Paleodemographical Analyses of Plague Outbreaks in Italy Before and After the Black Death of 1347-48
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Paleodemographical analyses of plague outbreaks in Italy before and after the Black Death of 1347-48. Irene Barbiera, Researcher, University of Padova, [email protected], ORCID: orcid.org/0000-0002-3251-5960 ; tel work: 0039 049 827 4113; mobile: 0039 3498109814 Maria Castiglioni, Associate Professor, University of Padova, [email protected], ORCID: orcid.org/0000-0003-3977-8517 Gianpiero Dalla Zuanna, Full Professor, University of Padova, [email protected], ORCID: orcid.org/0000-0001-7011-4028 Keywords: paleodemography, medieval population, Black Death, d index. Abstract In this study we show how the paleodemographic analyses of skeletal data – found in Italian cemeteries dated before, concurrently and after the Black Death – can offer useful insights to understand population dynamics of the past, with a special focus on the centuries affected by strong and recurrent epidemic outbreaks. Our research on the one hand contributes to recent debates around the pandemics that afflicted Europe dating from the Early Middle Ages and on the other it offers an interdisciplinary contribution to the study of mortality crises, auspicated by the same scholars involved in these debates. The aim of this research is manifold. First of all we developed a reliable method to trace mortality trends both in periods of normal mortality and in periods affected by mortality crisis. Secondly, applying such method we contribute to the ongoing debates concerning the impact of Y-pestis in Italian medieval population. We show that both the First (Justinian Plague, 6th-8th centuries) and the Second (Black Death, 14th-15th centuries) Pandemics restrained the growth of the Italian population, with consequent changes in the population pyramid and demographic equilibrium. However the spread and lethality of the Black Death have been more intense than those caused by the Justinian Plague. 1 Before discussing our methods and outcomes, we will consider in some detail the most recent debates concerning the outbreaks which have affected Italy and Europe for three centuries, from 1348. 1. DEBATES AROUND THE BLACK DEATH «I say, then, that the sum of thirteen hundred and forty-eight years had elapsed since the fruitful Incarnation of the Son of God, when the noble city of Florence, which for its great beauty excels all others in Italy, was visited by the deadly pestilence. Some say that it descended upon the human race through the influence of the heavenly bodies, others that it was a punishment signifying God’s righteous anger at our iniquitous way of life. But whatever its cause, it had originated some years earlier in the East, where it had claimed countless lives before it unhappily spread westwards, growing in strength as it swept relentlessly on from one place to the next (Translated by G.H. McWilliams 1995). With these words Giovanni Boccaccio witnessed the arrival of the Black Death in Italy in the famous introduction to the Decameron. The contagion was at first brought to Messina (Sicily) by a Genovese jailer arriving from Crimea in September of 1347. From there it spread throughout Sicily, reaching the port of Marseille in November and from 1348 it spread to Western Europe, reaching Great Britain probably in April of that same year. This disease of rodents, which particularly affects rats, can be transmitted to humans by a vector: the flea. When a flea sucks blood from an infected rodent, some of the bacteria settle in the flea’s proventricolus where they multiply, preventing the flea from getting proper nourishment. The flea does not get infected, rather it becomes a healthy carrier. When the rat dies, the hungry flea can bite humans, regurgitating the plague- carrying bacteria into their tissue, from where the infection reaches the lymphatic system, producing the buboes in 2 correspondence of lymph glands (Audoin-Rouzeau 2003; Gratz 1999; Tikhomirov 1999; Del Panta 1980). In concomitance with the appearance of buboes, other symptoms of Yersina pestis infection are high fever, headache, malaise, shaking chills, inflammation of interior organs. For some reasons still unclear, plague can cause a blood infection, generating a septicemia form which is inevitably lethal and kills within 24 hours. In other cases, in the same way unclear, plague can generate an infectious pneumonia, provoking a secondary pneumonic form of plague, which kills within three days, having a lethality tax of 99%. In this case the disease can be transmitted person-to-person, through saliva, coughing and sneezing provoking a primary pneumonic plague which is also transmissible person-to – person (Poland and Dennis 1999; Gani and Leach 2004; Alfani 2010). If scholars now agree that the plague represented the most devastating epidemic ever to hit Europe in Medieval and Early Modern times, still many doubts remain about the forms it took, the timing of its transmission, the symptoms and the mortality levels it provoked. More recently the topic of plague has once again become of prime interest, becoming the object of a vivid debate between those who began doubting that the Black Death was provoked by the bacillus of Yersina Pestis, identify by Alexander Yersin during the plague which spread in Hong Kong in 1894,1 and those who still maintain the strong connection between Yersina Pestis and Black Death. A fundamental contribution to these debates has recently been offered by genetic analyses aimed at identifying the DNA of Yersina pestis in medieval skeletons and at tracing its evolution through time. In a first study, carried on in 1998, scholars extracted DNA from the dental pulp of a number of individuals who had died of plague and who were buried in common pits connected to two hospitals in Labesc and Marseille. These were used as places of quarantine 1 It would have been anthrax according to TWIGG (1984), viral hemorrhagic fever similar to Ebola according to DUNCAN, SCOTT (2004). According to a more conciliatory hypothesis advanced by THEILMANN, CATE (2007), Yersina Pestis would have occurred in concomitance with other virulent diseases. 3 for people affected by the Plague in 1590 and in 1772. According to the authors of this study, fragments of genome belonging to Yersina pestis could be identify in the pulp of the investigated teeth (Drancourt et al. 1998). Subsequent analyses, performed on diverse samples from Northern European sites did not succeed in identifying the genome of plague bacillus. Doubts were thus raised about the validity of the first study (Gilbert et al. 2007). More recently, new sequencing techniques allowed traces of Yersina Pestis DNA to be identified once more in some skeletal samples excavated in different sites in Europe: Hereford (UK), Bergen op Zoom (The Netherlands), Augsburg (Germany), Parma (Italy), Saint-Laurent-de la Cabresse (Spain) (Haensch et al. 2010) and Smithfield in London- the well known cemetery used during the Black Death epidemic between 1348 and 1349 (Bos et al. 2011). These new analyses highlighted new pathogens related to Yersina Pestis, suggesting that the Ninth-century Bubonic plague was derived from the Fourteenth-century plague, which had changed over time (Geddes de Filicaia and Geddes de Filicaia 2015; Green 2014). Similarly, the Justinianic Plague also turned out to be provoked by a bacillus related to the biovars involved in subsequent pandemics (Wiechmann and Grupe 2005; Cui et al. 2013; Wagner et al. 2014). Given such relations, scholars now agree that the of Justiniaic Plague (541 B.C.) can be defined as First Pandemic, The Black Death as Second Pandemic and the 19th century Bubonic Plague, as Third Pandemic (Green, 2014). Despite the fact that many doubts about the etiology of the plague are now being resolved, there are still several unclear points concerning the lethality and the modes of its transmittance in the Middle Ages. The mechanism of plague transmission: from rat to flea and from flea to humans, detected for the Third Pandemic does not seem compatible with the speed of transmission of the Second Pandemic. First of all, the flea which transmits the plague bacillus, Xenophilla cheopis, prefers rats to humans, therefore it will most probably attack humans only after the 4 population of rats dies out. Moreover, the transfer from rats to humans requires a quite close cohabitation among the two. Written sources of the medieval period describing the plague do not mention rats nor any blight of rodents. Contrary to these observations some scholars emphasize that the lack of rats from medieval sources might simply be due to the fact that at that time people were unaware of the mechanism of transmission and of role of rats in carrying the plague (Theilmann and Cate 2007). These scholars hypothesize that the disease probably assumed the bubonic and pneumonic forms simultaneously, thus, triggering direct transmission person-to-person (Theilmann and Cate 2007; Del Panta 2007). Also the modalities of micro-diffusion of the Nonantala plague in the epidemic of 1630 seem difficult to interpret without hypothesizing a person-to-person transmission of the disease (Alfani and Bonetti in press). On the other hand, pneumonia plague occurs only after the diffusion of the bubonic form and under very particular climatic and environmental conditions; it is not certain that these circumstances occurred in the Middle Ages (Alfani 2015). In addition, bubonic plague, as transmitted by the flea, spreads in hot or mild temperatures, i.e. between summer and early autumn, while pneumonia spreads predominantly in winter. In this regard, an analysis of the occurrences of testamentary acts in the cities of Bologna, Orvieto, Siena, Arezzo, Florence and Perugia in 1348, carried out by Cohn, shows that these became particularly numerous between June and September with considerably high peaks in July, indicating a greater incidence of deaths at this time of year (Cohn 2002). Also in Bologna there is a peak of testamentary acts dating from June and July of 1348.