To use any special plagues, all of the first seven plagues must be beaten on Brutal difficulty. They can also be purchased for $1.99. Only the first two special plagues are currently available.

Neurax Worm
"Manipulative organism that burrows into the brain."
This plague has the ability to control its host. It begins with three new transmission options: Concertina Locomotion, Eggs, and Genetic Swap. Concertina Locomotion and Eggs are required to unlock the typical transmission options. Genetic Swap unlocks Mutative Regeneration, which increases random mutations, and Corpse Feeder, which increases infectivity if there are corpses.
Necroa Virus
"Unclassified. Early analysis suggests extreme regenerative abilities."
The Necroa Virus is the game's zombie plague. It is cured very quickly, so the player needs to unlock its special ability, Cytopathic Reanimation, as soon as possible. This will bring the dead back to life, thereby continuing to spread the virus even after a cure is found. Z-Com, a military facility, will begin to establish itself in healthy countries, and will greatly slow the spread of the plague.