http://www.nature.com/news/2005/050404/full/050404-12.html
They are also suggesting it came from contaminates vaccine needles reused on the children. :-(
Additional problems were mentioned including lack of reliable electricity, which precluded use of the mobile lab, and burial customs which included washing of the dead body and drinking the water.
What is wrong with these people? It's a freekin' wonder they haven't gone extinct yet!