What there is to know about bird flu

Your bird flu FAQs

Boots WebMD has been in touch with the Department of Health, the World Health Organisation and infectious disease experts to answer your bird flu questions.

What is bird flu?

Bird flu, or avian influenza, is an infectious disease of birds caused by type-A strains of the influenza virus. Bird flu epidemics have occurred worldwide.

Migratory waterfowl - most notably wild ducks and swans - are the natural reservoir of bird flu viruses. It's known that infection can spread from wild fowl to domestic poultry, including chickens and turkeys, and then to humans. Live bird markets have also played an important role in the spread of epidemics.

The most recent bird flu epidemic in southeast Asia caused by the H5N1 strain is the largest ever recorded. Because the disease has spread to wild birds - including ducks, which carry the virus without getting sick - it will be hard, if not impossible, to eradicate the virus. Making matters worse, the virus has already changed to be able to infect and kill mammals such as tigers, domestic cats and pigs.

How do humans get bird flu?

People catch bird flu by sustained contact with infected birds or bird droppings. People don't catch the virus from eating fully cooked chicken or eggs. There have been a few cases where one infected person caught the bird flu virus from another person, but only after close personal contact.

Can I catch bird flu from another person?

As long as the bird flu virus doesn't mutate into a human flu virus, it won't spread far in people. But sometimes - after close personal contact - a person who gets bird flu does infect another person. It's not clear exactly how this happens. However, casual contact does not seem to be involved.

What are the symptoms of bird flu in humans?

Humans who catch bird flu from chickens start out with normal mild flu-like symptoms. With the H5N1 strain, however, symptoms are more severe and may progress to severe respiratory disease that has been fatal in a high percentage of cases.

What's the worst that could happen?

If a person, or a susceptible animal, gets infected with bird flu and human flu at the same time, the bird and human flu viruses could swap genes. If the new virus is as lethal as bird flu affecting poultry, and as contagious as human flu, it would be serious.

It's also possible that bird flu could “learn” to infect humans even if it doesn't recombine with a human flu virus.

Even if it's a relatively mild new flu virus, it could spread rapidly across the globe. That's because most humans would have no immunity to the new kind of flu. During the 20th century, this happened three times.

Is there a vaccine?

Yes, a vaccine has been developed and in the UK supplies have been stock-piled.

Is there a treatment?

The bad news is that the current bird flu strain is immune to older flu drugs. However, the drug remains sensitive to the newer anti-viral drugs. In response to 2005's Fujian flu epidemic, some countries began making plans to stockpile anti-viral drugs, including the UK.