The Looming Threat of a Bird Flu Pandemic.
Experts warn that bird flu is just four mutations away from causing a pandemic in humans. These mutations include the ability to survive in the air, optimizing itself to infect human cells, and matching itself to better connect to human viruses. The virus needs to undergo four mutations, including changes to the hemagglutinin and RNA, to bypass human defenses and start a deadly pandemic. While the virus remains a threat, it could take decades before even a single one of the changes is made.