What you need to know: There is no pandemic influenza in the world today, but...

Over the last couple of years, a small number of people in Asia, Africa and Europe have become ill with a strain of flu that normally affects birds—the H5N1 virus. There are no cases of this bird flu in birds or humans in the United States at this time.

Most of these people have gotten the illness from birds—not from other people. For those who have contracted this flu, the illness appears to be severe with a high death rate.

There is concern that H5N1 or another strain of flu virus could cause a pandemic—a dangerous global outbreak of disease. A global outbreak will only happen if this flu virus changes so that people can easily get it from each other, not just from birds. That has not happened yet, but health officials are concerned that such a change is possible.

It is important to be prepared and the more we plan now, the better off we will be in the future. Planning for a pandemic also helps us prepare for the annual flu season and other public health emergencies and disasters.

"Flu" is short for influenza, a contagious respiratory illness caused by viruses. These viruses can cause mild to severe illness, depending on the strain of the virus and the person's ability to fight it off.