In the 14th century, a pandemic swept the world.

The Black Death originated in Asia and spread to the Mediterranean, killing millions of people across continents. Italy was one of the first countries to be devastated. Sailors who arrived in the port of Venice were separated from society for 40 days, in perhaps the earliest known form of quarantine.

“It’s eerie, the familiarity,” says historian Frank Snowden, as a disease from Asia once again creeps across the world — wreaking particular havoc on Italy.

Of course, the coronavirus that emerged in Wuhan, China, is far less deadly than the bubonic plague, which wiped out ⅓ of the Earth’s population. Early estimates put the fatality rate of COVID-19 at 3.4%, possibly much lower.

But Snowden, author of “Epidemics and Society: From the Black Death to the Present” and professor emeritus of history and history of medicine at Yale University, says a disease’s fatality rate doesn’t necessarily equate to its importance in society.

And deadly diseases can change history. From the Black Death to the HIV/AIDS epidemic, the effects of which are still felt today, pandemics and epidemics shape the societies in which they are incubated and spread.

Interview Highlights

On the impact of the Black Death

“It had a devastating impact on every aspect of society: the arts, religion, the economy. It promoted the power of the modern state because communities had to organize to prevent this disease, and that took an enormous centralizing authority, which even needed an army, administrative personnel. It needed civil authorities, boards of health. This took enormous resources. And therefore, it's not by chance that the plague centuries are marked by the emerging power of the modern state. And the plague, in fact, is one of the factors that helps that process along.”

On how the first quarantine developed from the Black Death

“That's right. Absolutely. Venice devised a protective device to ward off arrival from the east by using quarantine. That is, they decided to put all ships that were landing ... into a fortress-like place, where the crews and their cargoes and passengers were kept for 40 days, on the idea that after that, they would be safe. They didn't understand what the incubation for plague would be. They guessed 40 days for religious purposes. And that turned out to be more than the incubation period. And so, in fact, it did protect Venice. And Venice ceased to be ravaged by the end of the 17th century. So these were measures that had effective means of protection against the bubonic plague. And we're indebted for the ideas of contagion and quarantine, isolation and social distancing that we see playing out in front of our eyes today.”

On the results of the Spanish flu in the 20th century, which spilled over from birds to humans and killed some 50 million people globally

“Of course, it's a misnomer. It had nothing to do with Spain. It's just that Spain was neutral in World War I, and so its press was not censored. So Spain was the place where the news got out of exactly how bad it was. … Interestingly, though its mortality was huge, its impact was not the same as the Black Death. And indeed, it's often known as the forgotten pandemic. In fact, we just had the American president talk about, ‘Oh, influenza, it's like influenza, coronavirus, and influenza is nothing,’ he said, that kind of thing. So this is, I think, gives us an idea of how it's not simply the body count that tells us how important a disease really is. And there are other diseases, like cholera, that had a limited body count, but a huge impact on civilization.”

On comparisons between the coronavirus and the swine flu of 2009

“It would be a very brave person to make a prediction of what the end result of the coronavirus is going to be. … We don't know, and it's still to be played out, how effectively public health officials and countries will be in developing measures to contain and mitigate the disaster. So I don't want to take the pessimistic line of sounding the alarm and say, yes, this is going to be swine flu or it's going to maybe even be worse. I just want to say we don't know yet, but it clearly has the possibility of something really dreadful. And one can easily, all too easily, imagine this being worse than swine flu.”

On how being hard to detect makes a disease harder to contain, such as in the HIV/AIDS epidemic, which has killed more than 30 million people globally

“This is one of the huge factors that's really important. That is to say, modern public health depends on monitoring the population, knowing who's being affected and then being able to move to isolate those people, identify their contacts, quarantine them. And those measures become very, very difficult if you don't have an easy and rapid diagnostic test. And coronavirus, happily, no one is sick for as long as people are contagious with HIV/AIDS. But nonetheless, that factor is really a major one that's propelling this disease forward ... It's been transmitting silently now for some weeks and no one knew that it was actually already there. So this is a very dangerous part of the coronavirus.”

On his one piece of advice to the United States to handle the coronavirus

“I think the first thing that makes all of the other measures possible is accepting reality. This is something that is real and important, and we can do something about it if we accept the science of it and mobilize and share our resources and not think that we can block it by false measures like bans and national barriers and all the rest of it. Because coronavirus does not respect national borders or wealth or any of those things that we like to tell ourselves are bulwarks of protection.”

Francesca Paris produced and edited this interview for broadcast with Todd Mundt. Paris also adapted it for the web.