Abstract
Throughout the centuries, the undefended nature of man has very often manifested in cases of epidemics, which have determined scenarios of suffering and death. Through “historical” observation lens, it is possible to understand the relationship between the spread of viruses, bacteria and parasites responsible for these epidemics and the displacement of ancient or contemporary travellers. We have analysed two infective diseases, syphilis and SARS, and their role in history and in medicine.