Pestilence in a World of Warcraft

In an effort to bump up gameplay in the online realm of its "World of Warcraft" (WoW) massively multiplayer online role-playing game (MMORP), Blizzard Entertainment two years ago introduced a new villain, known by the colorful moniker of "Hakkar the Soulflayer."

Little did the company know that the virtual plague Hakkar would spread to avatars in the online world would help epidemiologists learn a thing or two about human behavior during a pandemic.

That's exactly what happened when Hakkar began infecting players with Corrupted Blood, a virus causing an outbreak to spread through the virtual world of some 4 million players in September of 2005, according to researchers from Rutgers University and Tufts University. In fact, Nina Fefferman, assistant research professor of Public Health and Family Medicine at Tufts and codirector of InforMID, and Eric Lofgren of Rutgers, her former student, had joked about just such an event in online gaming a few weeks before the plague actually happened.

"[Players' behavior in the game] is analogous but not directly equivalent," Fefferman told TechNewsWorld. "The analogy just sort of made itself plain to us once we were thinking about it to begin with. And so certainly, looking at how the anecdotal reports of the disease being spread were coming in just instantly looked to us like a really normal [outbreak] hitting an urban center. And once that connection was made, everything else just fell into place."

In the report, published in the journal The Lancet Infectious Diseases released Monday, Fefferman and Lofgren use the WoW outbreak to gain insight into people's responses during an epidemic. Ran Balicer, an Israeli researcher at the Ben-Gurion University of the Negev, published a similar paper in the journal Epidemiology in March.

Patient Zero

The Corrupted Blood virtual plague began when Blizzard programmed into the virtual world a new land, Zul'Gurub, a dangerous realm for high-level WoW players. In it lived Hakkar, a winged serpent who could cast a debuff, or spell, the negative effects of which would unfurl over a set amount of time, infecting characters with the Corrupted Blood illness.

Corrupted Blood, however, was contagious. It damaged not only those directly infected by Hakkar but any character within close proximity of the afflicted players as well.

Once a character was infected, the spell would drain 250 to 300 health points from the contaminated player every few seconds. Players whose avatars were stronger could counteract the plague's affects due to their higher stamina. They could also use healing spells and resort to other high-level powers to survive until the disease eventually ran its course. Lower-level avatars, however, were killed within a few seconds.

Blizzard engineers perhaps did not account for the vagaries of human behavior. The game developer had built a virtual quarantine area meant to contain the virus, but some gamers -- being gamers -- began working around it, healing themselves just long enough to leave the quarantined zone. Some then used the virus as a weapon to infect the online world's cities, according to Rob Enderle, principal analyst at Enderle group and a WoW player.

"People who were infected would escape quarantine and spread the disease," he told TechNewsWorld. "Some folks figured out how to use it as a weapon, evidently by infecting pets and dismissing them before the infection ran its course, then summoning them back in populated areas with a near nuclear bomb effect on lower-level players.

"Eventually, players learned to avoid cities -- which became uninhabitable -- and large groups," he continued. "The only sure way I know of to avoid infection was not to log in, but so many of the players are nearly addicted to the game that wasn't really an option, and it seemed to make the game a bit more interesting."

When Blizzard realized that quarantine zones had failed, the game maker eventually ended the outbreak by resetting the game a few days later and removing the properties that allowed the Corrupted Blood spell to spread from one character to another.

Real-World Behavior in a Virtual Environment

While the WoW pandemic was the "result of unintended interactions between different elements of the game," Fefferman and Lofgren wrote, "it nevertheless shows the potential of such scenarios for the study of infectious diseases.

Games, the researchers went on to explain, are similar to the virtual populations epidemiologists create in computer models to study human behavior during epidemics. However, MMORPGs have the added benefit of human users who could "further illustrate human behaviors in actual outbreaks scenarios.

"Since the influence of individual behavioral choice has been shown to greatly affect the range of societal outcomes in many fields including epidemiology, differences between the human-agent simulation and a pure computer simulation of the same disease, incorporating the vast complexity of human behavior -- rational or otherwise -- could examine the effects of these behaviors on the course of an outbreak," they asserted.

Fefferman plans to contact Blizzard and makers of other online games to introduce other similar scenarios into their MMORPGs to facilitate further research in this area, she said.

Interesting, But ...

"The finding I found most interesting was that many people would try to either ignore, avoid or somehow get around orders of quarantine. I find that very telling because my gut sense says that is correct," Dr. Bill Scaffner, chair of the department of preventive medicine, Vanderbilt University Medical School, told TechNewsWorld. He had never imagined an online game would be grist for an epidemiologist and might actually be useful in helping researchers think about pandemic planning.

"Although our Canadian cousins were very compliant, as I understand it, during the quarantine orders when they were infected with SARS, I think the United States population should not be confused with our more orderly and sober northern cousins. We are a much more turbulent group," he said, referring to the outbreak of severe acute respiratory syndrome in November 2002 and July 2003 that spread from China to other Asian countries, then to the Middle East and eventually Europe and Canada.

That said, however, Schaffner cautioned that using online games as a model of human behavior during epidemics returns only limited data. As gamers are a self-selecting demographic -- the majority of whom are young men with the means to afford computers and Internet service -- their behavior is not necessarily indicative of an entire population.

"This was a bit of a lark. All models and tabletop exercises and games of bioterrorism and pandemic planning are useful up to a point," he opined. "But it is not the general population that uses these games. It's a subset of the population that tends to be young and tends to be male. And in so far as you don't over-interpret the results, I think that's fine. It may indeed provide some additional information as we all go forward and try to protect ourselves as a complete society.

"It is difficult to use this the way you would a carefully stratified sample of the national population, a Gallup Poll, for example. It's nonetheless intriguing. It's kicky. Who would have thought? It's kind of fun. I'm just saying let's not over-interpret the data. On the other hand, sure, let's have a look-see what happens and it may give us a moment's pause and moment's thought to consider some things we hadn't considered as seriously as we might have."