China
Africa
Explore chapters and articles related to this topic
The Viruses
Published in Julius P. Kreier, Infection, Resistance, and Immunity, 2022
HTLV-1 is also implicated as the causative agent in the neurological disorder HTLV-1-associated myelopathy (HAM) or tropical spastic paraparesis (TSP). HAM/TSP is a chronic demyelinating disease characterized by weakness and spasticity of the extremities, hyperreflexia, and mild peripheral sensory loss. The pathogenesis of HAM/TSP is not fully understood, but it appears to be distinct from ATL. Development of the myelopathy occurs within several years following infection, whereas development of the leukemia normally requires twenty to thirty years. HTLV-1 provirus is polyclonally integrated in the peripheral blood cells of HAM/TSP patients as opposed to mono or oligoclonally integrated with ATL. There are approximately three-times more infected cells in HAM/TSP patients than in asymptomatic carriers, and there are also higher titers of anti-HTLV-1 antibodies in the serum and CSF. It has been suggested that HAM/TSP is an autoimmune disease resulting from immune dysregulation. HTLV-1-infected patients exhibit an increased incidence of a variety of immune-mediated disorders. However, these disorders are less clearly associated with HTLV-1 than ATL and HAM/TSP.
Spinal Cord Disease
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
HTLV is transmitted via breast milk (vertical transmission), sexual contact, and contaminated blood products. The virus directly promotes an inflammatory response in the CNS. There is possible molecular mimicry leading to secondary autoimmune-mediated tissue damage. Clinical features include: Indolent spastic weakness.Transverse myelopathy syndrome with lower extremity sensory loss (both dorsal columns and spinothalamic tracts), prominent bowel/bladder dysfunction.Progression over years: Thoracic spine is most commonly affected.First few years of clinical symptoms can be more rapidly progressive with a plateau or gradual progression in subsequent years.
Introduction to Retro Virology and Retroviral Testing
Published in Niel T. Constantine, Johnny D. Callahan, Douglas M. Watts, Retroviral Testing, 2020
Niel T. Constantine, Johnny D. Callahan, Douglas M. Watts
The importance and epidemiology of infection associated with the HTLVs have only been recognized since the 1980s. Endemic areas of HTLV-I infection include Japan; the Caribbean islands; the southeastern U.S.; and parts of South America, Italy, and Africa. The prevalence of HTLV-I infection is reported to be 5 to 10% in some areas of Japan. Little information is presently available on the epidemiology of HTLV-II infection, although very high rates have been identified in intravenous (i.v.) drug addicts in the U.S. The routes of transmission of the HTLVs are similar to those of the HIVs, namely via blood transfusion, vertically from mother to fetus, and sexually. Blood transfusion is the most efficient mode, with reported seroconversion rates of 35 to 60% following exposure to contaminated blood. Infection by the HTLVs has been associated with a variety of diseases including adult T cell leukemia/lymphoma (ATLL), HTLV-I associated myelopathy/tropical spastic paraparesis (HAM/ TSP), and hairy cell leukemia.
HTLV-I associated bronchioloalveolar disorder (HABA): disease concept and differential diagnosis of an unsolved disease entity
Published in Expert Review of Anti-infective Therapy, 2023
Akihiro Ohmoto, Shigeo Fuji, Satoshi Kohmo, Kaoruko Katsura
HTLV-1-associated myelopathy (HAM) or tropical spastic paraparesis (TSP) is most well-known non-neoplastic disease related to HTLV-1 infection, and is characterized by chronic inflammation of the spinal cord causing weakness or paralysis of the legs, lower back pain, and urinary symptoms [6]. Another complication of HTLV-1 is HTLV-1 uveitis, also known as HTLV-1-associated ocular disease, which is characterized by infiltration of inflammatory cells into the vitreous [7]. However, HAM/TSP and HTLV-1 uveitis are rare and non-lethal complications that do not sufficiently explain the significant impact of HTLV-1 infection on overall mortality. HTLV-1-associated bronchioloalveolar disorder (HABA) is an immune-mediated state induced by HTVL-1. Currently, we do not have adequate information regarding the incidence and clinical features of HABA. The disease concept is not solid, and there are no clinical guidelines. Furthermore, reports on HABA are limited and have been chiefly published by researchers from endemic areas including Japan. Therefore, international recognition and interest in HABA is expected to be deficient.
Biomedical and genetic characteristics of the Ryukyuans: demographic history, diseases and physical and physiological traits
Published in Annals of Human Biology, 2019
Kae Koganebuchi, Ryosuke Kimura
Generally, the regional difference in the prevalence of HTLV-1-related diseases is attributed to the difference in the frequency of the carriers. However, the difference in clinical features may be partly caused by the HTLV-1 genotype. The viral gene expression and the onset and development of ATL depend on a transcriptional regulator encoded by pX (Tax). It has been reported that the distribution of the HTLV-1 Tax genotypes in Ryukyuan ALT patients (taxA, 44%; taxB, 56%) differed from that in patients from Kagoshima Prefecture in southern Kyushu (taxA, 10%; taxB, 90%) and that the estimated hazard ratio of taxA compared with taxB was 2.68 (Sakihama et al. 2017). These findings suggest that the tax genotype could explain the clinical features of aggressive ATL in Okinawa Prefecture. In addition, it has been shown that, compared with those in other regions of Japan, aggressive ALT in Okinawa Prefecture is associated with a higher proportion of patients over 90 years old, a poorer outcome and a higher prevalence of strongyloidiasis (Nishi et al. 2016).
Assessment of risk factors associated with HTLV-1/-2 infection among people living with HIV/AIDS in Bauchi State, Nigeria
Published in Alexandria Journal of Medicine, 2020
Adamu Babayo, Idris Nasir Abdullahi, Mansur Bala Safiyanu, Hafeez Aderinsayo Adekola, Jamila Nasir Usman
Human T-cell lymphotropic virus (HTLV) is associated with shorter survival of HIV coinfected persons due to masked immunosuppression [1]. Coinfection of HTLV and HIV is common in areas endemic for HTLV because these viruses have similar transmission routes, such as unprotected sexual intercourse, breastfeeding, blood transfusion and organ/tissue transplantation, and injectable drug use [1]. Studies suggest that people living with HIV (PLWHIV) infected with HTLV-1 are more likely to develop myelopathies and neurological disease [2]. However, the effect of HTLV-2 in HIV-positive individuals is unclear [3]. In addition, coinfection may mask the diagnosis of acquired immunodeficiency syndrome (AIDS), since CD4 + T-cell counts significantly increase in affected persons [4,5].