For more information, please see Necroa Virus on Plague Inc. Wiki.
The Necroa virus was released on Tueday, February 26th, 2013 for iOS and Tuesday, March 12th same year for Google Play in the 1.5 patch. Its main feature is that it turns people into zombies when you kill them. It introduces many features such as abilities and more symptoms.
Unclassified. Early analysis suggests extreme regenerative abilities.
The Neurax Worm plague must be completed on brutal or it can be purchased for 1.99.
The Necroa Virus is, at first, similar to a regular disease, and can be cured as normal. However, its initial symptoms will quickly reveal the plague to the world after a number of people are infected and are much different from the other initially unlockable symptoms for other diseases. There are two branched symptom chains that will affect the infected person differently. Both chains culminate with the Cryptopathic Reanimation Symptom trait. Upon acquisition of this trait, the game will take a different turn. People that are and have died from the disease's other symptoms (Cannibalism, Pschosis, or both) will reanimate as zombies and will go eat and kill people turning them into zombies.
At this point, the cure will become useless, and as your plague and zombies ravage the world for some time a random country in the world (usually a rich one and one not as affected by the zombies as other countries) will become a Z-Com Headquarters. The Z-Com in that country will attempt to exterminate the zombies within its borders and once it has secured itself it will slowly spread to other countries if left untouched, stopping Zombies in their tracks unless dealt with swiftly and brutally. If not stopped fast enough your zombie armies will begin to succumb to decay even if you have all of the abilities that prevent this, opening the way for the Z-Com to spread to other countries. Ultimately the Z-Com will triumph if they have establish themselves in too many countries and you will eventually will suffer defeat as the last zombies decay or are exterminated.