Molecular Identification And Analysis Of Treponematosis (Syphilis, Bejel, Yaws, Or Pinta) In Ancient Mummified Remains From Northern Chile And Southern Peru

Abstract

The sequencing of Treponema pallidum subsp. pallidum, the bacterium that causes syphilis, and the identification of a family of 12 genes with sequence similarity that allows scientists to distinguish between treponemal subtypes has opened up a new line of inquiry for biological anthropologists. This research contributes genetic evidence of pre-contact treponematosis in the Americas; by combining osteological and molecular evidence with data on environment and cultural practices, it also furthers our knowledge of human-pathogen interaction. This research assessed the presence of treponematosis, a bacterial spirochete, in the DNA of skeletal and mummified human remains from northern Chilean cemeteries dating from 5000 BC to AD 1100. The objectives were to: (1) determine whether treponemal DNA could be successfully recovered, amplified, and identified by subspecies from ancient bone and tissue, (2) compare any ancient sequences generated to the modern strains present in the National Center for Biotechnology Information (NCBI) GenBank database, (3) test the null hypothesis that treponematosis was not present in the New World before European contact, and (4) explore which cultural factors may have contributed to the spread of treponematosis in these groups. This research established a foundation for future treponemal studies through the development of primers and protocols for the analysis of ancient treponemes. The results of this study suggest that the inhabitants of this region suffered from a systemic bacterial infection, likely a chronic form of non-venereal treponematosis: yaws or bejel. Potential treponemal DNA was recovered from bone in an individual dated 202 cal BC--cal AD 3 from the Azapa valley. An investigation of Chinchorro artificial mummification suggests that their mortuary practice likely did not result in a higher frequency of treponematosis, as compared to later and inland groups. Rather, status and socioeconomic factors may have played a role in differential infection rates between those mummified in complex styles and those in natural or less complex styles. Further analysis of human remains with suspected treponemal lesions is necessary to reconstruct the history of treponematosis, improve our understanding of their pathogenesis, and guide scientists in developing preventative measures.