Health: Doctors alerted to risk from killer flu

In the first sign of concern in Britain over the outbreak of avian flu in Hong Kong, the Government has written to all doctors alerting them to the events. Jeremy Laurance, Health Editor, explains why the threat is real.

Britain must be prepared to deal with a possible flu pandemic, the Government's Chief Medical Officer said yesterday.

Although there was no evidence yet that one was imminent it was necessary to alert medical authorities to the potential risk in the light of the outbreak of cases of a new flu strain in Hong Kong, Sir Kenneth Calman said.

In a letter to all doctors, Sir Kenneth describes the recent events in Hong Kong, where nine cases of infection with avian flu never before seen in humans have been identified, and reminds doctors that a pandemic plan drawn up by the Department of Health and published last March is in place.

He said: "This is not a panic measure. There have been no cases of Hong Kong flu here. But it seemed sensible to allow all GPs to have information about it. It is a way of being prepared for this kind of thing. "

Sir Kenneth added that all necessary preparations were in place should there be an outbreak of the flu strain here.

Concern about the outbreak in Hong Kong has risen since it was confirmed that the latest victims, a boy and girl aged two and three, are cousins of a five-year-old girl who had earlier contracted the illness.

This is the first evidence that the illness, which originated in chickens and has jumped to humans, can spread from person to person. All previous cases have been caught directly from chickens.

If confirmed, evidence of the infection spreading from person to person would increase the threat of the illness spreading round the world causing a pandemic. The flu strain involved, H5N1, is completely different from any that has been seen in humans before and there would be little or no resistance to it.

However, experience up to now suggests that its capacity to spread from person to person is limited at best. If that proves to be the case the risk of a pandemic is greatly reduced.

Although flu is normally a mild illness, every couple of decades the virus undergoes a mutation producing a strain to which no one has immunitye. Three previous flu pandemics have occurred this century, killing millions around the globe, and all involved avian flu viruses that originated in birds. The 1918 pandemic, in which 20 million people died - more than during the First World War - was followed by pandemics in 1957 and 1968. Virologists say the next one is overdue.

The seriousness of the threat is underlined by the Department of Health's decision to issue guidance to health authorities and trusts last March instructing them how to prepare for the next pandemic.

The document, Multiphase Contingency Plan for Pandemic Influenza, says the aim is to reduce death and disease and enable the NHS "to cope with large numbers of people ill and dying". It says all non-urgent admissions to hospitals may have to be cancelled and hospital plans "must include mortuary arrangements in the event of a large number of deaths".

Flu viruses have long been known to mutate in animals - particularly pigs - from which they can jump to humans. Previous pandemics have originated in the Far East where rural populations live in close proximity with animals.