Where did the Haiti cholera outbreak come from?

A Haitian protester in Port-au-Prince last year spray-paints a wall, equating the UN mission in Haiti (abbreviated here as MINISTA) with cholera.

 From the NPR health blog last week reporting on a paper published on June 18 2012 in The Proceedings of the national academy of Sciences (Genomic diversity of 2010 Haitian cholera outbreak strains)

Most researchers currently believe that United Nations peacekeeping soldiers introduced cholera to Haiti in October of 2010.
After all, Haiti hadn't recorded cholera for as long as a century, Nepal had experienced a cholera epidemic in the months preceding the soldiers' arrival, and the Haitian and Nepalese cholera strains were found to be nearly identical.
But it's not that simple, says a research group based at the University of Maryland.
  These researchers have found two very different cholera strains in some of the first Haitians to be struck by the disease.