Imagine that the year is 1919. You have just survived one of the greatest infectious disease disasters
of the 20th century. Twenty million people world-wide (500,000 in the United States) have died from
a brutal disease that causes their lungs to fill with fluid and their bloodstream to be filled with deadly toxins. A large
number of these people were young adults with no previous health problems.
The disease responsible is influenza : the common flu.
An outbreak such as the one in 1918 could easily occur again if the influenza virus were to undergo a
process known as "antigenic shift".
The information below and on following pages describes antigenic shift in influenza and its consequences for public health.