Zombies are a type of antagonist depicted in a wide variety of contemporary popular culture, but brought to prominence by George A. Romero's film, Night of the Living Dead. Never actually called "zombies" in that film, Romero's reanimated, cannibalistic "shamblers" have nevertheless displaced the mindless voodoo slave as the definition of a "zombie" in the public imagination.
Zombies transcended the trope of Hollywood monster with Max Brooks' arguably humorously-intended book, The Zombie Survival Guide: Complete Protection From The Living Dead. Although a work of humor written by the son of comedian Mel Brooks, the Zombie Survival Guide nevertheless sparked a public interest in survival preparation.
The organization Zombie Squad uses the threat of a zombie outbreak as a metaphor for the other, more plausible disasters for which we might prepare. The infectious nature of zombies is particularly salient to the threat of epidemic disease, and the mass hysteria and panic that follow from a zombie uprising are common to those that accompany a natural disaster such as Hurricane Katrina. Yet zombies, in their literal form form, remain an enduring image, and preparing for a hypothetical zombie outbreak remains a useful intellectual exercise for survival preparation in general.
However, there is a danger to thinking of zombies only as a metaphor. The anthology The Apocalypse Reader, edited by Justin Taylor, includes a work by Jeff Goldberg called, "These Zombies Are Not A Metaphor," in which the protagonist endeavors, in vain, to persuade his companions to take the zombies that have overrun his town as a serious, immediate, and physical threat, rather than as an abstract metaphor for the other troubles of our age. Zombies, today, function primarily as a metaphorical construct for other, more plausible threats, but a few mutations of a viral genome may bring them out of the realm of fiction, and into the realm of the real. The remainder of this article will deal with zombies as a hypothetical but literal threat.
Also known as "Romero Zombies", they are the quintessential form of zombie, and are to zombies what Béla Lugosi is to vampires. Shamblers exhibit varying degrees of decomposition, seem to exhibit poor muscle coordination and move exceptionally slowly with a characteristic shambling gait, from which they are named.
Often they are perceived to possess much greater physical strength, perhaps in compensation for their limitations, making it virtually impossible to pry anything, especially yourself, from their cold dead hands.
Sometimes called "Ragers", these are not zombies in the strictest sense, but rather living humans with an altered mental state that leaves them incapable of high levels of thought and rationality. The terms "Rage Zombie" and "Ragers" are interchangeable. Rage Zombies exhibit the behavior and the mental capacity that can best be compared to that of a wild animal. A Rage Zombie does not possess the capacity of reason nor of language. However, unlike wild animals, Rage Zombies do not feel pain. The reason for this has not yet been fully explained.
The rage characteristic of these types of zombies is comparable to the extreme aggression exhibited by a wild animal that is seeking to project its control over a physical area and other animals. The most basic instinct of the Rage Zombie is to use physical force to destroy humans. Rage Zombies will not attack other Rage Zombies. The reason for this has not yet been fully explained.
It is widely believed that Rage Zombies possess in their blood a virus that causes their condition. The "rage virus" is transmitted to non-infected humans in the same manner as other "non-zombie" blood borne pathogens. Exposure in this manner to the blood of a Rage Zombie has a 100% probability of infecting a "normal human" and causing them to deteriorate into the condition of a Rage Zombie. (Note: there have been extremely isolated cases in which a human exposed to the rage virus has not deteriorated into a Rage Zombie. However, these infected persons were still able to transmit the rage virus to non-infected humans. The reason for this has not yet been fully explained.)
Because Rage Zombies are altered living humans, they can be destroyed in manners that would not have an effect on other types of zombies. For example, Rage Zombies need the "nutrition" that is gained from eating non-infected humans. Thus, Rage Zombies can starve and die.
Rage Zombies do not experience shock when traumatically wounded but will experience the effect to their physical structure. For example, if a Rage Zombie has its legs removed, it will eventually bleed out and cease to function, but it will be capable of functioning far longer than a non-infected human would with the same injury.
In nearly every circumstance, Rage Zombies exhibit similar behavior to Runners.
While most zombies move in a noticeably slow and strained manner, Runners have little to no deterioration of motor functions (while decay has not yet occurred). Runners are able to sprint as fast (and sometimes faster) than the average human, and can maintain that speed almost indefinitely. The retention of their motor functions allows Runners to operate with much of the same physical capabilities as do living humans.
However, they share the characteristic of Rage Zombies and Shamblers and also operate with an altered mental state that leaves them incapable of high levels of thought and rationality. They too exhibit the behavior and the mental capacity that can best be compared to that of a wild animal.
The Runners' degree of speed and mobility makes them especially dangerous as they often can not be outrun, as can Shamblers, and their stamina is virtually indefinite. Runners often present some degree of decay, or "undead biology", as seen in Shamblers. While the share many of the same physical characteristics in terms of appearance, Runners are more physically resilient than Rage Zombies because Runners are in fact deceased, reanimated human beings.
Because a Runner is dead, it can not bleed out nor starve, as can a Rage Zombie. Runners are capable of sustaining massive physical damage and continue to operate at some level. A Runner can be incapacitated by delivering destruction to its physical structure, but it will continue to operate at some level and thus, still be dangerous.
The only manner in which a Runner can be immediately and permanently stopped is to completely destroy the brain. Note: if the head of a Runner or Shambler is separated cleanly from its body, this zombie will still for some time be dangerous and capable of infecting living humans through its bite.
As with Shamblers, the Runners experience biological decay.
Decay (or decomposition) is the physical state that is the result of the cascading effects of the ending of biological activity from the cellular level to the organ level to the organ-system level.
Living organisms constantly experience cellular-level regeneration and repair. For example, living humans constantly shed dead skin cells and replace them with regenerated skin cells; living human muscles are constantly repairing microscopic tears throughout their use. Shamblers and Runners are technically dead and thus do not regenerate nor repair any parts of their physical bodies.
The accumulated effect of this lack of regeneration and repair is biological decay.
In general terms, a virus is an infectious agent that is composed of genetic material contained within a "shell" called a capsid which is composed of protein material.
A virus essentially exists in two states - inert and parasitic. On its own, a virus does not have the ability to reproduce, metabolize nor adapt. A virus that is inert, can be basically considered a "landmine"; it lies in wait, requiring another organism's contact in order to "explode". The parasitic nature of a virus comes into play when an organism encounters the virus and, if able, the virus begins the manipulate the host organisms normal functioning.
The Solanum virus is widely accepted as the cause of Zombieism in both Runners and Shamblers. Although many facts are known about the Solanum virus and the Rage virus, their exact nature is still the subject of great medical and scientific debate.
A fact commonly accepted by the majority of worldwide medical and scientific authorities is that both the Solanum and Rage viruses cause infection in humans via contact with the human bloodstream. Because of this fact, most medical and scientific authorities consider both viruses to be blood borne pathogens.
Supernatural curses used to create a "zombie" are most commonly attributed to the belief system used by the religious tradition of "voodoo". Voodoo is arguably classified as a religion because it incorporates into its belief system the concept of gods or supernatural entities.
However, it is widely accepted that a supernatural curse does not directly affect the physical body of the human victim, but rather the spiritual aspects of the human condition (i.e. the soul, life-force, etc.). The medical and scientific communities, as well as professional zombie hunters, do not classify "persons with supernatural curses" as true zombies.
Toxic waste is by its very definition "toxic" and as such is not conducive to the environment needed by a virus to survive.
Human beings affected by toxic waste may either die or experience the physical condition in which various stages of their biological functions terminate, thus reducing their mental and physical capacities to a "zombie-like state". They are not affected by an organism that biologically replicates when introduced to a host (as a virus would).
Current medical and scientific information relating to the Solanum and Rage viruses demonstrate that they require similar environmental conditions as other known viruses.
While some characteristics of known-virus behavior apply to the Solanum and Rage viruses, there is heated debate among the scientific, medical and professional zombie hunting communities as to the various procedures that can be utilized to destroy or protect against each of these viruses.
Voodoo powder is believed to be a toxin in powder form that is created by practitioners of Voodoo (aka Vodoun) from a variety of ingredients, the exact natures of which are not well known at this time. One story is that Voodoo witch doctors use tetrodotoxin from the Puffer Fish to cause the victim enter a death like coma. The victim is buried with great ceremony and is dug up later from the grave not as a walking corpse but as one of the "living dead" who serves the witch doctor who created it.
Voodoo powder is a toxin that does not biologically replicate when introduced to a host (like a virus) but rather only terminates in various stages the biological functions of the human host, thus reducing their mental and physical capacities to a "zombie-like state". Thus it is believed the shambling gait and loss of higher cognative functions is a byproduct of the toxins combined with the madness of being buried alive.
Human beings who are under the effect of the voodoo powder toxin are not considered by medical and scientific communities, as well as professional zombie hunters, to be true zombies.