[Oxyuriasis and prehistoric migrations]

Parasite findings in archeological material have made it possible to trace the dispersion of infectious agents and their human hosts in ancient times. These findings allow us to re-examine theories proposed at the beginning of the century concerning transpacific contacts that Asian populations may have had with South America. This has been the case, for example, with hookworm eggs found in archeological material dating up to 7,000 years before present. Because of the increase in scientific production in this area, it has now become necessary to undertake syntheses that assess the state of the art and propose workable paleoepidemological models of the prehistoric dispersion of human parasitoses. Based on findings of Enterobius vermicularis eggs in archeological material in the Americas, the present study is an effort in this direction. Unlike the hookworm, the pinworm does not require a soil cycle in order to be transmitted from one host to another, thereby meaning that its persistence in a given human population does not depend on climatic conditions. Thus, it could have been brought from the old to the new continent, possibly by human migrations across the Bering Strait. This may explain the greater geographical dispersion and dissemination of these findings in North America from 10,000 yrs B.P. till today. In South America, on the other hand, archeological findings have only confirmed existence of Enterobius vermicularis eggs within the Andean region, with findings located specifically in Chile and northern Argentina. Although a large number of samples have been examined, no such eggs have been found in coprolites in Brazil. The paper discusses models that account for the known distribution of this parasitosis in prehistoric populations.