Endemic treponemal disease in late pre-Columbian prehistory: New parameters, new insights

Pre-Columbian frequencies of bone-disseminated non-venereal treponemal disease (yaws, treponarid) increase with the shift to food production. This increase is associated with two subsistence corollaries: sedentism and settlement aggregation. The later prehistory of East Tennessee includes two socio-politically distinct maize-intensive sedentary agriculturalist phases: Dallas (1300–1550 CE) and Mouse Creek (1400–1600 CE). The Dallas phase is widely distributed across both steep-sided narrow and broad river valleys within the catchment areas of three reservoirs (Tellico, Melton Hill, Chickamauga). The Mouse Creek phase is confined to a single reservoir (Chickamauga) and differs from Dallas in social status/role and settlement organization. Physiographic differences (affecting population density and agricultural productivity) and changes in settlement organization potentially affect treponemal disease prevalence. This study tests these variables in ten sites segregated by phase and geographically by the three reservoirs. Treponemal disease was considered minimally present in a sample based on two levels of diagnostic reliability (i.e., pathognomonic and indicative). Results indicate that physiography does not consistently impact treponemal disease visibility. Negating the role of settlement organization, temporal differences occur only within the Chickamauga Reservoir, suggesting other testable epidemiological influences of extrinsic (e.g., internal Dallas cultural diversity, regionally varying sex roles) and intrinsic (i.e., frailty, disease synergisms) variables.