I was really interested in Haitian zombies after we discussed them in class, and I found a few articles about them. Apparently, zombie-ism has been prevalent for hundreds of years. Voodoo practitioners poison someone using the poison of a pufferfish. This poison causes the person to become slowly more lethargic until their pulse slows and they appear dead; however, they are fully aware the entire time. The "zombies" will continue to act like robots unless they eat meat or salt. Eventually the zombies become incoherent and actually do die. There are even rumors that many of the plantation workers in Haiti were zombies and that Papa Doc Duvallier's army,the tonton macoutes, was made up of zombies. Haitian law states that this practice of zombie-ism is considered murder.
Unfortunately, I have no idea how reliable this source is,