Tuberculosis
A form of pathology distinctly different from the treponematosis syndrome also affected prehistoric peoples from North and South America (Allison, Mendoza, and Pezzia 1973; Buikstra 1981b).
Expressed most commonly as erosive spinal lesions, less frequently affecting joint surfaces of the limb long bones, this disease is found in North American populations postdating IlOO B.P. The Chilean materials reported by M. Allison and colleagues (1981) predate the North American examples by over a millennium. Pulmonary involvement is reported for three individuals from the Caserones site (c. 1660 B.P.), as well as an isolated case of Potts’s disease dating to c. 2110 B.P.Epidemiological patterning considered with lesion location suggests that the most closely analogous modem disease is tuberculosis rather than blastomycosis, a fungal infection. Both blastomycosis and tuberculosis present similar skeletal lesions, but their expected age-specific mortality patterns differ. Young adults are disproportionately represented among those dying with clinically documented bone tuberculosis, whereas blastomycosis tends to present an age-accumulative profile. The age-specific disease pattern observed in large series, including those from west-central Illinois, resembles tuberculosis more closely than blastomycosis (Buikstra and Cook 1981; Buikstra 1991).
The tuberculosis diagnosis developed from modem clinical literature does not, however, provide a perfect diagnostic fit for our prehistoric example. Through simulation analysis, J. McGrath (1986) has modeled the course of a tuberculosislike disease in Middle Woodland, Late Woodland, and Mississippian populations from west-central Illinois. She concludes that a disease resembling modem tuberculosis would have rendered our prehistoric peoples extinct or would have itself ceased to exist. Thus, either our estimates of group size and interaction frequency are misspecified, or the modem tuberculosis model is not fully transferable to prehistoric contexts. The important role of effective population size in the spread of disease is emphasized in McGrath’s conclusions, underscoring the importance of relatively brief periods of contact involving a large number of individuals. Thus, the role of socially important economic and religious collective activities that encourage population aggregation - however brief - must be considered in explaining patterns of disease spread and maintenance in prehistoric groups.