An influenza pandemic is a global outbreak of disease that occurs when a new influenza A virus emerges in the human population, causes serious illness, and then spreads easily from person to person worldwide.
Currently, there is concern over the H5N1 Avian Influenza virus which has been endemic to birds in South East Asia for the last 10 years but has recently spread to birds in Europe and Africa. Over 100 people have died from the virus, all of whom had close and prolonged contact with poultry.
Avian (or bird) flu is caused by influenza viruses that occur naturally among wild birds. The H5N1 variant is deadly to domestic fowl and can be transmitted from birds to humans.
Pandemic flu is virulent human flu that causes a global outbreak, or pandemic, of serious illness. Because there is little natural immunity, the disease can spread easily from person to person. Currently, there is no pandemic flu.
It is important to remember that although the H5N1 virus has been transmitted from bird to human, it has not yet demonstrated sustained human to human transmission, one of the critical components to a pandemic influenza.