I'm not sure of that angle, but it wouldn't suprise me in the least. Perhaps the Europeans had more resistance than the Indian's, who were unable to fight even basic european diseases that people had built up a resistance to over the centuries. IOW, something that would sicken a european for a week or two would kill them in days.
Syphillis shows up in Europe shortly after 1492. The dominant hypothesis is that Columbus and his colleagues brought it back from the New World.