Rheumatic diseases in the ancient Americas: the skeletal manifestations of treponematoses.

INTRODUCTION: The effect of rheumatic and infectious diseases on skeletal remains provides an important source of information for knowledge of contemporary medicine. Few pathologic conditions have attracted so much interest as treponematoses. One of these, syphilis, was the most feared venereal disease throughout the civilized world until the introduction of penicillin in the 20th century. OBJECTIVE: To describe paleopathological and ceramic illustrations of treponematoses in ancient Mexico. MATERIALS AND METHODS: Paleopathological and ceramic material examples from the National Institute of Anthropology and History of Mexico were reviewed. RESULTS: A unique paleopathologic site for treponemal diseases comprises the La Candelaria Cave skeletal collection from northern Mexico. The cave was used as a burial site and contained the bones of at least 83 adults and 33 subadults. Fifty-one percent of the recovered skulls possess erosions of the vault consistent with treponematoses. Some of these exhibit the impressive frontal bone lytic changes with irregular borders typical of caries sicca. In addition, periostosis of the long bones was found in up to 88% of the study sample, including 6 examples of saber-shin deformity of tibias. Radiocarbon dating (-C) of a bone retrieved from the cave ranges from 1100 to 1300 A.D. Additionally, a Pre-Hispanic ceramic figurine from the Mexican state of Nayarit depicting a lame man with multiple nodular skin lesions that suggest gummatous treponemal infection is described. CONCLUSIONS: These ancient specimens reinforce the notion that treponemal infection was present on the American Continent before European penetration of the New World. These very advanced paleopathologic lesions and ceramic representations demonstrate the degree to which these diseases wrought devastation before the antibiotic era. In ancient times, treponematoses were true rheumatic diseases that produced profound skeletal abnormalities marked by periosteal accretion and bone destruction.

POPULATION GENETICS. Genomic evidence for the Pleistocene and recent population history of Native Americans.

How and when the Americas were populated remains contentious. Using ancient and modern genome-wide data, we found that the ancestors of all present-day Native Americans, including Athabascans and Amerindians, entered the Americas as a single migration wave from Siberia no earlier than 23 thousand years ago (ka) and after no more than an 8000-year isolation period in Beringia. After their arrival to the Americas, ancestral Native Americans diversified into two basal genetic branches around 13 ka, one that is now dispersed across North and South America and the other restricted to North America. Subsequent gene flow resulted in some Native Americans sharing ancestry with present-day East Asians (including Siberians) and, more distantly, Australo-Melanesians. Putative "Paleoamerican" relict populations, including the historical Mexican Pericúes and South American Fuego-Patagonians, are not directly related to modern Australo-Melanesians as suggested by the Paleoamerican Model.