On the etiology of tropical spastic paraparesis and human T-cell lymphotropic virus-I-associated myelopathy.
The purpose of this review is to present some concepts on the etiology of tropical spastic paraparesis or human T-cell lymphotropic virus-I (HTLV-I)-associated myelopathy (TSP/HAM). The large number of syndromes that have been associated with HTLV-I (60 to date), the existence of TSP/HAM cases associated with other retroviruses (human immunodeficiency virus-2 [HIV-2], HTLV-II), the existence of many TSPs without HTLV-I, and the evidence of clear epidemiologic contradictions in TSP/HAM indicate that the etiopathogenesis of TSP/HAM is not yet clear. Tropical spastic paraparesis/HAM affects patients of all human ethnic groups, but usually in well localized and relatively isolated geographic regions where HTLV-I has been endemic for a long time. Environmental factors and geographic locations appear to be critical factors. Because the neuropathology of TSP/HAM suggests a toxometabolic, rather than a viral cause, it is proposed that an intoxication similar to neurolathyrism could account for some of TSP/HAM cases, mainly in tropical and subtropical countries. If this were the case, HTLV-I could be a cofactor or act as a bystander. it is possible that co-infection with another agent is necessary to produce TSP/HAM and most of the syndromes associated with HTLV-I.
Zaninovic
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Emeritus Professor, Clinical Neurology, School of Medicine, Valle University, Cali, Colombia. vlazani@mafalda.univalle.edu.co
D000818:Animals; D000914:Antibodies, Viral / Q000097:blood; D001803:Blood Transfusion; D001921:Brain / Q000473:pathology; D004781:Environmental Exposure; D007887:Fabaceae; D015368:Human T-lymphotropic virus 1 / Q000276:immunology; D006801:Humans; D015493:Paraparesis, Tropical Spastic / Q000453:epidemiology / Q000209:etiology* / Q000276:immunology / Q000821:virology; D010946:Plants, Medicinal; D051381:Rats; D012190:Retroviridae; D013116:Spinal Cord / Q000473:pathology
D000914:Antibodies, Viral