People who have played Resident Evil know what I'm talking about.
The virus is called Solanum. The virus infects the frontal lobe of the brain by flowing through the blood stream. After infecting the victim's frontal lobe it uses the cells there to replicate while destroying the frontal lobe. All functions heart functions cease and the vivtim is pronunced dead. The virus changes the brain into an organ that is not relaient on oxygen. The circulatory system is shut down, along with the digestive system. The body is then reanimated 23 hours later as a zombie.(Brooks,Zombie Survival Guide pg 4)
A scary thought huh?