'Never have so many countries been affected by the avian flu virus'

How many people and countries are now affected?

Worldwide, 76 people have died of the H5N1 strain of avian influenza and the total number of confirmed cases has reached 146 in Vietnam, Thailand, Cambodia, China, Indonesia and now Turkey. Vietnam has the highest number, with 93 cases and 42 deaths. China has reported seven cases and three deaths. Several other countries, such as Russia, Malaysia and Romania have reported outbreaks of influenza in poultry or wild migratory birds, but these nations have so far reported no cases in humans.

Is the current outbreak of the H5N1 strain in poultry unusual?

The World Health Organisation said that never have so many countries been simultaneously affected by a single, highly lethal strain of the virus. The H5N1 strain has proved especially tenacious. Even though millions of birds have been culled in south-east Asia, the virus is now considered endemic in many regions of the affected countries.

What is avian flu and why is this strain so deadly to humans?

The avian flu virus belongs to the same broad group of viruses that cause flu in people. Avian flu viruses do not pass to humans, but occasionally they can and when they do they can cause epidemics.

Is the current outbreak of bird flu a threat to Britain?

So far the H5N1 strain does not appear to pass easily from person to person, which is a necessary prerequisite for a global epidemic or pandemic. The fear, however, is that with many millions of infected birds, and an increasing number of people catching the virus, there is an increasing risk of a more transmissible strain evolving.

How does bird flu spread?

Some waterfowl are thought to carry the virus when migrating and they could infect domestic poultry kept outdoors. Humans can pick up the virus by handling live birds or by coming into contact with bird droppings.