In the graphic novel 28 Days Later: The Aftermath, two Cambridge University scientists named Clive and Warren were trying to isolate the specific neurochemicals that cause anger and excessive aggression in humans in order to develop an inhibitor that regulates anger control issues.
Warren decided that it was waste of time to experiment on volunteers from the school for the experiment because Cambridge students obviously didn't have uncontrollable rage. So he manages to get a contact at a police station to give him a violent criminal as a test subject. There was a problem with the delivery system. The injections were too diluted so Warren increased the dosage. However, the inhibitor still had no effect and when the test subject was about to attack Warren and Clive, Warren was forced to kill him. He then immediately decided they would experiment on chimpanzees, as Clive had been suggesting.
As Warren and Clive were burying the criminal, Clive sneezed - giving Warren an idea. They had known that delivering widespread with a pill wouldn't do, neither would an aerosol. He decided that they should use a contagion as a delivery system. He located a certain genome in a strain of the Ebola virus. Using this new delivery system, the two exposed a chimpanzee to the inhibitor. However, the inhibitor mutated. In the chimpanzee, it had the opposite effect of what is was supposed to do. That is, it caused the chimpanzee to be full of uncontrollable rage. Warren had "created a rage virus."
Clive was so disgusted by this that he quit. He later informed an animal rights eco-terrorist organization about the experimenting on animals and then shot himself. A group of those eco-terrorist would later break into the lab and free the infected rage filled chimpanzee. That chimpanzee attacked and infected them and Warren. From them, the Rage virus spread throughout the island of Britain.
After the virus enters the characters' bloodstream, the virus would be usually very quick to manifest itself in the victim's behavior (see below), from the films it is shown that only 10 to 20 seconds is required for the virus symptoms to become noticeable though infection time is possibly determined by the amount of infected blood that has gotten into the bloodstream and the overall mass of the person in question. As the virus overwhelms its host, they twitch madly in an almost spasm manner. This is a sad time for the human in hand as they cannot control the state they will live or die in after the Rage virus takes over. The virus can also pass through bodily fluids and has an almost 100% communicability rate, though it may be noted that some characters posses a hereditary immunity, allowing them to become infected with the virus without exhibiting any of its usual symptoms (save the bloodshot left eye). These characters remain carriers of the infection, and can transmit it through blood-saliva contact and saliva exchange.
Danny Boyle has stated that in the films, primates are the only animals that can carry the virus (a fact that is further touched upon in the second film in the series).
Symptoms of Infected CharactersEdit
The Rage virus does not directly cause the death of its host, but because the host is solely focused on infecting or killing the uninfected it causes those infected to become disinterested in self-nourishment, which will eventually cause death by starvation. Since the virus causes those infected to act with no regard for self-preservation they will not act to evade mortal danger, such as fire or chemical gas.
The Rage virus causes its hosts to permanently enter a primal state of murderous rage and attempt to spread the infection or kill the uninfected above all else, even self-preservation. The Infected are reduced to an animalistic state of permanent hostility and aggression, driving them to attack non-infected with no concern for their own safety and no moral or other inhibitions that could control their actions and behaviour. In this state of permanent and extreme psychosis, the brain is continuously pumping adrenaline into the host's system, giving the Infected huge powers of endurance and super-human strength, but at the same time placing enormous stress on their metabolism, which alongside their disregard for their own safety, leads to eventual death through physical exhaustion, coma and/or starvation. The Infected experience spasms in the extremities, and their irises become blood red. They also vomit copious amounts of infected blood as well as violently gibbering for reasons unknown.
In 28 Days Later: The Aftermath, a character wonders how the Infected are able to track the uninfected down and know not to attack each other. After seeing them sniff the air he concludes that they are attracted by the smells of the uninfected, or maybe just able to smell something other than their own rotten flesh. Disease, anxiety, even rage affects the way people smell. In addition, the Infected have a very pungent odor. Even though the survivors hadn't bathed in weeks, they were still saturated with deodorants and shampoos. The Infected's sense of smell is how they find the uninfected.
In the film 28 Weeks Later it is shown that there are certain people who, while not immune to the virus in the truest sense, can carry the virus without any physiological or psychological changes, except for one - a reddening of parts of the left eye. These people are classified as "asymptomatic carriers" (possibly a mistake by the scientists in the film, as the eye change is technically a symptom). A carrier will not become uncontrollably violent like other Infected and will otherwise be unaffected by the presence of the virus. A carrier can, of course, still spread the virus as they still carry it in their blood and saliva. The audience is led to believe that whatever traits the carrier's biology uses to resist the full effects of the virus may be harnessed to develop a cure or vaccine.
- See Main Article: The Infected
The Infected are distinct from almost all cinematic zombies; they are not the reanimated dead. Also, films such as the Living Dead, Return of the Living Dead, and Resident Evil series portray zombies as creatures that desire to consume living flesh. By contrast, the Infected chase uninfected with the simple desire to either kill or infect them in a fit of rage. This characteristic is seen most clearly when the Infected make the use of tools to aid their killing of uninfected. For example, Don used Major Scarlet Ross's own rifle to beat her to death. Another example was when Don inflicted extreme pain and cruelty upon his wife by forcing his thumbs through her brain via the eye sockets, which suggests some sort of sadistic thought process. It is unknown if this desire to cause suffering is why a specimen will sometimes interrupt their attack to intentionally vomit blood into the face of their prey. While somewhat uncommon, this method has been known to quickly transform the human into a fellow Infected attacker.
Another change would seem to be that adrenaline is constantly being produced and utilized by the infected body, as even days after the change, an infected specimen can perform display extraordinary feats of strength, agility, endurance (especially in pursuit of the unifected), and also to ignore wounds such as explosive amputation of limbs and even immolation.
And while the Infected will attempt to bite their victims, it is usually as a means of either infecting or killing them (often by biting into the main arteries in their neck). They are not shown to ingest any organic material, and probably do not feed. Since Rage-infected specimens are still living human beings, they can be killed using means that are fatal to uninfected, as well as succumbing to starvation, unlike zombies.