Differential word expression analyses highlight plague dynamics during the second pandemic.

Rémi Barbieri,Michel Drancourt,Riccardo Nodari,Sara Epis,Didier Raoult,Michel Signoli

doi:10.1098/rsos.210039

Abstract

Research on the second plague pandemic that swept over Europe from the fourteenth to nineteenth centuries mainly relies on the exegesis of contemporary texts and is prone to interpretive bias. By leveraging certain bioinformatic tools routinely used in biology, we developed a quantitative lexicography of 32 texts describing two major plague outbreaks, using contemporary plague-unrelated texts as negative controls. Nested, network and category analyses of a 207-word pan-lexicome, comprising overrepresented terms in plague-related texts, indicated that ‘buboes' and ‘carbuncles' are words that were significantly associated with the plague and signalled an ectoparasite-borne plague. Moreover, plague-related words were associated with the terms ‘merchandise’, ‘movable’, ‘tatters', ‘bed’ and ‘clothes'. Analysing ancient texts using the method reported in this paper can certify plague-related historical records and indicate the particularities of each plague outbreak, which can inform on the potential sources for the causative Yersinia pestis.

Highlights

Plague, a deadly zoonosis caused by the bacterium Yersinia pestis [1,2], has been incontrovertibly identified via palaeomicrobiological research on numerous historically described burial sites in Europe, ending decades-long controversies regarding the aetiology of the so-called ‘Black Death’ (1346–1353)royalsocietypublishing.org/journal/rsos R
Our data, coupled with existing palaeomicrobiological analyses [3,4,8,26,28], confirm that these ancient texts describe a plague caused by Y. pestis, as revealed by the significant presence of the words ‘buboes’ and ‘carbuncles’, which were the two main symptoms of the 10 plague during the second pandemic
One contribution of our analysis is that it expands the scope of possibilities concerning the sources and routes of contamination during two plague outbreaks

Summary

Introduction

A deadly zoonosis caused by the bacterium Yersinia pestis [1,2], has been incontrovertibly identified via palaeomicrobiological research on numerous historically described burial sites in Europe, ending decades-long controversies regarding the aetiology of the so-called ‘Black Death’ (1346–1353)royalsocietypublishing.org/journal/rsos R. The related episodes that formed the second plague pandemic, which lasted from 1346 until the 2 nineteenth century [3,4,5,6,7,8,9]. An extensive analysis of the differences between the second and third plague pandemic historical descriptions demonstrated that the two pandemics exhibited such different epidemiological and clinical descriptions that they may even have to be considered two different diseases [21]. The sources of plague during the second pandemic could be related to clothes and goods, with no reference to epizootic episodes among rats [21]. The incidence of infection was higher for individuals living in the same household, suggesting that the plague was able to spread from humans to humans [22,23,24]

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Conclusion