A viral zombie is a zombie that came to exist through the spreading of a particular zombie virus. Zombie Infection is the only real dangerous type of zombie outbreak, due to the ability of the affliction to spread to others. This is the primary group that zombie survivalist movements, such as the web based organzation "ozort", focus on dealing with.
It's a common myth that a viral zombie can only be effectively stopped via severe head trauma.
A viral zombie is a specific type of zombie (out of a number of different kinds of zombies), that is infected through a virus, and is capable of spreading the virus to others it comes in contact with. The viral zombie is the most common kind portrayed in movies and video games (such as Dawn of the Dead and Resident Evil). There's a number of types of zombie virus possibilities, ranging from Lyssavirus X to Filonecrosis, as well as a few fictional zombie viruses such as Solanum.
A viral zombie is a destructive force onto itself, where the host willingly spreads its infection to others.