Geographic-Specific Genotypes or Topotypes of Human T-Cell Lymphotropic Virus Type I As Markers for Early and Recent Migrations of Human Populations

Abstract

Publisher Summary Kuru is one of the better-known paradigms of “place diseases,” or diseases occurring in high incidence in geographically restricted or delimited regions. From the study of kuru among the stone age fore in the Eastern Highlands of Papua, New Guinea, came the discovery of unconventional agents or slow viruses that cause neurodegenerative diseases in humans. In a similar fashion, the study of another place disease, a fulminating hematological malignancy in southwestern Japan, called adult T-cell leukemiailymphoma, led to the discovery of and etiological association with an exogenous replication-competent human retrovirus, human T-cell lymphotropic virus type I (HTLV-I). This initial frontier of HTLV-I research was expanded by the serendipitous discovery that endemic tropical spastic paraparesis, also known as Jamaican neuropathy and paraparesia espastica el Pucifico, another place disease in the Caribbean basin and Colombia, was also caused by HTLV-I. A clinically indistinguishable spastic myelopathy, designated HTLV-I-associated myelopathy, was later recognized among HTLV-I-seropositive individuals in southern Japan, and presently, HTLV-I-associated myelopathy and HTLV-I-positive tropical spastic paraparesis are considered to be the same disease. The study of diseases in populations isolated by the virtue of geography, culture, and/or genetics can also provide insights into the evolution and dissemination of the etiological agent. From the studies of HTLV-I infection in an isolated recently contacted group in the fringe highlands of Papua, New Guinea, and among the lifelong residents of the Solomon Islands has come an augmented perspective on the emergence, evolution, and global dissemination of this lymphotropic retrovirus. In addition, these studies in Melanesia have led to the realization that HTLV-I may, in certain instances, serve as a biological marker for the early and recent migrations of human populations.