Browsing by Autor "Kazuo Tajima"

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Endemic HTLV in Japan and South America with special reference to mongoloid dispersal from Asia to the Andes
(1998) Kazuo Tajima; Shunro Sonoda; Luis Cartier; Vladimir Zaninovic; Láutaro Núñez; Luis Hurtado; Sonia Guillén; José Edgardo Dipierri; Toshiro Takezaki; Toshinobu Fujiyoshi
Se ha estimado que existe 1,2 millones de portadores del virus humano de la leucemia T tipo I (HTLV I) en todo el Japón, donde la incidencia de leucemia a linfocitos T del adulto es la más alta del mundo. Si se compara la distribución geográfica del HTLV-I y HTLV-II entre los portadores del virus en Sudamérica, se observa que el primero (HTLV-I) está limitado al área andina y que de norte a sur incluye: Colombia, Ecuador, Perú, Bolivia, Chile y Argentina. Mientras que el segundo (HTLV-II), se expande entre el resto de los nativos sudamericanos desde el borde del Caribe al extremo sur de la Patagonia. El origen tanto del HTLV-I como HTLV-II en estas regiones no ha sido completamente aclarado, pero muy probablemente se liga a la historia de la dispersión humana en este continente, donde en algún momento se crearon grupos con una exclusiva localización geográfica que transmitieron el virus de madres a hijos y de hombre a mujer bajo condiciones naturales. Para explicar esta transposición única del HTLV?I desde los asiáticos del Japón a los andinos de Sudamérica se han desarrollado diferentes modelos hipotéticos de esta histórica migración de los portadores de HTLV-I y HTLV-II. La similitud en el antecedente genético que muestran los japoneses del sur y los pueblos andinos de Sudamérica sugiere una hipótesis migratoria plausible, pero que no encuentra general aceptación entre antropólogos y arqueólogos. Suponemos que los portadores de HTLV-I llegaron a América del Sur y a los Andes a través de una ruta transpacífica, mucho después que los portadores de HTLV-II venidos de Asia arribaran al continente Sudamericano.
EPIDEMIC PATTERN OF HTLV IN PANPACIFIC AREAS WITH SPECIAL REFERENCE TO MONGOLOID DISPERSAL
(Lippincott Williams & Wilkins, 1999) Kazuo Tajima; Luis Cartier; Vladimir Zaninovic; Luis Hurtado; Sonia Guillén; José Edgardo Dipierri; Masanori Hayami; Toshinobu Fujiyoshi; Shunro Sonoda
O-47 A worldwide natural clustering of HTLV-I/II would have been modified by a modern human migration with unique cultural conditions. Based on review of strict confirmatory assays on HTLV-I/II antibodies among native Mongoloid people in Pan-Pacific areas, HTLV-I is mainly detected among southwestern Japanese and Andean, including Colombian, Peruvian, Bolivian, Chilean and Argentinean, but HTLV-II is broadly spread among native people throughout the Central and South America, including Panama, Colombia, Venezuela, Brazil, Paraguay, Argentina and Chile. Furthermore, a different subtype of HTLV-I is clustered among Australoids (native Melanesians) in Oceania, including Papua New Guinea, North Australia and neighboring islands, but it is never clustered among Polynesians. An origin of HTLV-I/II among Mongoloids and Australoids is not well understood, but is probably linked to a history of human dispersal, and a geographical clustering is strongly associated with a putatively high mother-to-child and man-to-woman transmission of the virus under natural condition of each group. To investigate a unique distribution of HTLV-I among Japanese in Asia and Andean in South America, comprehensive information on immunogenetic variation among native people in Pan Pacific areas may give a hint to disclose a relationship between Japanese and Andean ancestors. The most recent genetic studies on Andean mummies could provide an explanatory evidence on migration history of Asian Mongoloid.
PHYLOGENETIC ANALYSES OF 11 HTLV-I FROM AMERINDIANS OF SOUTH AMERICA
(Lippincott Williams & Wilkins, 1999) Masahiro Yamashita; Sadayuki Ohkura; Shunro Sonoda; Luis Hurtado Gómez; Luis Caritier; Sonia Guillén; José Edgardo Dipierri; Tomoyuki Miura; Kazuo Tajima; Masanori Hayami
P112 In South America, HTLV-I has been identified not only among immigrants who came to the continent during a few centuries (Europeans, Africans and Japanese) but also among Amerindians, whose ancestors are believed to have migrated from Asia more than ten thousands years ago. To gain new insights as to the origin of HTLV-I in South America, we phylogenetically characterized 11 HTLV-Is from Amerindians (two from Argentina, two from Bolivia, six from Chile and one from Peru). A part of the LTR region was sequenced and subjected to phylogenetic analyses for comparison with HTLV-Is of various geographical origins. Phylogenetic trees indicated that all the new HTLV-Is belonged to the Transcontinental (A) subgroup of the Cosmopolitan group. These new isolates differed from HTLV-I in Africa with the exception of two Bolivian HTLV-Is which are related to South African HTLV-Is. In the subgroup A, they were also distinct from Japanese HTLV-Is. This result as well as the fact that the samples were obtained from Amerindians who are ethnically segregated suggest that HTLV-I of Amerindians are not imported from Africa nor Japan but may be an indigenous virus to South America. On the other hand, the majority of HTLV-I found in other ethnic populations of South America (whites, blacks and mestizos) exhibits closer similarities to HTLV-I of Amerindians than those of Japan and Africa. This suggests that HTLV-I of Amerindians spread to new residents of the continent and does not support the prevailing hypothesis that recent introduction of African HTLV-I is the sole origin of HTLV-I in South America.