On New Year’s Eve, a bus driver in the Chinese city of Shenzhen,
located just across a river from Hong Kong, died from the virus
H5N1, commonly known as bird flu. The news must have unnerved a
lot of people who saw the 2011 hit movie Contagion, in which a
fast-mutating type of bird flu first surfaces near Hong Kong and
ends up wiping out about a quarter of the world’s population
within a matter of months. The fear of pestilence is a valid
one, with deep roots in human history; but it’s a fear
frequently exaggerated and exploited by the media. One rather
fanciful sci-fi theme – of extraterrestrial microbes arriving
via meteorite to wreak havoc upon Earthlings utterly lacking any
resistance to them – launched an extremely lucrative writing
career for the late Michael Crichton with his first best-seller,
The Andromeda Strain. But if some modern scientists are positing
that nucleic acids from other worlds may have laid the
foundation for life on Earth, then isn’t it also possible for a
virus to hitch a ride on a