No plague in the land? Infections diseases and their implications for the pre Columbian-transoceanic-contacts controversy

Prof. Stephen C. Jett

The supposed epidemiological „virgin-soil“ character of the 1492 New World with respect to most serious Old World infectious diseases has caused many to reject the possibility of significant pre-Columbian contacts by sea between the hemispheres. However, most Old World diseases‘ putative absence in the Americas may be a result of: 1) a lack of those diseases in contact source areas at the times involved; 2) sailor’s immunity to acute infections owing to childhood exposure; 3) on-board elimination of any such infection, owing to voyage lengths‘ exceeding lengths of incubation times plus contagiouseness time; and 4) lack of concentrated American populations large enough to support endemism, so that any introduced acute infections would soon have died out. Thus, the seeming pre-Columbian non-presence in the New World of most Old World communicable diseases does not demonstrate that important pre-1492 contacts did not occur. Contagious diseases that apparently were shared between the hemispheres included syphilis, tuberculosis, and typhus. Although not a present demostrable, there is some reason to suppose that one or more of these shared maladies may have been transferred across the oceans well before 1492. Key words: disease, epidemiology, transoceanic contacts, Americas.