Bliss Virus (Doctor Who Series Three)

First Appearance: Doctor Who Series Three Episode Four: "Gridlock" (Mentioned Only)

Mutating from a compound within the chemical mood drug known as Bliss, the Bliss Virus became airborne and killed the whole of the world in "seven minutes flat." Due to the prevention of the Senate, Novice Hame and the Face of Boe (despite the Senate's death) the virus was unable to infect anyone else after the initial epidemic and it itself "perished."


"Gridlock":

During her explanation of what happened twenty four years earlier with the death of New NewYork at the Senate building, Novice Hame shows the Doctor a used Bliss Patch that she had removed from the corpse of a user and tells him about the how the virus had killed New Earth in a matter of minutes. 

Just before the Senate had succumb to the virus; they sealed off the under-city from the over, leaving the system to be run automatically with the limited power that was left (and eventually had run out) and activating an 100 year quarantine that stopped any neighboring planets from helping them. In the outbreak The Face of Boe used his mist to protect Novice Hame from the virus; leaving them the only two individuals in the over-city. 

Yet the virus was unable to sustain itself without anymore hosts to infect and it eventually died leaving the planet able to be repopulated once the Doctor opened the roof of the Motor Way and let the residents of the under-city return above ground to the over-head.