Let me channel Lydia Kang here:
1.) Half of the world's population is already infected ...
with toxoplasmosa gondii
a parasite that seems to devote its entire existence to being terrifying.
This bug infects rats, but can only breed inside the intestines of a cat. The parasite knows it needs to get the rat inside the cat
so the parasite takes over the rat's brain, and
intentionally makes it scurry toward where the cats hang out. The rat is being programmed to get itself eaten, and it doesn't even know it.
Humans and rats aren't all that different; thats why they use them to test our drugs.
All it takes is a more evolved version of toxoplasmosa, one that could to do us what it does to the rats.
So, imagine if half the world suddenly had no instinct for self-preservation or rational thought.
Oh, we call that adolescence.
2.) Mad Cow Disease:
It attacks the cow's spinal cord and brain, turning it into a stumbling, mindless attack cow.
And, when humans eat the meat ...
How it can result in zombies:
When Mad Cow gets in humans, they call it Creutzfeldt-Jakob disease. Check out the symptoms:
•Changes in gait (walking)
•Lack of coordination (for example, stumbling and falling)
•Myoclonic jerks or seizures
•Rapidly developing delirium or dementia.
How many members of Congress does that describe?
So, imagine such an evolved disease, which we'll call Super Mad Cow getting a foothold through the food supply.
Say this disease spreads through blood-on-blood contact, or saliva-on-blood contact. Now you have a Rage-type virus that can be transmitted with a bite.
Just like the movies. With one bite, you're suddenly the worst kind of zombie:
A fast zombie.
As seen in ...
Laboratories around the world.
What is it?
You know all that conversy out there about stem cell research?
Well, the whole thing with stem cells is that they can basically be used to re-generate dead cells.
Particularly of interest to zombologists like ourselves is neurogenesis, the method by which they can re-grow dead brain tissue.
You can see where this is going.
Science is already able to re-grow the brains of comatose head trauma patients until they wake up and walk around again.
Couple that with the new ability to keep a dead body in a state of suspended animation
so that it can be brought back to life later, and soon we'll be able to bring back the dead, as long as we get to them quickly enough.
That sounds great, right?
Well, this lab dedicated to "reanimation research" (yes, that's what they call it) explains how the process of "reanimating" a person creates a problem.
It causes the brain to die off from the outside in. The outside being the cortex, the nice part of you that makes humans human.
That just leaves the part that controls basic motor function and primitive instincts behind.
So, you take a brain dead patient, use these techniques to re-grow the brain stem, and you now have a mindless body shambling around,
no thoughts and no personality, nothing but a cloud of base instincts and impulses.
Think about it. Under every legal system in the world,
all rights and responsibilities are terminated at death.
All it takes is someone with resources and a need for a mindless workforce of totally obedient slave labor.
How long until somebody tries this? We're betting somebody in the world, maybe North Korea, will have a working zombie by Christmas.
For further scientific scariness:
See 7 year old Victor Standish versus zombies in a Detroit infested with them!
12 minutes ago