The bird fluoutbreak among dairy cowscontinues to generate alarm, despite reassuring news that pasteurized milk is unlikely to infect anyone with H5N1. Scientists can't stop worrying about a nightmare scenario: that the virus will get into pigs and, from there, spark a human pandemic.
Pigs are capable of harbouring both human flu and bird flu, allowing the viruses to mix and match parts of their genetic material. Pigs are the perfect vessels through which an even more virulent strain could emerge.
H5N1 also has a high fatality rate of 52% in humans.