Bird Flu's Worrisome Signals in Indonesia

Disturbing reports from Indonesia on the bird flu. Investigators are trying to determine whether a series of H5N1-related deaths within families may be signs that the virus has evolved for easier human-to-human transmission.

That ability is the starting gun to a likely pandemic. Once the virus (or any other new strain of influenza) adapts to easy human-to-human transmission, it spreads rapidly among the human population, which has no immunity against the new strain.