Avian Flu
Geoffrey Lean and Severin Carrell report in the Independent about the virus, which has just reached Europe:

If, as the World Health Organisation (WHO) now believes is inevitable, bird flu turns into a human pandemic, killing many millions, the tragic tale of Sakuntala and her mother - officially reported earlier this year in The New England Journal of Medicine - will go down as the moment that one of the greatest catastrophes to hit the world began.

The Journal called the story an "unprecedented warning", and said that "all prerequisites for the start of a pandemic have been met save one" - the virus acquiring the ability to spread rapidly from person to person. Professor John Oxford, of Queen Mary, University of London, says: "It sends a shiver down my spine."

Pandemics are quantum leaps in the development of flu. Normally an existing flu virus, which has been around for decades, undergoes a slight shift, enabling it to infect some people who have built up immunity from previous bouts of the disease.

But every so often, about three or four times a century, an entirely new one arrives. No one has any natural protection against it, and so - once it has developed the ability to spread between people - it is free to commit mass slaughter. So far as we know, the virus always originates in wild birds, and has come out of Asia.

Experts believe this is about to happen again. They cannot say when the bird flu virus will adapt to become extremely infectious to humans, but they say it will do so. The WHO warns that "the world is now in the gravest possible danger of a pandemic".

The latest potential outbreak goes back to 1997, when the virus first appeared in Hong Kong, infecting 18 people. The authorities reacted with admirable vigour, slaughtering all the area's 1.5 million poultry in just three days, and it seemed to disappear. But nearly two years ago it reappeared in South Korea, and by early this year had spread to eight eastern Asian countries. Slaughtering 150 million birds throughout the region has failed to halt the disease, and so far about 120 people are known to have caught it. Half of them have died - an extraordinarily high mortality rate.

Shigeru Omi, the WHO's director in the area, says: "All attempts to bring it under control in South-east Asia have failed."

Now it is spreading around the world. On Thursday, scientists at the Veterinary Laboratories Agency in Weybridge, Surrey, confirmed that tests showed poultry in Anatolia, in Turkey, had the disease. And yesterday, the Romanian government announced that it had been found in its country too.

The crucial event in this spread took place at the massive Qinghai Lake, high in the mountains of north-western China, which is a summer hub for migrating birds from all over Asia. Thousands of wild birds died from the virus there this summer, and in August infected survivors began fanning out towards their winter quarters.

A trail of infected poultry farms followed their migration route across Siberia, and has now reached Europe. It is still largely a bird disease, with only rare cases of humans catching it. But experts warn that it is only a matter of time before the critical mutation that would spark a devastating human pandemic takes place. This month, Sir Liam Donaldson, the Government's Chief Medical Officer, warned that it was a "biological inevitability" it would seriously affect the health of people in Britain. Unofficially, the Government is preparing for up to 750,000 deaths.

One of the preventive measures, in the absence of a vaccine against the virus, or enough Tamiflu to minimize its effects, is stocking up on food and water so you won't have to leave the house. Then there are the 3M P100 and N100 masks, which last for 150 hours. In the absence of one of those, you're supposed to cover your mouth with a cloth.