For this I have done some research into some deadly parasites and how with a few minor tweaks we could be facing our own problem with corpses that will not stay down. A parasite is an organism that lives off another and does whatever it takes to survive; some times this comes at a deadly cost to the host involved. After reading information on this I thought it would make sense to list a few examples of parasites that are close to being something of a problem like this. Three of the parasites I have read about that I am going to talk about are: Toxoplasm gondi, Cordyceps fungi, Ampulex compressa.
Toxoplasma gondi is also known as the mind-control bug. This bug infects rodents and removes their fear of cats. This one rarely does anything to the cats involved but when it comes into contact with humans it can have cause some strange behaviors. These parasites can slow our reaction times and the infected humans are more likely to end up in a car accident.
The second one I am going to talk about is Cordyceps fungi, better known as the head-splitting fungus. Imagine that something infiltrating your body and controls your behavior and when it is done it bursts out of your head. When the head bursts open that is how the parasite is passed and that cycle starts again.
The third one I am going to mention for this is Ampulex compressa; the zombie wasp. This one preys on cockroaches, and turns them into zombies. They do this so the infected cockroach will feed their young. The sting is aimed directly into the roach’s brain and disables the escape reflex. Then the roach is lead to its death.
So a combination of some of these traits with a few twists and something that would take over a human body and mind. It could turn the living into undead with a bite, or infection some how passed on. This could cause the need for zombies to “feed” like we have seen time and time again in the movies.
Further information can be found here.