It is exactly one of the starting points of this uchrony, Civilizations from Laurent Binet (in french, i believe not translated to english), where native get sick during first venue of Vikings then when Colombus appears they just don't get sick at all + kill him and get to Portugal back on their boats and then travel in Europe, meet Luther, Erasme & Charles Quint, convert people to Sun god religion and create an Empire in Europe. Good book btw