How is an avian influenza outbreak among birds different than an influenza pandemic?
An influenza outbreak among birds occurs when the virus causes serious illness or death and is spread from bird to bird. If the avian virus is contagious to people, then humans may inadvertently become infected due to exposure to sick birds. An influenza pandemic can occur when the avian virus infecting humans changes and then spreads easily from person to person. This results in an epidemic over a wide geographical area, usually over more than one continent, or a pandemic.
