Of course it is! The zombie myth/phenomenon (actual zombies, not movie zombies) originated from the voodoo rituals of West Africa and Haiti. Romero and others have just taken the voodoo stuff out and left in the living dead....usually offering up their own explanation in whatever book or movie they're writing.
If you dug the movie, you should check out Wade Davis' book. It's a fantastic read.
Hence why I said per-se. Awesome movie that involves zombies, but in my opinion not the typical zombie movie. The zombies themselves are made to be more of a plot device than the nemesis of the standard zombie movie. SatR is more of a drama than your typical horror genre zombie flick.
And I reiterate. I really need to get myself a copy. It is far superior to the Indiana Jones movies in my opinion.