Scientists have discovered how bird flu adapts in patients, offering a new way to monitor the disease and prevent a pandemic, according to research in the Journal of General Virology.

A pandemic occurs when a flu virus undergoes a dramatic genetic shift and emerges as a novel strain to which no one has immunity. The one in 1918 killed an estimated 50 million people.

The media frenzy over bird flu has receded, but the threat of a global epidemic still looms large.