, the key to reducing its impact is likely to lie in the speed with which an effective vaccine can be produced. The best estimate is several months, although work is already underway for a vaccine for the virus now in circulation. Even if this does not immunise against the new strain, it could provide a basis to work from, bringing a new vaccine a step closer.

For all the talk of pandemics, and for all the anxious calls to GPs' surgeries, there is still no sign that a flu strain has emerged which could provide a threat on the scale of Spanish flu. For now, while precautions are being put in place, there is more reason to be watchful than to panic.