Since the discovery and rapid spread of HIV, epidemiologists -- people who study the spread of infectious diseases -- have been investigating its movement throughout the world. Epidemiologists create models to simulate the spread of disease, and predict how a given disease will spread. They take a wide array of factors into account -- everything from the way a disease spreads to how quickly infected airplane passengers would carry the bug around the world.
But there is one distinct problem that epidemiologists have always encountered in their models: They are merely predictions. Since they can't release infectious diseases into human populations and chart how they spread, the models must be built on information from past epidemics and subjective interviews. Epidemiologists recently identified another tool that had previously been unconsidered.
In 2005, Blizzard Entertainment, developers of the online game "World of Warcraft," created a new foe as a way to test their best players. One of his attacks was to cast a spell called "corrupted blood" -- a virtual virus [source: Wired]. Characters carried the infection from the remote locations where the battles were fought to populated towns and cities. Here the virus quickly spread beyond the creators' intentions and soon became a plague, killing many weaker characters. Eventually, the developers "cured" the disease. It became a bad memory among players, and mostly went unnoticed among those who don't play the game.
But it didn't escape the attention of some in the medical field. Rutgers University epidemiologists Nina Fefferman and Eric Longren realized that the data collected and kept by the game's developers during the plague could help to build better, more detailed epidemiological models.
The pair studied the reactions to the plague among "World of Warcraft" players, and what they found surprised them. Much of the behavior of the virtual characters (controlled by real people) was exactly like the way people behave toward disease outbreaks in the real world. Some listened to the developers' alerts to stay away from infected areas, as epidemiologists predict would happen with a real plague. But Fefferman and Longren were surprised to find that other people went out of their way to investigate the disease, putting their characters in danger to satisfy their curiosity.
They also found that some people with infected characters were determined to take as many people down with them as they could. They purposely infected others, behavior that has been seen by a few humans in real life. More players, however, put their characters' lives in danger to help others: Those with healing powers sought out infected characters in an attempt to cure them.
By studying the "World of Warcraft" plague of 2005, Fefferman and Longren were able to confirm some widely held epidemiological predictions. Other factors, such as the curiosity that compelled some players to put their characters at risk, show gaps in current disease-prediction models that can be improved upon.
Researchers realize that "World of Warcraft" doesn't provide a complete picture. To begin with, the players' behavior was based on the loss of their characters' lives, not their own, which could affect their actions. Nonetheless, studying virtual worlds may still provide valuable information to help epidemiologists expand their current disease-prediction models.
The plague of 2005 will ultimately provide a beginning point for virtual epidemiology. According to The Economist, Fefferman says Blizzard Entertainment will consider releasing more viruses into "World of Warcraft" for the purposes of scientific study. That may be bad news for some characters in "World of Warcraft," but potentially very good for humanity.
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