User:Kanesteven/Zombie Plague

Summary
The Zombie Plague was an in-game event in the World of Warcraft (WoW) virtual world that allowed players to become infected by a virus that, if left untreated, ultimately transformed them into zombies. The event ran from October 22 to November 12 2008 and heralded the release of the second major expansion for WoW, Wrath of the Lich King. Players that were turned into zombies had access to special abilities and were automatically allied with all other zombies. The infection was spread by zombie players and NPCs alike and initially had a 10 minute incubation period. As the event wore on, more and more NPCs contracted the virus and the virus' incubation period was reduced causing a dramatic increase in the number of infected players. The event was tied to the lore of the game as the forthcoming expansion's storyline was centered around a demon and his undead minions.

The Zombie Plague event was recognized by some epidemiologists as a promising example of modeling real-world infectious disease propagation in a virtual environment. The concept was not without precedent. On September 13, 2005 the game's creator, Blizzard Entertainment accidentally introduced an extremely aggressive disease into the player population called the Corrupted Blood Incident. That event was noticed by academics as the first large scale model of disease propagation within a virtual environment. The Zombie Plague offered a more accurate model of disease propagation, but it was not without shortcomings. The Zombie Plague was also criticized by some experts as a poor model for real-world outbreaks since players were not explicitly averse to contracting the disease. Without the threat of permanent death or loss, it is difficult to capture true human behavior in a virtual world. Nonetheless, virtual environments are promising testing grounds for studying epidemics without causing physical harm to populations in the real-world.

Event Lore
The Zombie plague was instigated by Blizzard Entertainment as a means of foreshadowing the dark turn the storyline of World of Warcraft would take with the release of Wrath of the Lich King. A character named Arthas was corrupted by evil and ultimately became merged with the soul of a long-dead warlock (Ner'Zhul) becoming the Lich King. The Lich King controls the forces of death and darkness and Blizzard sought to accentuate his rising power by infecting the game population with a disease that, if left un-treated, would turn players and non-player characters into zombies. The event lasted three weeks and grew in intensity to simulate the rising struggle of the living races against the Lich King's necromancy.

During the height of the plague the whole world was nearly overrun by zombie players and NPCs alike. In Warcraft lore, the Lich King attempted to use the plague to overcome the living races. Eventually, the living races fought back successfully and managed to stave off the plague for the time being. The disease was purged from the game environment the day before the new expansion was released. Various regions of the game world continued to feel the effects of the zombie plague, though the infection was limited to NPCs and could not be contracted by players any longer.

Implementation in Game World
The Zombie plague was first introduced to the game world via some crates in a southern coastal region called "Booty Bay". The crates were labeled "conspicuous crate" and opening them gave players a 10minute disease called "You're Infected!!". NPCs called Argent Healers were positioned all around the game world and they would instantly cleanse the disease from infected players and NPCs that came near them. Players could infect NPCs and any NPCs that died while infected with the plague also were reanimated as zombies. The outbreak was mostly contained by the large number of Argent Healers positioned in the major towns around the game world. As the plague intensified, the number of Argent Healers was reduced. Furthermore, Argent Healers could be killed by zombies further reducing their numbers. Gradually, new crates began to appear in various high traffic areas of the game including Elwynn Forest, Durotar, and Ghostlands. Additionally, the plague's incubation period was reduced from 10 min to 5 min to 2 min to 30 seconds. Eventually, large numbers of players began to form "raids" and attacked towns. The plague could be spread easily to NPCs and players alike and the absece of Argent Healers made it difficult to contain.

Zombie Abilities
Any player turned into a zombie had access to new zombie abilities, however, normal player abilities were not available once transformed. Listed below are the names of zombie abilities and a basic description of the mechanics of each.


 * Mangle          Increases damage dealt by zombie by reducing victim's armor
 * Retch           Spit green slime cloud that:
 * Heals zombies that stand in the cloud
 * Reduces the movement speed of non-zombie players standing in the cloud


 * Beckoning Groan Call 4 zombie NPCs to mimic your actions for a short period of time
 * Lunge           Doubles normal zombie movement speed for 10 seconds
 * Zombie Explosion Causes zombie to explode and infect anyone that is near them

Player Reactions
Though the event was seen as a success by many players, most players and blizzard included felt that the event was a failure, due to the nature of the event being blocking off many normal aspects of the game.

"The response from the zombie invasion was overwhelmingly negative, and so we took that feedback and made sure that future events would be fun and interactive, but not a griefers paradise. Obviously there are plenty of griefers though, and they'll always remember it and always compare events to it. Nothing will ever be as 'fun' as the zombie event was, and that's sort of the point, it's not a type of fun that most people enjoyed. "

Blizzard Entertainment at the moment has no plans to create another event similar to the zombie plague invasion.

Research Method Applications
The zombie plague, like the preceding corrupted blood incident, excited some epidemiologists because it showcased a possible use of virtual worlds to analyze real-world disease propagation. The zombie plague was notably different from the corrupted blood incident and offered some superior characteristics for the study of infectious diseases. However, the event was not without its critics. Some of the prominent proponents of the corrupted blood incident were skeptical that the zombie plague was an accurate depiction of disease propagation, or that virtual worlds could ever offer a realistic means to study the spread of infectious diseases.

The zombie plague was praised by some researchers for offering a more realistic R value. The R value in epidemiology refers to the number of people that a single infected individual is likely to infect. Typically, diseases like small-pox and the flu have low R values, typically between 1 and 15. The R value of the corrupted blood incident was estimated to be more like 25-30, which was unacceptably high and did not properly reflect the nature of diseases in the real world. Many researchers were also encouraged by the fact that it was possible to cure the zombie plague disease. The corrupted blood disease could not be cured at all and exposure to the disease guaranteed transmission. In the real world, there is usually some mechanism for treating a disease and carriers will tend to seek out those cures.

Some researchers, including Nina Feffermen, Eric Lofgren, and Neil Ferguson were skeptical that the zombie plague was, in fact, an improved model over the corrupted blood incident. Eric Lofgren wrote that he was not convinced that the transmission mechanic was actually any more accurate than that of the corrupted blood plague. He pointed out in his blog entry that the zombie players could guarantee infection by successfully and actively engaging in the correct behaviors. Players were only able to avoid infection by either killing zombies or avoiding them altogether. Thus, he stated that the actual R value for transmission was still unrealistically high. Additionally, he observed that numerous elements of the plague event were "fun and engaging" and thus poorly modeled the actual state of infectious diseases. Players were essentially encouraged to participate in the plague experience and there was no serious ramification for becoming a zombie. Thus, instead of instinctively avoiding the disease, many players attempted to contract it willfully, and aggressively spread it to other players.

Furthermore, all three researchers felt that the zombie plague was too carefully controlled to genuinely simulate a pandemic spread. Information about the precise nature of the event was distributed by Blizzard Entertainment and fan sites were quick to publish detailed information on becoming infected and treatment options. Thus, the disease was far too predictable and the event did not capture the spontaneity and lack of information that typically accompanies disease outbreaks. A large amount of what causes the spread of infections comes from the average person not knowing much about the disease. Thus, the publicity associated with the zombie plague effectively helped to curtail the spread of disease that would normally accompany public ignorance.

Altogether, the zombie plague gave researchers an additional scenario that could be analyzed for parallels to real-world epidemiology. In the end, the event offered some improvements over the corrupted blood incident, while still being flawed as a model for serious disease study. The major obstacle to be overcome with any virtual environment is to have serious enough ramifications for infection that participants are as averse to contracting the disease as individuals are in real life. The zombie plague represents another more step towards building such an environment.