Why is avian influenza currently raising concerns?
Influenza viruses can change rapidly. This can cause an outbreak to shift from causing only mild illness in birds to causing rapid high mortality rates. A viral change during the course of an epidemic may also alter which species can be infected by the virus. Avian influenza is currently of concern because of the potential for people to become infected with the H5N1 virus. However, avian influenza will not become widespread in people unless the virus gains the ability to be transmitted from person to person easily. To date, human cases have been traced to close contact between humans and live poultry or ducks.
