The Zombie

The modern notion of the shambling undead has existed for decades... but is it biologically feasible?

Note: much of the science you read in this particular volume was adapted from the FVZA website. You can visit them here.
For years I have been the sole pioneer in the study of diseases that most scientists would not deign to research. At best, they see my work as unpleasant; at worst, an affront to the scientific method.
But I believe that my time of vindication is imminent, and my research into these little-understood viruses will soon prove invaluable to all of humanity.
In a previous volume, I presented the Human Vampiric Virus, a disease which turns its victims into bloodthirsty revenants bent on destruction.
But while the threat of HVV remains to this day, it isn't the only insidious pathogen I've discovered.
Following is a summarized account of my work with an equally terrifying disease, which I have dubbed the Human Zombism Virus, or HZV. Should this virus go unremedied, its flesh-hungry sufferers could pose a threat to humanity that may even surpass HVV. Now, permit me a moment to provide some context for my research. I humbly ask you to let your mind remain open to what follows; the future of our society may well depend on it

---

In my youth, an unrelated research project took me to the island of Hispaniola, and specifically to several rural regions throughout Haiti. It was there that I first learned of the legends of dead bodies that had been reanimated by voodoo magic. Corpses pulled from their eternal slumber through an act of necromancy performed by a sorcerer called a bokor. Despite the prevalence of the accounts of so-called zombies, I was skeptical.
Still, as legends are often based on some truth, my curiosity was piqued. Unfortunately, my time in that beautiful country was cut short, as my unrelated research grant was abruptly terminated. I returned to America and observed with fascination as the zombie began to make appearances in Western media.
Books such as Seabrook's "The Magic Island" and movies like "Night of the Living Dead" depicted them as shambling corpses single-mindedly intent on consuming brain matter. Then, only recently, my research into the Human Vampiric Virus would once again bring me into contact with the zombie, not by magic as the legends told, but through an insidious infection that robs its victims of their humanity, transforming them into mindless, decaying shadows of their former selves.

The Virus

I hypothesized that the zombie plague is in fact caused by a virus from the order Mononegavirales, negative-strand RNA viruses that cause Ebola, measles, rabies, and of course, vampirism. I have determined that HZV, or the Human Zombism Virus, is a zoonotic virus, initially spread to humans by a lowly tick from the family Ixodidae. These ticks are found in great numbers in numerous tropical regions, including Haiti, where I suspect the virus may have originated.
Tick-borne pathogens are certainly nothing new, but rarely are the diseases they spread so devastating to humans as HZV. Once bitten, the unfortunate victim will begin to undergo a kind of transformation—but the source of the infection isn't limited to ticks. For one, a tick may bite a rat, raccoon, or other animal, which in turn may pass the virus to humans, though a direct bite is certainly possible and in rural areas, even likely.
But the virus survives quite well apart from a host. I have personally tested freestanding water in which the virus survived for nearly three months. This ability makes HZV a major threat to water supplies, and though certain treatments can remedy this, this danger should not be ignored. Of course, one of the most common vectors of transmission is via the bite of an individual infected with HZV, where it travels into a fresh victim's bloodstream through the infected saliva.
Once inside the body, the virus appears to enter the host's cells, replicating at an alarming rate. There, it utilizes a reverse transcriptase enzyme to produce DNA from its own RNA genome, and this new DNA is then absorbed into the host's nucleus and incorporated into its genome via an integrase enzyme. This effectively makes it a provirus, which in turn transforms the cell and directs it to synthesize new virions.
This is much different from other mononegaviruses, which do not produce DNA or use the nucleus for replication. It is, in fact, remarkably similar to the vampiric virus, though much smaller in size, and it's possible that the two share a common ancestor.
From the point of infection, visible symptoms occur quite rapidly, within one to two hours. Like HVV, victims will experience a headache, fever, chills, and other flu-like symptoms, along with extreme thirst, itching, and an increase in heart rate and overall metabolism.
This combination of factors, especially the latter two, facilitate the rapid proliferation of the virus and the onset of increasingly destructive symptoms. If bitten by an infected human, the infection is made worse by a bite wound filled with bacteria from the infected's mouth, causing even greater pain and inflammation.

The Transformation

I have broken down the stages of zombie transformation into three parts, which I have observed personally. The aforementioned symptoms could be considered stage one, with the victim progressing rapidly to stage two: coma. Though only lasting four to six hours, the accompanying fever raises body temperatures to unbearable heights, causing brain damage in virtually all cases.
Rather than being a peaceful sleep, the zombie coma is clearly uncomfortable for its sufferers. I must admit that despite their scientific necessity, these comas rarely fail to elicit feelings of empathy toward the subjects of my own experimentation. At roughly the midpoint of the coma, the victim experiences cardiac arrest, and blood flow, breathing, metabolism, and body temperature abruptly plummet to nearly nothing. It is at this point that the victim enters stage three: the transformation.
Anyone near a victim as they undergo the latter half of their coma could easily be forgiven for thinking that the victim has died. Nearly all metabolic function is sharply reduced for a period of up to roughly two hours.
It should be noted that the heart does indeed cease to beat, and it never resumes. I will explain this in more detail shortly.
It is at this stage that many an unfortunate victim has been left for dead or, tragically, buried alive. But no matter what is done with the victim when they are assumed dead, this brief reduction in metabolic processes likely accounts for the idea that zombies return from the dead or are reanimated corpses.
It may sound harsh, but abandonment or burial may actually be the best course of action, at least for anyone near the victim.
Gradually, the victim will awaken from their coma, albeit in a catatonic state. Within an hour, they will rise, shambling about, often seeking the flesh of anyone nearby, and in my testing, remaining unresponsive to virtually all stimuli.
Unlike common portrayals in the media, newly-awakened zombies are not mindless.
On the contrary, they clearly retain some memories and, if awakened elsewhere, they may even attempt to shuffle to their home, though this behavior is motivated exclusively by hunger and facilitated by simple, rudimentary habit. Indeed, loved ones may greet the victim only to find themselves attacked by the shell that remains.

---

Once more, I must thank you for reading up to this point. By now, it must have crossed your mind that surely all of this is the ravings of a madman, someone who has mistaken myth for reality. But I assure you, I have, through direct study, observation, and sample collection, obtained numerous pieces of evidence, each of which sheds light on the biological processes that occur as a result of HZV. I will attempt to describe these now, beginning with the zombie brain.

Anatomy and Physiology

As previously mentioned, recent victims of HZV do not wake from their comas as mindless ghouls. Some semblance of humanity remains, though only for a brief time. Due to a now barely functioning circulatory system, a point to which we'll return, failing organs, as well as brain damage sustained from the coma's high fever, victims' ability to think and reason disappears immediately.
Though certain habits and abilities, such as driving a car or even using tools, may remain for two or three days, the ability to perform even simple tasks disappears as their bodies, including their grey matter, begin to decompose. They are transformed into a hunting machine, and with a single-minded purpose: locate prey, capture prey, and feed.
Certain hormonal functions persist, though serotonin production diminishes almost immediately following transformation, and the scent of flesh appears to flush their brains with adrenaline-like neurotransmitters, causing their characteristic voracity.
Just as I did in the early phases of my research, you're likely wondering how a technically living creature could begin to decompose and even go on living without a functioning heart. In fact, these two symptoms are directly related. You see, once the heart arrests, both the nervous and circulatory systems are drastically restructured. And specifically, two fascinating phenomena occur in tandem.
First, by a mechanism as yet unknown to me, the nervous system appears to proliferate, strengthening pathways and innervating muscles to a level not seen in the uninfected human.
Second, and likely directly related, skeletal muscle assumes the role relinquished by the arrested heart, rhythmically contracting and relaxing. The increased nerve activity certainly assists with this, though it appears that the contractions that force blood through vessels in an almost peristaltic movement aren't terribly predictable, leading me to believe that zombie circulation is more of a reflexive action. Though it serves its purpose adequately, circulation via skeletal muscle is not efficient.
As a result, blood moves relatively slowly throughout the body. The blood itself becomes viscous and dark, like oil. This is caused by increased iron and bile levels, which also improves oxygen storage. On one hand, slowed circulation is an advantage, as it makes clotting more effective. On the other, tissues and organs struggle greatly as a result, and eventually, nearly all are completely overtaken by necrosis.
But thanks to their improved nervous system, zombies are able to remain mobile for much longer than their decaying bodies would otherwise allow. In fact, zombies have exhibited the ability to withstand significant trauma to both their central and peripheral nervous systems, and both exhibit impressive regenerative abilities. In some cases I have tested, even a severed spinal cord is a mere inconvenience.
I have documented zombies regaining the ability to walk after only 24 hours. Though the exact mechanism of this process of repair eludes me still, it appears that massive stem cell production and the absence of obstructive glial scarring are key elements.
But with zombie biology, there is always a give and take. For example, an apparent increase in olfactory receptors and limbic neurons bestows upon them the ability to smell humans from as far as a mile away.

But their other senses degrade greatly and rapidly. Due to the decaying of the lens and cornea, zombie eyes suffer severe myopia even early on, and as time passes, the scleras become red with inflammation, while the pupils become a gauzy white due to cataract formation. Necrosis will eventually take their vision, and even their eyeballs, completely.
It also takes their hearing and a majority of their sense of touch. But this decay also stunts their ability to feel severe pain, though chronic aching likely affects them greatly.
Between their poor coordination and increasingly necrotic tissues, zombies are not able to move much faster than a shuffle. This makes them relatively easy to avoid and is likely why we haven't seen a major outbreak of HZV in modern times. At least, not yet. However, perhaps counterintuitively, if you were so unfortunate as to be caught by a zombie, you'd quickly discover that they are quite powerful.
This is largely because, beginning in the coma stage, the muscles of the hands, forearms, and jaw recruit additional fibers. When contracted, these become a nearly unbreakable force. In fact, the average zombie's grip can exert up to 400 pounds of pressure per square inch, which is 10 times greater than a human's.
Perhaps even more fascinating, however, is what occurs in the jaw. During their coma, an increase in growth hormone facilitates the relatively rapid deposit of extra bone at the insertion points of major chewing muscles, such as the masseter.
Additionally, the masseter itself, as well as the pterygoid and temporalis muscles, undergo a modification similar to what occurs in the arms. As a result, zombies have an average bite force of well over a thousand pounds per square inch. Contrast this with a normal human's bite force of up to 300 PSI, and it becomes little wonder how zombies are able to tear into the toughest flesh and even grind bones with ease. But where the virus gives, once again, it takes away.
Zombie teeth remain maladapted for the intense pressure their newly strengthened jaws are capable of, causing them to crack and, within a few meals, fall out. This doesn't halt the zombie's comparative, however; they will continue to chew with only their exposed jaw bones until they too disintegrate.
Zombies do possess another adaptation for their new diet of flesh. Their saliva is abnormally high in tissue factor, a protein found in the saliva of many organisms, though in much smaller quantities. Interestingly, this is one reason the virus is able to spread, despite the fact that the infected attempt to entirely consume potential new hosts.
Anyone unfortunate enough to be attacked by a zombie may survive the encounter, as the coagulant nature of tissue factor stops major blood loss. Sadly, the agony of having major body parts chewed off and the subsequent relief at having survived the encounter is all in vain. Survivors will almost definitely contract the virus, invariably transforming them into zombies themselves.
But in contrast to common conception, zombies will seek out any kind of meat, not only human and especially not limited to the brain. They will, however, avoid necrotic flesh of any kind, and as such, I have never observed them to attack each other.
In any case, no matter how advanced their degradation, zombies still undergo normal bodily functions and must also ingest water, usually obtained from streams, puddles, and in early stages, even water bottles. The zombie digestive system itself remains largely unaltered, save for the gradual rotting away of its tissues and organs.
Unsurprisingly, zombies must also urinate, but thanks to a combination of poor circulation, brain damage, and kidney necrosis, they are physically incapable of doing so. This condition, known as urinary retention, causes the bladder to swell to a grotesque size, and eventually, it will burst.
The abdomen is then flooded with retained fluid, and it will remain there until a wound or ulcer perforates the abdominal wall. Indeed, the life of a zombie is one of numerous bodily horrors, and between their decaying bodies and reduced ability to absorb nutrients from their food, most zombies will truly die in less than a year's time. A direct contrast to the common notion of the immortal undead.
This claim of lifespan comes from direct personal observation, but if you happen to see a zombie in the wild, as it were, its age could be determined from the amount of decay apparent from its outward appearance.
Between months one and three post-transformation, zombie skin is mottled, often peeling, and dotted with open sores.
Between four and six months, the epidermis begins to split as underlying necrotic tissue bloats outward, and eyelids, lips, nose, ears, teeth, hair, nails, and sometimes fingers have all but rotted away.
By ten months, entire limbs are missing, as are most prominent facial features, and exposed bone is common. The eyes may have fallen out by this time, and the decay of the digestive system has led to a nearly unfathomable level of emaciation.
Needless to say, it is within the first couple of months when zombies are at their most dangerous, but while a single zombie poses little threat to a healthy human, the reality is that unless their numbers are kept in check by vigilant citizens, they usually don't hunt alone. Often drawn to the same sources of scent, zombies tend to congregate together, and though I have yet to determine the exact reason for this behavior, especially in early stages, it seems likely that it's the result of a residual and deep-seated human need for community.
Within a very short amount of time after an outbreak, herds of dozens of zombies can form. Surprisingly, zombies exhibit rudimentary forms of group hierarchy; the strongest of the herd eat first, and any who approach too early will be dealt with aggressively. Most surprising of all, there is evidence of larger groups working together to attack humans through very basic flanking maneuvers.

Myth and Legend

But of course, the main catalyst for hunting behavior is simple: the scent of flesh and, at least while their vision remains, movement. Indeed, even while feeding, zombies are relatively easily distracted; they may abandon a downed victim in order to pursue another, more mobile victim. Interestingly, this is another reason why HZV is able to spread. Victims are sometimes able to escape while their attackers' attention is diverted to another source of food.
Fortunately for us, zombie outbreaks tend to fizzle out relatively quickly, as zombies move slowly and cover little ground. Once they've exhausted the food supply in any given area, they often starve to death before many new zombies can be created.
One example of this can be found in the notable outbreak that occurred in 1863 in Vicksburg, Mississippi. During the famous Siege of Vicksburg, a major turning point in the Civil War, roughly 30,000 Confederate soldiers were effectively trapped inside the city by surrounding Union forces.
A couple of weeks into the siege, reports of erratic behavior from soldiers and civilians alike began to circulate, and Union troops reported gunfire from within the city limits, though not directed toward them. By the time the Confederate troops surrendered some 40 days after the siege began, Union soldiers were shocked and appalled to find decayed corpses littering the streets, and half-consumed victims lying beside them. This story is not widely known, but the reality of the matter is that in the Siege of Vicksburg, the U.S. narrowly averted a much worse disaster.
Fortunately, when it comes to defending yourself from a potential outbreak, knowledge is true power. Many who have heard the tales of the living dead have been erroneously taught that an attacking zombie can be felled by simple, direct damage to the brain, whether by firearm or impalement. In reality, zombies are able to withstand a shocking amount of trauma, both to the body and brain.
Destroying certain parts of the brain may disable certain functions, such as the thalamus and cerebellum, which may cause blindness and loss of balance respectively, but the only thing that can quickly stop a zombie is to severely damage the brainstem. The most effective method is to sever the head completely, but if time isn't a factor, though it usually is, zombies can be killed by damaging any part of the body with enough force.
After all, they still require their internal organs, such as intestines and lungs, to function. However, as indicated previously, zombies are able to recover from even a severed spinal cord, so aiming for anything other than the brainstem is a risky endeavor.
One myth commonly associated with zombies is that their heads continue to live even after decapitation. Given their resilience, the idea isn't terribly far-fetched, but the reality is somewhat less sensational.
Following decapitation, zombies may continue to exhibit movement, such as blinking and even biting, for up to a full minute, at which point all activity ceases. Still, this is quite a bit longer than in humans, which may remain conscious for up to 30 seconds following a beheading.
This difference is likely caused by additional oxygen in the zombie's slow-moving blood, though increased neural resilience may play a factor as well.
And so, once again, dear reader, I must thank you for following my findings and, admittedly, ramblings thus far. If you have found even a glimmer of belief within yourself during this presentation, I implore you to seek me out. If you are unable to do so, then I have but one humble request: do not let the sun set on this work.
Though outbreaks have so far been limited to areas of the world that our modern culture finds easy to dismiss, I can assure you that unless precautions are taken, it's only a matter of time before a convergence of outbreaks becomes catastrophic. At that point, the loss of life will be unstoppable, and we could find ourselves trapped inside rotting flesh, doomed to wander the earth until our decaying bodies fail, returning us to the dust from which we came.

Watch the video here:

Related condition: Human Zombism Virus