Nutritional Factors in the Paleoepidemiology of Infectious Disease in the Ancient Atacama Desert

The adoption of agriculture in ancient human groups is thought to have resulted in a general decline in health, as evidenced by an increase in skeletal markers of infectious disease and nutritional stress in post-transitional populations. It is possible that the reduction in dietary diversity and associated increase of micronutritional deficiencies that accompanied agriculture intensification and dependence on staple-crops contributed to an increased prevalence of infectious disease in the past. Clinical research has provided evidence for integral roles of various micronutrients in a number of immune mechanisms, and epidemiological data has demonstrated a relationship between poor micronutritional status and an increased incidence of bacterial infectious diseases. The Atacama Desert is a marginal, hyper-arid environment which has been continuously occupied for approximately 13,000 years. Beginning around 2500 BP, the people of this region began transitioning from a maritime-based hunter-gatherer subsistence strategy to a horticulturalist economy. Although the bioarchaeological record of this region is well studied, the impact of subsistence change on human health in the northern Chilean Atacama represents a new avenue of investigation. This thesis explored the potential relationship between micronutritional deficiencies and infectious disease across the agricultural transition in the ancient Atacama Desert of Northern Chile to test the widely held paradigm of the adoption of agriculture as an epidemiological transition. Palaeopathological analysis was conducted on two cohorts comprising nine archaeological sites from the Arica Region of Northern Chile (N = 187). The pre-agricultural cohort consisted of 72 individuals from the Archaic Period sites of Morro 1 and Morro 1-6, while the horticulturalist Formative Period cohort consisted of 115 individuals from the sites of Azapa 14, 70, 71, 75D, 75E, and 115. All individuals were examined for skeletal evidence of vitamin C deficiency (scurvy), mineralisation disorders (vitamin D and/or calcium deficiency), anemia, treponematosis, and tuberculosis. It was hypothesised that the prevalence of all of these conditions would be significantly higher in the Formative Period group and that an association would be found between skeletal evidence of micronutritional deficiencies (i.e. scurvy, mineralization disorders, and anemia) and infectious disease (treponematosis and tuberculosis). No evidence of tuberculosis was recovered in either group, however there was a significant decrease in evidence of treponematosis between the Archaic and Formative Periods. Scurvy was the only condition which increased significantly across the transitional period. No significant association between skeletal evidence of micronutritional deficiencies and treponematosis was found. This thesis was unable to provide support for the adoption of agriculture as an epidemiological transition in the ancient Atacama Desert, and it is argued that a convergence of evolving social practices, including the abandonment of complex mortuary ritual, and an increase in the frequency of ENSO events contributed to the increase in scurvy and decrease in treponematosis in the Formative Period