What is the present public health concern about avian flu?
Scientists know that avian and human influenza viruses can exchange genes when a person is infected with viruses from both species at the same time. This process of gene swapping inside the human body can give rise to a completely new subtype of the influenza virus. This new virus might then be able to infect humans and spread from person to person. Few, if any, humans would have natural immunity to this new virus. In addition, the existing vaccines would not be effective against a completely new influenza virus. Scientists are concerned that the lack of natural immunity and the lack of effective vaccines against a new virus could lead to a pandemic (worldwide epidemic). National and international agencies are taking steps for dealing with this possibility.
