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Black Death: how can we learn from the spread of disease along the Silk Roads?

31/03/2020
03 - Good Health & Well Being
11 - Sustainable Cities and Communities
16 - Peace, Justice and Strong Institutions

This article explores the spread of plague, known as ‘the Black Death’, across the Silk Roads of the 14th Century CE. It examines ways in which people responded to the disease and looks at how we can respond to newly arising challenges today, utilizing the Silk Roads as an instructive example of the benefits of an interconnected world built on collaboration and timely and reliable knowledge sharing.

The example of the Black Death can be inspiring for dealing with challenges caused by the outbreak of epidemics in our contemporary world. Unlike in the 14th century, today we can identify new viruses, sequence their genome, and develop reliable tests for diseases in just a few weeks. It may be tempting in uncertain times, particularly now as the world is witnessing the rapid spread of COVID-19, to conclude that the only way to prevent challenges such as the spread of infectious diseases is to restrict movement and exchange, and somehow roll back globalization and the connectedness of different cultures and peoples. However, the spread of plague in a world without planes, trains and cruise ships, serves as a reminder that diseases can move rapidly even without such technologies.

Although we live in an age of intense globalization that seems unprecedented, human movement, exchange and interconnectedness are not recent phenomena. In fact, people have always moved from place to place and exchanged goods, skills and ideas across vast distances. The outbreak of the Black Death and its spread along the Silk Roads would be a timely reminder that one of the greatest defences against newly emerging challenges is the exchange and collective analysis of reliable knowledge and experience. Despite the tremendous speed of the circulation of people and goods around the world today, humans are ready to face the challenges that may result from these interactions, largely thanks to collaborations and collective experiences and these will continue to play an important role in tackling and preventing the spread of diseases.

The Silk Roads are an instructive reminder that human beings do not occupy isolated worlds but a shared and interdependent one that flourishes when they interact with one another. Interactions across vast distances, such as those which took place along these historic routes, have made an undeniable contribution to the enrichment of life and culture. Now, as in the past, increasing human interconnectedness and movement presents challenges but also opportunities in numerous fields including science, medicine and epidemiology, and greatly adds to the improvement and richness of our daily lives. The constant movement and mixing of populations along the Silk Roads had a profound impact on the history and civilizations of the peoples of Eurasia and indeed of people worldwide, driving the development of knowledge, ideas, beliefs, culture and identities. Science, arts and literature, as well as knowhow, crafts and technologies were shared and disseminated into societies along the lengths of these routes.

However, wherever people, animals, and goods have moved and brought enriching effects, undesirable phenomena such as disease have also been transmitted on a broad scale. Just as global movement and connectedness is not a new phenomenon, neither is the potential for, and the occurrence of, epidemics. Among the different kinds of parasites, bacteria and viruses, and their associated diseases, that were transmitted along the Silk Roads, plague was one of the most notable. Plague is a disease caused by the bacteria Yersinia pestis, commonly carried by fleas.

Three pandemics of plague have occurred in human history: the best-known and perhaps largest was the second outbreak often referred to as the “Black Death”, which infected vast numbers of people across Eurasia, and killed somewhere between 75 and 200 million. The outbreak peaked between 1347 and 1351 CE, reaching the trade ports of Europe by 1346. A number of theories exist as to where the 14th century plague originated and how exactly it spread. One of the most often cited is that it was carried by infected rodents across the Silk Roads, reaching Europe along with infected merchants and travellers.

Societies were very limited in their ability to treat and prevent the spread of plague in the 14th century as there was no accurate knowledge available about the exact cause of the disease or of effective treatments. Indeed, fleeing remained one of the only effective preventative public health measures available to people at the time. Whilst the attempted cures for plague had very little effect, the Black Death did prompt Europe and other parts of the world to expand and refine public health measures, particularly in the subsequent decades and centuries as the disease continued to periodically return. Furthermore, some methods for preventing the spread of plague, such as making suspected vessels and travellers remain in isolation for 40 days before they were allowed to enter the city of Venice, are still practiced today, and it is from this practice that we derive the term “quarantine”.

The transmission of the Black Death, and the damage that it caused to societies in Asia and Europe, are undoubtedly examples of a disastrous catastrophe that trade, and interactions, helped exacerbate. However, an overall assessment of the outcomes of the exchanges along the Silk Roads reveals that despite some negative effects, these interactions have brought vast benefits and enriched human life and culture. In fact, the medical sciences have been one of the direct beneficiaries of these intercultural exchanges. During the medieval or “post-classical era” (500-1450 CE), scholars made large contributions to the fields of medicine, pharmacology and veterinary science thanks to the circulation of knowledge and ideas. The movement of people and knowledge across the Silk Roads facilitated the widespread translation of work from other parts of the world into Arabic, making a broad array of scholarship accessible to polymaths of the day. Their work synthesised and built on existing medical knowledge, such as that developed in Ancient Greece and Rome, and combined this with knowledge from other regions of the world such as China and the Indian subcontinent.