Justinian Plague reassessed: Black rat studies

[guy]

 

There have been several posts before about possible bubonic plague in Ancient Rome. (See posts below.)

Rufus of Ephesus (70-110 AD) had mentioned earlier plagues that were possibly a form of bubonic plague. These earlier plagues described by Rufus were much less virulent than the later suspected Bubonic Plague of Justinian (541-549 AD) and Black Death that devastated Europe (1347-1352). These plagues of Rufus may have even been some other disease entirely. 

It is thought by many that black rats and fleas were important in the spread of the bacterium (Yersinia pestis) that caused bubonic plagues. Finding evidence of ancient black rat populations would support the presence of ancient bubonic plague, at least during the reign of the Eastern Emperor Justinian.

This study shows that black rat population both waxed and waned, most notably during and after the Justinian Plague.  

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The study -- led by the University of York along with the University of Oxford and the Max Planck Institute -- is the first ancient genetic study of the species (Rattus rattus), often known as the ship rat.

By analysing DNA from ancient black rat remains found at archaeological sites spanning the 1st to the 17th centuries in Europe and North Africa, the researchers have pieced together a new understanding of how rat populations dispersed following the ebbs and flows of human trade, urbanism, and empires.

The study shows that the black rat colonised Europe at least twice, once with the Roman expansion and then again in the Medieval period -- matching up with archaeological evidence for a decline or even disappearance of rats after the fall of the Roman Empire.

The authors of the study say this was likely related to the break-up of the Roman economic system, though climatic change and the 6th Century Justinianic Plague may have played a role too. When towns and long-range trade re-emerged in the Medieval period, so too did a new wave of black rats.

 

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Black rat remains are found throughout the Roman Empire in the 1st–5th centuries CE, but rarely beyond its northern borders, suggesting that these rats were dependent on a Roman economic system characterised by a network of dense settlements connected by bulk transport via efficient road, river, and maritime route.

With the breakdown of the Roman Empire from the 5th century onwards, evidence for the existence of black rats becomes scarcer. They may have been extirpated entirely from the northern provinces including Britain, and the percentage of archaeological sites with black rat remains declined even in the Western Empire’s Italian core. By contrast, black rats remained common in the Balkans and Anatolia until at least the 6th century CE, presumably reflecting continued stability in the Eastern Roman Empire. [This would coincide with the Justinian Plague (541-549 AD.]

A decline in the European black rat population during the 6th–9th centuries has previously been suggested based on zooarchaeological evidence. This has been attributed to several causes including: (a) the demise of the Western Roman Empire’s economic and urban system from the 5th century CE, including the cessation of large-scale grain shipments that may have helped to disperse and support rat populations; (b) climatic cooling in the ‘Late Antique Little Ice Age’; and/or (c) the Justinianic Plague, which began in 541 CE and is likely to have infected rat populations previously naive to Yersinia pestis, regardless of their potential role in its spread among humans. Our finding of a post-6th-century turnover corroborates this apparent decline, though the density of our samples’ spatiotemporal coverage is not sufficient for us to distinguish between the potential causes. 

 

This study supports the belief that at least the Justinian Plague (among all of the ancient plagues) was a form of the bubonic plague.
 

The plagues were able to quickly spread thru developed societies that facilitated trade (and disease) from more distant locations. Grain transport, for example, would bring both needed food supplies and infected rats over a long distance. The plague would diminish either because these trade networks became disrupted or (less likely) climate change impacted on the rat populations.

 

https://www.nature.com/articles/s41467-022-30009-z

 

https://www.sciencedaily.com/releases/2022/05/220503141339.htm

 

 

Edited May 4, 2022 by guy