With bird flu on the horizon, this is the time to learn about it. I'll try to explain it in simple terms. You can learn more at www.cdc.gov/flu/avian/.
What is bird flu, or avian influenza? First of all, it is important to know that there are different strains of flu in the world. There are the ones that infect humans, the ones that infect pigs, the ones that infect horses, and the ones that infect birds, to name a few.
The type that infects birds, the scary one we are talking about, is called H5N1. It right now is causing a bird flu outbreak in Asia. A lot of birds are dying, and possibly passing on the flu in a rare case of transmission to humans.
Normally, viruses from birds don't infect humans. They can only infect birds because birds have right proteins on their cells to let the virus enter. Humans don't. The way that the virus could infect humans is to mutate and somehow find a way to enter human cells. Even then, it has to make the human sick enough (at least a cold) to pass on the virus to other humans. Only then will there be an epidemic.
Why is H5N1 killing all of these birds NOW? H5N1 is different from other bird flu strains because it has changed. While normal bird flu only infects the intestines and the airways of birds, H5N1 can infect intestines, eyes, airways, and many other organs. This means that rather than just a normal flu-like symptom or ruffling of feathers in birds, the birds can die.
What will happen if bird flu gets into humans? Infection of humans could mean you get just a plain old flu, or something more serious like an airway attack, or even death. Because humans have never seen a virus like this before (Our usual influenza is really different from bird flu), our immune systems don't know how to attack the virus to stop it. So it could possibly have a stronger effect.
What about a vaccine? Groups are now working on trying to get medicines and vaccines for H5N1, in case of an outbreak. The vaccines that are being tried right now require a lot more killed virus than the normal flu vaccine. When one is developed, people may need to get more than one shot to prevent disease. Vaccines are now in trials.
How can we prevent it? Stay away from birds, if you can! Don't eat raw eggs or uncooked poultry. Avoid travel to places that have known outbreaks of avian flu, or at least stay away from poultry farms and any contact with animals there. And when any flu vaccine becomes available - get it! If you get any flu-like symptoms it's probably just the regular flu, so wash your hands frequently, see your doctor, and get plenty of rest. Don't cough on anybody!
