The Infected aren’t really zombies: They’re not the risen dead. These are people infected with a mutated virus that activates the rage centers in the brain. It also causes other biological systems to go crazy. Get more after the jump.

Infected With A Virus

In general, rabies is the most common virus used. It’s known for its ability to destroy the brain, create aggression and spread easily through body fluids.

Mad scientists prefer to use a virus because of their ability to replicate quickly within the body and the slow immune response to attack. Essentially, it’s easier to ‘get a hook’ in the body.

How The Virus Changes Body Chemistry

The Infected are man-made monsters. Mad scientists changed a common virus and turned it into a monstrosity. They did this to make shock troops for the military.

Or it was an unintended consequence. Scientists use mutated viruses to fight cancers or other dire conditions. Sometimes, a mutation happens.

Attacking The Brain

First and foremost, the virus goes after the brain. That’s where behavioral centers lie. The virus will attack the more instinctual areas, like the limbic system. It controls things like the need to feed, mate, fear or fight. It’s also called the basal ganglia.

The virus wants to ramp up the biochemical reactions in this part to overwhelm your learned behaviors or controlled actions.

Once overwhelmed, the infected person is just a raging beast, looking to attack anything in sight.

Biochemical Changes Ramp Physical Abilities

The virus has a high viral load per drop of body fluid. It’s the viral load that lets it overtake the host body with a few minutes. It also multiplies rapidly after it enters the blood stream. One bite will introduce enough virus to create another infected person within minutes.

Once inside your body, the virus primarily attacks the brain, but it also attacks the endocrine system, which makes adrenaline and cortisol. Both hormones help the body’s stress response and the fight-or-flight response.

As the body tries to fight off the virus, your temperature and blood pressure increases to unsustainable levels. Your temperature will rise above 104° and your blood pressure will surge over 180/120.

The adrenaline surge will increase your endurance, strength and speed. It will also shut off fatigue hormones, so your body won’t tire quickly. This lets the infected person continue to attack normal humans without resting.

Unfortunate Side Effects

The body will eventually fail from the biochemical reactions gone wild. The most likely side effect is a stroke. Increased blood pressure and vein constriction from high cortisol and adrenaline will rupture the vein walls in the brain. That will kill the infected person in seconds.

Also, the elevated body temperature will begin to kill brain cells, leading to an even more erratic and violent behavior in the host. But the stroke will likely kill the person first.

Other organs will start to fail from the cytokine storm, an immune response that attacks anything foreign in the body. It will overwhelm the organs’ functions and leads to certain death.

In a nutshell, the virus will kill its host within a week.

What To Do If You Encounter An Infected Person

The Infected come in waves like runner zombies. It’s not just one, but an army of running, gnashing, clawing and biting zombie-like people.

But they’re still people with all our weaknesses.

That means guns, knives, baseball bats and other weapons work well. You still have to avoid contact with an Infected’s body fluids. One drop of their blood on an open wound will transform you into this monster.

Running away (the usual advice) may not work because of their numbers. If you can lock yourself away and wait out the Infected storm, that may be your best option.

But be careful. It doesn’t take much for the virus to re-activate. Even if the Infected’s body is dead. The virus is still viable.