Chapter 22: Research Findings

The relocation of the base was finally complete. The Tiger Squad had spent far more time and energy than anticipated to accomplish the task. Undeniably, zombies that had begun using tools were far more difficult to deal with than before.

The situation grew increasingly dire. Although the base had already informed several survivor camps—who had established communication links with the base—about the latest developments regarding the zombies, these groups clearly did not take the warnings seriously enough. Soon, these camps sent out distress signals, requesting assistance from the base to help locate their missing field personnel.

In the conference room, the members of the Tiger Squad, fully geared and ready to depart, had just finished receiving their mission briefing when Dr. Mei burst in hastily.

“Everyone, sit back down,” she commanded in an unequivocal tone. “No one leaves until I’ve finished speaking!”

When a human is attacked by a zombie, the Z-type enzyme enters the bloodstream through the wound. White blood cells, which bear many responsibilities including engulfing foreign invaders and producing antibodies, immediately spring into action.

Once the Z-type enzyme infiltrates the body, the white blood cells desperately engulf the invader, only to become infected themselves and produce more Z-type enzyme. This triggers symptoms of zombification—high fever, convulsions—until the enzyme completely overpowers the white cells and gains control of the brain. At this point, the infected individual dies.

Subsequently, the Z-type enzyme reanimates the deceased, though this is not resurrection in the true sense. First, the enzyme only controls a small portion of the brain, leaving large areas that even humans have not fully developed untouched. This suggests that zombies possess only the most basic animal instincts. Second, the human body is a complex machine; once cells are deprived of oxygen, they perish. The blood within zombies evidently lacks the ability to transport oxygen, a fact corroborated by the pervasive stench of decay emanating from them.

Zombies maintain this semi-decayed state because the enzyme facilitates it. Saprophytic bacteria cling to their bodies, providing a continuous energy source to the Z-type enzyme. This explains why zombies do not simply turn into puddles of putrid liquid over time, nor starve to death from lack of food.

There is reason to believe that zombies do not require sustenance to survive indefinitely, so long as the Z-type enzyme remains active within them. Dr. Mei and her medical team have conducted extensive research into the eating habits of zombies.

Brain scans reveal that when zombies detect a target, a mysterious region of their brain becomes unusually active. This heightened state persists long after the target disappears, while the area responsible for hunger signals remains completely unresponsive.

Many humans become zombies after being bitten, but reports from the Tiger Squad’s field operations have never found a corpse that had been completely consumed—a fact that supports Dr. Mei’s observations.

If zombies attacked purely out of primal hunger, then after a living person was surrounded and devoured, nothing would remain but a skeleton, not a newly formed zombie. Therefore, the intent behind zombie attacks likely differs from the initial assumption of feeding. Based on the data, Dr. Mei reached her own conclusion.

Rather than predation, zombies’ assaults appear to be a mechanism for releasing the Z-type enzyme. Whenever personnel approach a test subject, the zombie secretes copious amounts of saliva containing the enzyme and enters a frenzied, aggressive state. When left alone, this behavior scarcely occurs.

Thanks to the remains of a “Crusher” zombie brought back by the Tiger Squad, Dr. Mei was able to compare ordinary zombies with their evolved counterparts. The results showed that the Z-type enzyme within Crushers was identical to that in common zombies, but their DNA structures differed greatly.

Crusher DNA contained many more gene sequences, seemingly derived from multiple individuals—a phenomenon impossible in normal humans. The only plausible explanation is that Crushers acquired these genetic fragments through some other means.

To test this hypothesis, Dr. Mei conducted a bold experiment: feeding. After zombies bite humans, the victim’s blood and muscle tissue enter the zombie’s digestive system, possibly allowing the zombie to obtain new gene fragments.

Dr. Mei introduced drops of her own blood into the test subject’s mouth to observe whether the zombie would indeed acquire genetic material this way and evolve.

Unfortunately, the experiment yielded little progress. Although new gene fragments appeared in the subject’s cells, no outward changes were observed—likely due to insufficient time or quantity of genetic material—contradicting the anticipated rapid evolution.

Zhao Qiang, the sole individual who was attacked by zombies yet did not succumb to zombification, became a key focus of Dr. Mei’s research. During the battle at Mount Yuelu, Zhao was bitten by a zombie rat, experiencing severe symptoms—unconsciousness, relentless fever, convulsions.

When everyone believed Zhao was lost, a miracle occurred, sparking great interest in Dr. Mei. She surmised that Zhao’s body must contain a unique antibody capable of resisting the Z-type enzyme. If this substance could be extracted and turned into a vaccine, humanity might finally glimpse the dawn of victory.

Analysis of Zhao’s blood revealed not only his, but that everyone in the base possessed a special protease—N-type enzyme—whose molecular structure closely resembled the Z-type enzyme. This enzyme could neutralize the spread of Z-type within the human body.

Regrettably, the N-type enzyme’s activity was far weaker than the Z-type’s, consistently losing the biochemical battle. Once bitten, the flood of saliva carrying Z-type enzyme through the wound spelled doom.

Zhao’s survival owed much to the nature of the zombie rat’s attack. The high-speed spinning of the rodent’s teeth caused the enzyme-laden saliva to be flung away by centrifugal force, only a minuscule amount entering Zhao’s body—thus sparing him from infection.