True Virus

The Progenitor Virus was the first mutagenic virus ever discovered. It would become the basis from which the Umbrella Corporation's most successful mutagenic viruses would stem. It was discovered on December 4th, 1967 by James Marcus, Edward Ashford, and Ozwell E. Spencer.

The first subjects were Lisa Trevor and her mother, Jessica, who were administered the virus on November 10, 1967. Jessica was administered the Type-A variation, which her body successfully fought off. Lisa was administered the Type-B variation and underwent a strange mutation. She became extremely aggressive and even killed and ripped the face off her own mother.

James Marcus then combined the Progenitor virus with leech DNA, creating the T-Virus. William Birkin and Albert Wesker assassinated Marcus and continued his research at the Spencer Mansion. Here, William experimented on Lisa Trevor with new variants of the T-Virus on orders from a head Umbrella researcher. These experiments led to the G-Virus, discovered by mixing the Type-B Progenitor in Lisa's body with the NE-a parasite.

Umbrella researchers asked themselves: "What if a heavily-infected host could continue to still be mobile, and what if the host could continue to infect others, as well?". This idea would eventually give birth to the T-Virus.

After the development of the Progenitor virus, three men would finally succeed in the creation of the T-Virus on December 4th,1978 after combining it with leech DNA. These men were James Marcus, Albert Wesker, and William Birkin.

The T-Virus would serve as the basis of most of the other viruses developed by the Umbrella Corporation, such as the T-Veronica Virus and the NE-T Virus.

William and Albert assassinated Marcus and took his research for Umbrella. With their experimentation with the Ebola Virus, William Birkin combined the original T-Virus with the Ebola Virus to create a more suitable and dangerous virus that was used to create the Tyrants. The Progenitor virus and original T-Virus have been used for many purposes as stated above.

What the T-Virus does is kills any living mitochondria and replaces the dead ones with itself. The virus then combines with other cells to produce energy. The energy produced is just enough to power the motor neurons and the basic lower brain functions. Not only that, but this bypasses the entire circulatory system, which makes the heart and lungs redundant systems that can be disposed of.

However, the T-Virus can only properly function by consuming the cell in order to produce its energy and to divide via mitosis to spread around the body. This slow breakdown of cells leads to the necrotizing effects seen on most BOWs. The virus also incorporates itself into the host's RNA, which substantially alters it. This is why creatures, such as bees and spiders, only have very minor mutation, such as increased size, when compared to the human mutation caused by the virus. This is due to their lower stance in the evolutionary chain.

Should the human host be alive at the time of T-Virus infection, all higher brain functions are destroyed as the virus simply dissolves away the frontal lobes. This leaves only the telencephalon, better known as the cerebrum, to govern behavior. This leaves the infected host with a very animalistic behavior. As the virus spreads, it damages the hypothalamus. This produces a massive flood of neurotransmitters, enzymes, and hormones such as norepinephrine and dopamine. These effects, combined with the painful symptoms of the infection, induces a psychotic rage, persistent hunger, and increased aggressiveness in those infected.

Should the human host be dead at the time of infection, only enough energy is produced to power the lower brain functions. These functions are responsible for the most primal instincts, such as walking and eating.

In either case, their late-stage appearance and behavior are characteristics of their name-sake, that of the zombie.

Should a late-stage human host be rendered unconscious, the body will lay in a dormant phase appearing to be dead. In actuality the host is rapidly mutating due to the T-Virus becoming hyperactive. Within the timeframe of an hour, the decayed skeletal and muscular system is reconstructed into a stronger and more durable form, development can be seen of sharp canine teeth and razor claws, fresh blood seeps into remaining skin giving it a reddish hue, advances in decomposition, and intact eyes become a bright white. Umbrella researchers at the Arklay Laboratory have dubbed this stage as an V-ACT, commonly referred to as a Crimson Head. The brain is then jolted back to consciousness with a slight but important increase in intelligence, and large increase in agility and aggressiveness. As a consequence of this rapid mutation, cellular breakdown hits a critical point where the host cannot regenerate properly any longer and can effectively be killed permanently, given enough damage.

Diferences to the T-Virus The G-Virus is quite different to the T-Virus in terms of action and transmission. While both viruses have the characteristic of inciting mutation in infected organisms, the similarities end there. The G-Virus has none of the necrotic properties of the T-Virus, and as such, host organisms do not decompose (the characteristic rotting of the zombies).

The G-Virus also acts exponentially faster than the T-Virus, with William Birkin manifesting considerable physical mutation mere seconds after infection. Apparently, direct injection of the virus is nigh incurable, as it acts much too fast for a vaccine to be effective. Infection by parasitic infestation, however, can be controlled much like the T-Virus, with a vaccine being effective if administered during the initial stages of infection, before the larva can gestate. While the T-Virus' effects on long term, controlled exposure are well documented(Tyrant, the Hunters and the Lickers being examples), the effects of such exposure to the G-Virus are unknown, as there was no testing in this field done before the Raccoon City incident. However, results of such manipulation of the virus COULD be seen in future instalments off the series, since both HUNK and Ada Wong were able to procure samples of the virus for Umbrella and Albert Wesker, respectively. However, if the effect of said exposure was similar to the T-Virus and T-Veronica virus, such bioweapons would theoretically be the absolute deadliest creatures ever made by Umbrella. Birkin himself, an accidental G-mutant, was more powerful and deadly than any creature created with the T-Virus on purpose. The effects of the G-Virus on non-human hosts is unknown, but they are probably just as radically powerful and unstable as their human counterparts in comparison to the T-Virus.

The G-Virus greatly increases the carrier's metabolism, accelerating cell duplication and revitalization of dead cells at the cost of higher brain function by continual destruction of mitochondria in neurons, causing the infected person to degrade to sub-human levels. The carrier exhibits animalistic behavior, loss of moral reasoning and become driven by self-preservation. Ultimately, carriers become creatures simply dubbed G-Mutants.

Stage 1
bears the greatest resemblance to the original, though larger and more muscular. The right arm (where Birkin injected himself and where he was sprayed with several sub-machinegun rounds) is considerably swollen with muscle, and a large tumor/eyeball has developed in a flap of flesh there. Supposedly, this is where the G-larvae are developed prior to implantation. (Beyond the swollen arm and the large eye, this form also bears resemblance to a T-virus zombie, although the part of the body that still looks human is not as rotted as a zombie.)

Stage 2
causes the carrier's head to move forward and downward, being absorbed into the left half of the chest, and the fingers of the right hand are replaced with massive blade-like claws of bone. Practically vestigial third and fourth arms develop on the left half of the body and a new rudimentary head grows to take the place of the old one. On top of that, an entirely new brain, far more animalistic and vicious, is added, replacing Birkin's true brain.

Stage 3
is perhaps the least grotesque. The carrier has shed all of its skin, revealing its musculature, and its two primary arms have developed deadly claws. A set of smaller, functional arms (resembling its original human ones) have grown and the rudimentary head from the prior stage is now more human-like, encased in a shell of bone and sporting the lipless grin favored by most of the Tyrant models. A secondary, smaller eyeball/tumor has developed in the left upper thigh. This form is the only one that has bilateral symmetry, and it resembles closely a demon.

Stage 4
goes from bipedal to hexapodal; the top half of the skull elongates whilst the lower jaw splits in half vertically and sinks into the chest, transforming the entire chest into a vertical mouth lined with giant fangs. Its six limbs now serve as legs, and this stage is extremely fast and agile, and the jaws now have the main function of impaling its enemies.

Stage 5
is the most grotesque of all. After extreme damage and abuse to the carrier, the carrier has become a shapeless blob of flesh, fangs and tentacles, slowly dragging itself forward. It seems that by this stage, the G-Virus has evolved continually by merging with the beings it has devoured to sustain its high regenerative powers, and multiple organs sprout from the main blob. Killing this creature permanently requires extreme measures, such as a truly massive conventional explosion.

A DNA match can only be achieved by a blood relative of a G-mutant becoming impregnated. The embryo begins to pupate and assimilate the host body turning them into what can only be believed to be a mutant of immense strength. Sherry Birkin was impregnated by her father, but the parasite was destroyed with an experimental anti-G-Virus vaccine, codenamed DEVIL, before mutation could occur with help from her mother Annette Birkin and Claire Redfield.

Though what the G in G-Virus means is never explicitly stated, given that the antidote for it is called DEVIL, and the personality of William Birkin, it is a fair guess that G stands for God.

The G-Virus is also much harder to transmit from one organism to the other. While the T-Virus can be transmitted by body fluids, direct attack from an infected organism, or even water, the G-Virus can only be transmitted by direct injection or active insemination of a parasite into the prospective host by a G-mutant, and G-mutants (as evidenced by Birkin and his spawn) instinctively attempt to reproduce. In this manner, G-Virus mutants act much more like living creatures than those infected with the T-Virus. While T-Virus infection can be considered accidental (as the host does not actually mean to infect its victim), G-mutants actively attempt to perpetuate their species. This has the frightening implication that, while the T-Virus is infinitely more contagious, a G-Virus epidemic would be nigh uncontrollable and actively hostile to humanity, as G-mutants would seek to reproduce over any other instinct.

The G-Virus also acts exponentially faster than the T-Virus, with William Birkin manifesting considerable physical mutation mere seconds after infection. Apparently, direct injection of the virus is nigh incurable, as it acts much too fast for a vaccine to be effective. Infection by parasitic infestation, however, can be controlled much like the T-Virus, with a vaccine being effective if administered during the initial stages of infection, before the larva can gestate. While the T-Virus' effects on long term, controlled exposure are well documented(Tyrant, the Hunters and the Lickers being examples), the effects of such exposure to the G-Virus are unknown, as there was no testing in this field done before the Raccoon City incident. However, results of such manipulation of the virus COULD be seen in future instalments off the series, since both HUNK and Ada Wong were able to procure samples of the virus for Umbrella and Albert Wesker, respectively. However, if the effect of said exposure was similar to the T-Virus and T-Veronica virus, such bioweapons would theoretically be the absolute deadliest creatures ever made by Umbrella. Birkin himself, an accidental G-mutant, was more powerful and deadly than any creature created with the T-Virus on purpose. The effects of the G-Virus on non-human hosts is unknown, but they are probably just as radically powerful and unstable as their human counterparts in comparison to the T-Virus.

Alexia determined that in order for a host to accept the T-Veronica strain, it must be kept in cryogenic sleep for a long period while the virus incubated. Alexia implanted the virus inter her own body and put herself in cryogenic sleep for fifteen years. In 1998, Alexia awoke, her body having accepted the virus with no deterioration of her intelligence. In her first mutated form, she keeps a humanoid figure (with a different appearance), but gains the ability to turn her blood into flames. In her second mutation, she resembles a giant queen ant and gains the ability to reproduce imperfect larvae. In her third and final form, she becomes a flying insect with four wings on her back.

Lesser creatures resulting from T-Veronica virus exposure also exhibit a sort of "hive mind", becoming subservient to higher intellect hosts, as evidenced by Alexia's control over the huge T-Veronica virus worms released after her sleep, as well as the different insects spawned by her subsequently. This is probably a side effect of the virus's origin as being spliced from the Progenitor Virus and ant DNA. In this manner, the T-Veronica virus, although of completely different origin, exhibits similar characteristics to Las Plagas, as Plagas infected beings were all subservient to Osmund Saddler, who'd be the "queen ant" of the Plagas, as it were.

Although not specified anywhere in-game, the T-Veronica virus is apparently more stable in terms of transmission than both the T- and G-Virus. While T-Veronica mutants can reproduce(as evidenced by Alexia's creation of many subservient insects), they apparently cannot infect other creatures. The T-Veronica virus seems to be only transmittable through direct injection.

It first appeared in Resident Evil: Dead Aim. A sample of this virus was stolen by Morpheus D. Duvall, a former researcher from the Umbrella Corporation who injected himself with the virus after being gravely wounded by Bruce McGivern, causing him to mutate into a Tyrant T-092.

Due to years of concealment, the Plagas became fossilized in the rocks below Salazar's castle. However, the Plagas were still alive at the microscopic level in spores within the fossils. The miners that were excavating the site accidentally inhaled the spores while excavating which caused the revival of the parasites within their bodies. Since then, Saddler developed Plagas eggs by growing spores and having them mature, and then injecting his followers with the parasite.

Albert Wesker, who is now apparently running the Umbrella Corporation which had gone underground after the events of Raccoon City, had tasked Ada Wong with retrieving a sample of the Plagas in order to help reestablish Umbrella after learning of the creature by messages sent by Luis Sera that were intercepted. He previously had sent in a new operative, Jack Krauser, to get inside Saddler's inner circle but later sent in Ada after it appeared Saddler did not trust Krauser. Ada ended up betraying Wesker unbeknownst to him in the game, as she gave the Plaga sample she stole to a group she refers to as "the Agency".

Besides influencing the actions of those they infect, Plagas leave several distinct side effects. These include, but are not limited to: coughing up blood, convulsions, sudden unconsciousness, hallucinations, veins and arteries show throughout skin and discoloration of the iris – usually to a reddish color.

The parasites also have a high adaptability rate, as they can possess other kinds of organisms besides humans. (Ramon Salazar uses Plagas-infected wolves as guard dogs in his castle.) In addition to the Ganados, Saddler and his men also created several kinds of mutant creatures with Las Plagas such as El Gigante, the Regenerators, Novistadors, and the U3 as a result of genetic experimentation with the parasites and human specimens.

All of the members of Los Illuminados, including Saddler himself, have Plaga parasites implanted into their bodies. However, the ones used by him and his top underlings (Bitores Mendez and Salazar) are that of "queen plagas" that can control the plagas through sonic signals, thus controlling the Plagas which control the humans.

Except for manifesting when sufficient trauma is induced on a host, Plagas have no true mutagenic effect on their hosts' body. While the Plaga infecting the Ganados and Colmillos can manifest and mutilate the body of their host, they do not actually induce any significant mutation or physiological change like Umbrella's myriad viruses do. However, other creatures like the Novistadors and Garradors do exhibit mutation, but this is the result of actual genetic manipulation, not an effect of casual infection. However, it is the fact that victims exhibit no outward signs of infestation which makes the Plagas a very dangerous threat, since it is much more subtle and invasive than Umbrella's viruses. The ability to exert control on them also makes them ideal as weapons, a fact Albert Wesker is probably going to take advantage of, now that he has a sample of the Plagas. It is a frightening thought to imagine what a combination of Plagas and one of Umbrella's viruses would be like, but it probably would result in a much more powerful parasite, while at the same time more control could be exerted on the host.

Luis Sera, a researcher who betrayed Saddler, built an operating machine (the Plaga Removal Laser) which produced this kind of radiation after extensive research regarding how the Plagas might be removed. Leon and Ashley, who had Plagas implanted into their bodies, used the machine to eliminate the Plagas, both managing to survive the operation.

Las Plagas are also very vulnerable to bright lights. They will only emerge from their hosts at night, and can be instantly killed by throwing a flashbang grenade at them