The virus known as influenza is a quick-change artist that eludes the human immune response by mutating so quickly that it soon becomes unrecognizable. Even more dramatic change happens when two different viruses from two different hosts, such as from humans and ducks, get into the same cell. The result is a hybrid virus with completely novel antigens. This can spread like a windblown forest fire through the world's human population, which has little or no immune resistance to the new form. This scenario, called antigenic shift, can give rise to a pandemic. Examples of antigenic shift include the periodic outbreaks of Asian flu and Hong Kong flu during the 20th century and, more recently, H1N1 flu and bird flu in humans.
The virus known as influenza is a quick-change artist that eludes
the human immune response by mutating so quickly that it soon
becomes unrecognizable. Even more dramatic change happens when two
different viruses from two different hosts,...
More
Dr. Anthony Komaroff answered:The virus known as influenza is a quick-change artist that eludes the human immune response by mutating so quickly that it soon becomes unrecognizable. Even more dramatic change happens when two different viruses from two different hosts, such as from humans and ducks, get into the same cell. The result is a hybrid virus with completely novel antigens. This can spread like a windblown forest fire through the world's human population, which has little or no immune resistance to the new form. This scenario, called antigenic shift, can give rise to a pandemic. Examples of antigenic shift include the periodic outbreaks of Asian flu and Hong Kong flu during the 20th century and, more recently, H1N1 flu and bird flu in humans.The virus known as influenza is a quick-change artist that eludes the human immune response by mutating so quickly that it soon becomes unrecognizable. Even more dramatic change happens when two different viruses from two different hosts,... More
