The archaeology of epizootic disease: identification and diagnosis of ovine mass mortalities in archaeological deposits
Friday seminar by Annelise Binois
Epizootic disease and other animal mass mortalities have undoubtedly been a major concern for agro-pastoral societies ever since mankind started to rely on domestic animals for subsistence, and there is ample historical evidence testifying to this fact. Archaeological evidence for such events is however almost completely lacking: hardly any sites or deposits relating to an epizootic outbreak have ever been identified or studied, and no diagnosis has to our knowledge ever been attempted.
Our research aims to address this knowledge gap by developing an interpretative framework for the understanding of archaeological animal carcass accumulations. Two questions spring to mind when faced with such a deposit: that of the origin of the deposit, ritual or mundane, and that of the cause of death involved. Using contemporary veterinary science, historical sources and bio-archaeological data, we elaborate criteria for demonstrating whether an animal carcass deposit is, or not, to be interpreted as the consequence of a mass mortality, and in the event that it is, for identifying probable diagnostic hypotheses.
Since most mortality events leave no traces on the bones of their victims, we have developed a paleo-epidemiological diagnostic approach based on indirect evidence. By a reasoned analysis of judiciously chosen historical sources, we list the most frequent causes for mass mortalities in pre-modern sheep flocks, and we establish an epidemiological profile for each of these causes, compiling its characteristics in terms of age, sex, season, terrain, etc. The same information is obtained for the archaeological assemblages by classical bio-archaeological analysis, and the profiles acquired by both methods are then compared. Statistically probable diagnostic hypotheses can therefore be identified, and be subsequently verified by further analysis, especially, when appropriate, by the identification of paleopathogens.
This presentation exposes our approach and applies it to the example of the sheep deposit from Achères (France), a 17th - 18th century pit containing the complete bodies of 18 adult and sub-adult sheep. We show that the animals quite certainly died in a mass mortality event, and suggest two possible causes of death, anthrax and grain poisoning.
DVM, PhD student, Environmental Archaeology Section, CNRS UMR 7041 ArScAn, Nanterre, France / University of Paris 1 Panthéon-Sorbonne, Paris, France