Contact tracing is one of the techniques that is now being used to help manage the coronavirus pandemic. Today, 21st century systems of telecommunications and surveillance have led the way in identifying those who have been in contact with the infected, but the concept has its roots in Italy, dating back to a doctor in 1500s.
While treating patients on the shores of Lake Garda at Desenzano in northern Italy during the bubonic plague outbreak of 1576, physician Andrea Gratiolo used contact tracing in a manner we can recognize today. It was employed not to trace the spread of plague, but to disprove that it derived from a woman who was rumored to have carried it to the town after traveling from Trento, where she lived.
The doctor noted that the woman had “taken a small and tightly packed boat with 18 others…sleeping on top one another.” One woman had slept all night with her head in the accused woman’s lap. Gratiolo also investigated the household of the second woman and discovered that “she, her husband and their four small children all slept in the same bed.”
In a plague treatise published later that year, Gratiolo argued that the boat’s passengers and the entire household of the accused should have become infected, yet none had. In further evidence of contact tracing, he adds: “no other person that the accused had associated or interacted with had caught the disease.”
Dr. Gratiolo used the bulk of his treatise to dispel popular theories of the plague’s origin. These ranged from concepts that disease was derived from air that was “thick, swampy, foggy and stunk;” that it came from bad food that corrupted the humors and even that it originated celestially, due to certain configurations of the stars. The doctor’s ideas did not spring from an ideological vacuum. During the plague outbreak of 1574-78, other medicos were also questioning the prevailing theories of the day. Gratiolo questioned the first principle of plague causation that existed from the time of the first plague outbreak centuries earlier – that is was a punishment from God. To curb the spread of diseases, Gratiolo believed that doctors should focus on natural causes and leave questions of God to the theologians. Gratiolo’s plague investigation was an enlightened approach and is a fine example of how stories and rumors can spread as quickly as the disease itself. It is yet another lesson that we can learn from history. Unfortunately, it is also a message that gets lost in our age of 24-hour news services.