Implications of human interaction for health of past populations in Asia

Abstract

Drivers of human mobility such as migration, trade and conflict is today recognised to considerably influence the spread and prevalence of infectious diseases globally. Additionally, these factors are known to impact nutritional levels of migrating populations. However, the impacts of interactions between two or more populations, which occurs following human mobility, has received little attention in the palaeopathological literature. This thesis investigates whether human population interaction significantly influenced the health of prehistoric populations in Asia. Six skeletal assemblages across three case studies (n=450) in Asia’s prehistory were explored to assess the level of nutritional and infectious diseases. These were the Middle to Late and Final Jomon (5000-2300BP), Pre-Neolithic to Neolithic Vietnam (6900-3500BP) and Bronze Age to Xiongnu Period Mongolia (4500 to 1800BP).

The questions proposed for this thesis were: 1) Did increasing levels of population interaction over time significantly affect the health of populations in prehistoric Asia? And; 2) How did population interaction interplay with a range of other sociocultural, biological and ecological factors to influence the health of populations in prehistoric Asia?

It was hypothesised that human interaction would have a considerable impact on the health of prehistoric populations from Asia, but that other sociocultural, environmental and biological factors would mediate the degree of impact. To assess the implications of human population interaction on prehistoric health, protocols of weighted diagnostic criteria for differential diagnosis of infectious diseases, nutritional diseases and anaemias in dry bone were developed to standardise identification where they do not yet exist in the palaeopathological literature. Additionally, inclusion criteria for an overall infectious disease prevalence, that encompasses specific and non-specific infectious diseases, was developed. A three-stage statistical approach was applied to address the research questions. This involved analysis within assemblages (site level), diachronically across two assemblages in the same region (regional level) and across all assemblages to assess general trends in the influence of human population interaction on disease dynamics (continent level). The results of this study demonstrated that varying levels of human population interaction influenced the prevalences and diversity of infectious diseases in Asia, but only indirectly influenced the prevalences of nutritional diseases. However, residential mobility and population density served to mediate the impact that human population interaction had on infectious disease prevalences and diversity in past populations. Therefore, the hypothesis was supported for infectious diseases but not nutritional diseases. Additionally, the impact of disease on mortality was variable and dependent on the pathogens introduced through human population interaction processes.