Novel approaches to assess the prevalence of palaeoparasites in European archaeological sites

Palaeoparasitology is the study of parasites, in this case helminths, in archaeological contexts such as well-preserved human remains or sedimentary samples. The robust nature of helminth eggs, along with the distinct life cycle of different species has meant that the study of these organisms have provided insight into aspects such as hygiene and subsistence patterns in archaeological sites. However, discussion and research on the health impact of these parasitic organisms in historical populations is lacking from the published literature despite the significance of these organisms for health today. History is a resource to explore the resilience and spread of helminths, nevertheless, to be useful for informing modern practices the analysis of helminths in archaeological sites needs to be robust, quantified and comparable between sites. There were two methodological changes to palaeoparasitology which were investigated in this thesis to address this problem. The first was to produce a proxy for the prevalence rates of helminths in past societies. Most published studies are either undertaken on communal samples, where it is difficult to associate the quantity of helminth to the number of human hosts, or small scale studies of individual burials within a site. In this thesis, a large scale analysis of helminths from single burials in a number of archaeological sites was undertaken, and concordance between prevalence and risk factors in past and present populations was identified. These results were used to explore the effectiveness of different interventions utilised by modern health practitioners. Currently most studies utilise ancient DNA analysis in palaeoparasitology to confirm species identification so, the second goal was to develop genetic methods to produce data that could be used to study population dynamics and dispersal of helminths. This thesis explores the strength and weaknesses of different genetic approaches to palaeoparasitology, which provide a valuable foundation for future studies to identify the most appropriate techniques for their research questions. This thesis shows methods for making robust conclusions on the incidence and factors that control the spread of helminths in historical populations. This is vital if the work is to be of use for informing modern practices