Over the past 60 years, the influenza virus has continued to drift and shift. In 1968, a shift once again caused a pandemic. In 1976 and 2009, concerns that the virus had shifted led to [fears that a new pandemic loomed]. But Americans were lucky once again.

As bird flu spreads in the United States, are there are any risks of the virus from drinking milk or eating eggs? Here's what you need to know, according to experts.