Lazzaretto Vecchio is an island in the Venetian lagoon located near the Lido, the 12 kilometer long bar located to the east of the city, bordering the Adriatic Sea. 600 years ago, Lazzaretto was the place chosen to locate the first confinement hospital in the world.
In the middle of the 14th century, specifically between 1346 and 1347, the largest epidemic of the Black Death in the history of Europe broke out, comparable only to the one that devastated the continent in the time of Emperor Justinian (482-565AD). Shortly after, as a preventive measure against contagious diseases, the Venetians devised in 1423 an isolation space that has gone down in history as lazarettos.
Researchers at the University of South Florida (USF) have had access to remains of people who died from the Black Death to extract DNA from the teeth of up to 900 skeletons excavated at Lazzaretto Vecchio. Their objective was to determine whether quarantines were really effective against pandemics.
Andrea Vianello, visiting researcher at USF and a native of Venice, has been coordinating the project to develop the site's first genetic database, allowing evolution to be traced over 300 years to determine if the introduction of containment measures, such as masks and confinement, had an impact.
“The Venetians invented isolation and masks to deal with pandemics and it seems they worked,” Vianello said in a statement. "Our project will scientifically prove its effectiveness, before vaccines and medicines existed. We will see if the quarantine island stopped any epidemics," he adds.
Professor of anthropology Robert Tykot, for his part, explained that this "is the first time" that there is "a set of genetic sequences of pathogens present in a single place and, in parallel, see the changes in local populations". "We have thus been able to study the coevolution of pathogens and humans, unhindered by the rapid mutations of modern viruses or the presence of vaccinated people," he adds.
The team of researchers began the historical plague project earlier this year by tracking the effects of the Justinian-era pandemic, known as the world's first plague. Experts studied a mass burial site in Hueras (Jordan).
Geneticist Rays Jiang, an associate professor in the School of Public Health, helped identify the plague bacterium in Jordan and is excited to expand his research with the study of Lazzaretto Vecchio, a World Heritage site he has described as a time capsule and treasure trove for genetics.
"This unique quarantine island may contain devastating plague pathogens, the syphilis pathogen and the anthrax pathogen that jumped from animals," Jiang said. "For the first time, we will be able to capture multiple pathogens that have coexisted in human populations for three centuries," she notes.
"Studying past pandemics is useful for preventing future ones, as it allows us to identify epidemic patterns, track pathogen evolution, understand cultural and social contexts, learn from mistakes, anticipate challenges, and inform public health policy," Jiang concludes.
