Joker Infection

Joker Infection
Batman under the effects of the Joker Infection.
Series	Batman: Arkham
First appearance	Batman: Arkham Knight (2015)
Symptoms	Overwrites the infected's personality and identity until they become a clone of the Joker

The Joker Infection (also referred to as Joker's Disease) was a unique condition that was created by the Joker's mutated blood that slowly turned the one infected into the Joker.

History

Prior to the events of Batman: Arkham City, Joker spent weeks sending samples of his blood to hospitals all over Gotham City in order to poison as many Gothamites as possible with the Titan Disease which ultimately led to his death.

Although Batman managed to find and distribute a cure to the infected and rounded up most of Joker's blood samples with the help of Commissioner Gordon, five people were given blood transfusions with blood samples they missed due to hospital errors. It was sometime afterwards, that those individuals began showing signs of the Joker Infection.

Batman linked the infection to Creutzfeldt–Jakob disease] (or CJD) but it was mutated beyond anything on medical record. Like CJD, the Joker Infection attacked the brain. Unlike CJD, that unique infection was not fatal, and instead it slowly made the host inherit the personality and other traits of the Joker until they become the Clown Prince of Crime completely.

It was shown that Scarecrow's new strain of Fear Toxin could strengthen the Joker Infection and it's effects to the point of causing hallucinations. In Batman's case, a hallucination of the Joker appeared that represented the embodiment of his worst fears. So far, there was no known cure for the Joker Infection other than almost indomitable will.

Victims/Infected

• Christina Bell
• Johnny Charisma
• Albert King
• Henry Adams (Suppressed most of the effects to fool Batman.)
• Batman (Used sheer iron will and possibly Fear Toxin to combat the infection and prevented himself from becoming the Joker.)

Trivia

• Although unlikely, it's speculated that the very first time that Batman showed symptoms of the Joker Infection was right after he defeated Mr. Freeze in Arkham City. He hallucinated the Joker's face in place of Freeze's while he attacked the latter.
• It was never fully revealed just what caused the creation of the Joker Infection other than it originating from Joker's mutated blood. However, it was probable that the chemicals that caused the Titan Disease (and maybe the chemicals already in the clown's blood) caused Joker's blood to mutate and caused the Joker Infection.
• Aside from the two names stated above, Joker referred the illness as Joker-itis and Mad Clown Disease.
• It's shown that, despite having cured himself in Arkham City, Batman was still infected with Joker's blood by the events of Arkham Knight — considering that Batman only took half a dose of the cure, and intended to give Joker the other half, it could be assumed it was not enough to completely cure him in the long run. It's also possible that the particular sample of Joker's blood that was injected into Batman couldn't be cured along with the Titan Disease because the Joker Infection was a result of a mutation and was not really a poison like the Titan Disease.
• The above theory probably isn't true. Batman was cured of the Titan disease, however the Joker disease is something else entirely; it's something that Joker has in his blood that contributes to his insanity, with or without Titan. This is why the other 4 jokers and Batman don't have symptoms of physical illness, the effects are purely behavioral and psychological.