Although it wouldn't surprise me if someone had some in a private collection somewhere in the states. I would think they would be rather expensive to properly care for.
A lot of wild swine are, even if though they may not intend to be. Used to work with Wart Hogs as a keeper, would never want them outside the zoo environment (safety doors, etc.). I also knew a keeper who was injured by one of our Red River Hogs and have talked with keepers in who worked with Babirusa, they say they are pretty unpredictable and skittish.