In late 2008, the Tricell Pharmaceutical Company began operations in the region, slowly releasing multiple genetically-enhanced forms of Las Plagas throughout the area. By early 2009, the increasing xenophobia and active racism against non-natives spread the plagas quickly through those willing to spread it and those forced to be impregnated with it.
The military was sent in to stop any further spread by having a large wall built around the destabilized zone, cutting through a large portion of the region.
The B.S.A.A., under command of Chris Redfield, was sent in originally to stop the supposed smuggling of materials by TriCell employee Ricardo Irving, only to be faced with the threat of the plaga-infected Majini and the mysterious Uroboros project.