The London Times has an account of how a
software glitch provided epidemiologists a glimpse into how people would
respond to an epidemic.
And it all happened by accident. In September 2005 what was
intended as a minor hindrance for a small group of characters spiralled
beyond the control of program-makers into a full-blown epidemic.
A new villain, a winged serpent called Hakkar, originally designed as a
challenge for only the strongest characters, started transmitting its
"corrupted blood" virus down the ranks until it affected almost every
area and every player in the game.
The scientists were able to monitor how quickly the disease spread and
where to, while assessing the players' individual responses to the
outbreak. The particular features of the game, such as the many hours
players around the world dedicate to it and the emotional investment
they put into their online alter egos, offer scientists a tantalisingly
close match to real social conditions.
As the virus spread, very real challenges emerged, such as the failure
of quarantine measures, further transmission by character's pets and the
existence of "immune" characters, who act as carriers, passing the virus
to others while failing to succumb to symptoms.