Right now, you may be hearing a lot about avian flu – or “bird flu” – in the media.

There are actually many kinds of flu that can infect birds – wild birds as well as domestic birds, like chickens or turkeys. But recently, health officials have been especially concerned about one particular strain of bird flu. Known as “H5N1,” it can make people – as well as birds – severely ill.

How does bird flu affect people?

This form of avian flu is very dangerous for people who get it. About 150 people in Asia have come down with H5N1 flu over the last couple of years, and about half of them have died.

However, it’s very hard – and maybe even impossible – for people to get H5N1 bird flu from each other. You get it from direct contact with birds or their droppings. That’s why there have been so few human cases.

If you only get it from birds, why is everyone so concerned?

Health officials are concerned that H5N1 could develop the ability to spread easily from one person to another. If that happens, the result could be a “pandemic” – a very dangerous, worldwide outbreak of flu, with widespread illness and loss of life.

H5N1 may develop the ability to cause a pandemic – or it may not. But influenza pandemics have occurred periodically throughout human history – including a major pandemic in 1918, and smaller pandemics in 1957 and 1968. Health officials believe that another pandemic is likely to occur eventually, although it could be caused by a strain of the flu virus other than H5N1.