Skeletal lesions of Treponematosis in Central Chile

SKELETAL LESIONS OF TREPONEMATOSIS IN CENTRAL CHILE María José Herrera-Soto1 & Leandro H. Luna2 1Facultad de Filosofía y Letras. Universidad de Buenos Aires, Argentina. Fundación Mátrida, Chile. Correo: mariajose.herrera@uba.ar 2CONICET, Instituto Multidisciplinario de Historia y Ciencias Humanas (IMHICIHU). Universidad de Buenos Aires, Facultad de Filosofía y Letras y Facultad de Odontología, Cátedra de Endodoncia e Instituto de Investigaciones en Salud Pública (IISAP), Unidad de Investigación en Bioarqueología y Antropología Forense (UIBAF). Correo: lunaranda@gmail.com INTRODUCTION Treponematosis comprise four closely-related infections: pinta –not affects the skeleton-, yaws, endemic syphilis or bejel, and venereal syphilis. These diseases are caused by variants of spirochetal bacteria of the genus Treponema, that may be free-living, commensal, or pathogenic for humans and other mammals (Baker et al., 2020). The treponematosis manifests in three stages: primary, secondary, and tertiary. In all stages, tissue damage is believed to be caused by both localized and systemic inflammation, but distinctive osteological lesions occur only in the tertiary stage (Hackett, 1976; Ortner, 2003). To the America continent, there are various studies that propose the presence of treponematosis in contexts prior to the European invasion (Baker et al., 2020; Betsinger et al., 2017; Filippini et al., 2019). In particular, different subspecies of treponematosis had been proposed to Pre-Hispanic populations that inhabited the Atacama Desert and the Chilean Patagonia (Allison et al., 1982; Aspillaga et al., 2006; Castro et al., 2020; Standen et al., 1984; Standen and Arriaza, 2000). Here, we evaluate the presence of osteological lesions associated with treponematosis in skeletons from archaeological contexts since the Late Archaic Period (ca. 3.000- 400 BCE) to the Late Intermediate Period (ca. 1.000-1.400 CE) in Central Chile. Table 1. Sample distribution by age-range, sex and cultural periods Skeletal sample Table 2. Diagnostic criteria for osteological signs associated with Treponematosis N N N N N 14 13 1 4 8 1 1 0 0 1 32 26 6 13 13 Late Intermediate Period (ca. 1000 - 1400 CE) 38 38 0 13 22 Total 85 78 7 30 44 Late Archaic (ca. 3.000 - 400 BCE) First Ceramic Societies (ca. 800 BCE - 200 CE) Early Ceramic Period (ca. 0/200 - 1000/1200 CE) Diagnostic Criteria Total Adults No-adults Females Males Description Unique and unequivocal reactive changes of treponemal disease. The bone changes in the ectocranial cortex and Level I (pathognomonic) consist of the pathognomonic progressive changes from circumvallate cavitation, stellate scarring, to advanced contiguous lesions (caries sicca). Reactive changes very common to, but not exclusive of, treponemal disease (‘sabre shins’ or ‘boomerang leg’), and/or some combination of discrete (nodal) cavitating lesions on the long bones or clavicles with or without remodeling of the bone around the nose and palate (goundou/gangosa). Level II (indicative) Commensurate with treponemal disease and consists of Level III (consistent with) non-cavitating nodes, accompanied by reactive changes (periostosis) on at least one other bone. Figure 1. Archaeological sites of Central Chile with paleopathological signs related to treponematosis MATERIAL AND METHODS The archaeological sites cover a chronological range from 3000 BCE to 1400 CE (Figure 1; Table 1). These sites are located in valleys with watercourses (rivers and paleolagoons) and in the Pacific coast. We studied non-adult (N= 7) and adult skeletons (N= 78) through a macroscopic evaluation (Table 1). The sample is composed by individuals with craniums, individuals with cranium plus postcranium, and individuals only with appendicular skeleton. The paleopathological signs were classified following a diagnostic criterion based on the hierarchy of the lesions in three levels (Table 2), according to Betsinger et al. (2017). The individuals comes from two bioanthropological collections deposited in the University of Chile and in the National Museum of Natural History (Santiago, Chile). 1 Lesion I (cranium): Superficial cavities with concave walls, sharp edges (Figure 4.1), and circumvallate cavities surrounded by a depression or wall-like ridge; minor endocranial changes () Lesion II: Reactive changes in long bones, osteolytic lesions, cloacas, sequestrum, involucrum (Figure 4.2), enlarged tibia diaphysis with anteroposterior bending (sabre shin) (Figure 4.4) Cranium Lesions RESULTS Adult-male, Early Ceramic Period Adult-female, Early Ceramic Period Lesion III: Different types of periostitis in long bones (Figure 4.3) Right femora Right humerus Right ulna 2 Adult, Late Archaic Period 100,0 93,10 Left cavicle Adult-female, Late Archaic Period 90,0 No-adult, Early Ceramic Period Adult-male Late Intermediate Period 72,41 70,0 Percentage 3 Post-cranium Lesions Adult-male, Late Intermediate Period 80,0 60,0 Level I 50,0 44,83 Level II 40,0 Level III 30,0 25,00 Level I + II 21,74 20,0 16,67 16,67 16,13 10,0 4 0,0 Late Archaic Adult-female, Early Ceramic Period No-adult, Early Ceramic Period Figure 2. Distribution of the individuals by diagnostic levels First Ceramic Early Ceramic Late Intermediate Societies Period Period Cultural Periods of Central Chile Figure 3. Percentage of diagnostic levels according to the chronology Adult-male, Early Ceramic Period Figure 4. Paleopathological signs observed in Chile Central sample DISCUSSION Skeletal lesions caused by treponemal infection are not specific to this family of diseases (Ortner, 2003), and therefore discriminating between treponematosis and other diseases is difficult. However, the presence of individuals with the three types of diagnostic lesions (I, II and III) allows us to propose the existence of this pathogen in non-adults and adults from Central Chile, at least since the Late Archaic Period. We propose that the subspecies of treponeme might related to yaws or veneral syphilis, because the osteological pattern of the lesions observed in the sample. Likewise, the Mediterranean-type climate of this region with cold and rainy months during the winter season is not compatible with bejel, but it is with the other two variants. Probably the factors that contributed to the permanence and transmission of this disease correspond to a population increase 3.000 years ago, an increase in sedentary lifestyles, and contact between communities from different environments and latitudes of the macro region. References: Allison, M.J., Focacci, G., Fouant, M., Cebelin, M., 1982. La sífilis, ¿Una enfermedad americana? Chungara 9, 275–284. Aspillaga, E., Castro, M., Rodríguez, M., & Ocampo, C. Paleopatología y estilo de vida: el ejemplo de los Chono. Magallania 34(1):77-85, 2006. Baker, B. J., Crane-Kramer, G., Dee, M. W., et al. (2020) Advancing the understanding of treponemal disease in the past and present. Am J Phys Anthropol, 1-37. Betsinger, T. K., Smith, M. O., Helms Thorson, L. J., & Williams, L. L. 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