And I believe most Haitians came from that part of Africa.
Witchcraft is part of African traditional medicine and has to do with evil spirit.
It is found everywhere in Africa under different forms and names. It is probably as old as humanity. I also suspect that the collage of names and words used in Voodoo comes from the Pigeon English developed by Africans from many different ethnic groups who were living together in slave camps in West Africa and then being taken to the Carribean. This might also account for similarities to a wide range of indigenous religions of West Africa. Basically, many people from different backgrounds were forced to live together, so they adapted as best they could and developed a religious institution from pieces of the different groups represented.