In late September of 2005, the world was struck with a terrible, virulent plague. In the early days of this plague, it was believed to be well under control. Casualties were few and far between, constrained to indoor quarantine zones, protecting the outside world from the violent malady. These quarantine zones did not last long. Common vermin and pets acted as carriers, delivering this plague out to the greater world.
Men, women and children were all infected. The young died instantly. The old were forced to weather a tortured, wasting existence prior to their death. Innocent bystanders acted as unknowing carriers, delivering the plague from one victim to the next. The death toll rose high enough that major city centers had been almost completely killed off, leaving only piles of corpses to rot in the streets.
We're not talking about the Black Death or a modern pandemic like SARS or H1N1. We're talking about Corrupted Blood, a disastrous plague that struck within the virtual world of Azeroth, hurtling World of Warcraft into the public eye and placing it under scientific scrutiny.
Corrupted Blood was a debuff mechanic from the first iteration of Zul'Gurub from patch 1.7, utilized in the Hakkar the Soulflayer encounter. Hakkar would periodically stun the entire raid and drain their blood, healing him. To prevent this, players would need to expose themselves to Corrupted Blood, which spread to nearby raid members. When Hakkar drained your blood, he would be damaging himself because of your corruption.
Normally, Corrupted Blood would fade from your character on its own. It wasn't a very long debuff, and it faded from you when you died. One or the other would almost certainly happen before you managed to get back to your home city to spread it to innocents. However, back in classic WoW, hunter pets kept their debuffs when dismissed. Hunters would poison their pets with Corrupted Blood, dismiss their pet, hearth back to Orgrimmar, Ironforge or some other major population center, and call their pet back. Their pet would spread Corrupted Blood and begin the pandemic. It would spread from character to character until the entire city (and beyond) was infected.
Hunter pets played the exact role that vermin do in real-world outbreaks. Hunter pets were the rats and fleas of the bubonic plague, the mosquitos of malaria, or the ticks of Lyme disease.
We don't know which player was Corrupted Blood's patient zero, but we do know that the first major outbreak of the plague occurred on the Archimonde server.
The blood plague quickly became a model for what a true pandemic in our modern world could look like. Azeroth is a robust, highly populated virtual world full of human-controlled characters. The spread of the plague was unquestionably the work of human beings, most of them fully aware of what they were doing when they began spreading the plague. The model they created was a strong representation of humanity's reaction to a pandemic, how it might spread, and how a person might spread it.
Most players involved were innocents -- people standing around in a population center, totally unaware of what was coming their way. They became infected, went through the stages of infection, and died roughly where they began. Others, upon being infected, knew what was happening: They were going to die. Death at the hands of a pandemic offers you a choice: Accept it, lie down, and die peacefully ... or become a carrier and take some poor son of a bitch with you.
NPCs could also be infected; they did not react to the plague but could spread it. The NPCs each acted like Typhoid Marys, asymptomatic carriers who were perfectly healthy but for their ability to infect others nearby.
The uninfected were driven away from population centers, out into the forests, jungles or relatively empty countryside, trying to avoid other players at all costs. Players couldn't go to the auction house. Players couldn't go to the bank. They avoided their usual hubs and farming locations. The blood plague caused a complete collapse of Azerothian society, and the implications for Earth were terrifying.
Would our modern world's methods of quarantine be enough to prevent a pandemic on that scale? If not, did we have the resources to control it in other ways? Would the dark shadows of the human psyche we saw crawl to the surface during Azeroth's blood plague do the same in the real world? Would the dying become willing carriers simply because they were going to die anyway? Was our economy that vulnerable? Would our civilization similarly collapse? If the human population fled cities to escape the pathogen, where would they go? How would the population migrate? If they fled out into the wild, could we still reach them with medical supplies? What sort of people would be most likely to become willing carriers of the pathogen? If there were a shortage in medical supplies, what type of people should have priority to minimize the spread of illness?
Perhaps even more chilling than these questions is the fact that this virtual plague was used by government officials to model what could happen if terrorists used a biological weapon to sow chaos. If terrorists or extremists used this method of attack, how would they do it? What approach would they take? What sorts of locations would be targeted? How would the populace react?
The players who caused the blood plague were just getting their jollies off. The players who were caught in the crossfire either laughed it off or got angry and logged off, because a few days later, everything would be back to normal. But to the outside world? To government agencies, scientific researchers, and everyone in between? You couldn't ask for a better epidemic simulation.
I do recommend watching the below embedded video on the topic, but make sure you're somewhere comfortable before you do so. It's nearly an hour long.
Blizzard didn't forget the "success" of the blood plague. It was quickly eliminated and patched out of the game, but it still stood as a spectre of what could happen when things go wrong on Azeroth. Prior to the release of Wrath of the Lich King, the blood plague reared its ugly head again in the form of the Scourge plague: the Zombie Invasion of '08.
The zombie invasion did not follow the same natural, player-created progression that the blood plague did. It was an intended game mechanic rather than a catastrophe created by players in an open environment. In that way, it was not as useful to outside observers as an epidemic simulation, but Blizzard perfected other aspects of the simulation. Infection was not instantaneous, there were varying levels of exposure, and the risk of exposure increased according to the number of infected. One person couldn't infect an entire crowd of people at one time, but one person could infect a handful of people, and that handful infected a handful each, and so on. It created a scenario in which there was a believable source of infection -- civilization's food supply, rather than a blood god from beyond the mortal realm.
Humanity probably doesn't need to worry about blood gods in the real world any time soon.
At the end of the zombie invasion, Blizzard came to the conclusion that players probably don't really enjoy being infected by a civilization-collapsing pandemic. There were a few core flaws in this second plague that caused such a violent player reaction to the event, but that's a discussion for another time. Say ... when Archivist gets to Wrath of the Lich King.
The WoW Archivist examines the WoW of old. Follow along while we discuss the lost legendary, the opening of Ahn'Qiraj, and hidden locations such as the crypts of Karazhan.