Vodou, Vodun, or Voodoo was bought to America by slaves about 400 years ago. Now to answer your question Vodooo is a west African tradition. Those of us who practice Voodoo is called Voodooists . Though of course you may hear different wordings of "Voodoo." For example you may hear some one say Haitian Vodou, West african Vodun, or lastly Louisiana Voodoo. By the way just to note, this is actually a question someone asked me a few days ago: " Is voodoo only for Africans or colored people in general." Which is a good question but no, of course over time other people began to take part in it, so if you were also curious, and on that note I greatly hope I was able to clarify.
Just to kind of clarify a bit on what I just said Voodoo is known to have gone back 5-6000 years ago in Western Africa, the religion however did come to America with Haitian and other West African slaves, which indicates it has spread before it's arrival in America.