Sweden is a country with a low prevalence of human lymphotropic T-cell virus (HTLV) infection, estimated at < 0.005%, but the infection rate is notably higher in specific risk groups such as HTLV-2 among intravenous drug users (IVDU) and people originating from HTLV-1 highly endemic areas. Thus, in the most recent study from 2012, the prevalence of HTLV-2 among IVDU in Stockholm was 3.2%. However, much of the epidemiological data on HTLV in Sweden stems from studies conducted primarily between the 1990s and 2007, and the impact of migration to Sweden during the past 15 years has not been evaluated. Despite Sweden\'s status as a country with generally low prevalence of HTLV, it is prudent to anticipate and prepare for several potential challenges associated with HTLV infection in the future. Proactive measures to enhance awareness, alongside strategies to curtail transmission and mitigate complications, are crucial for addressing this relatively rare, but significant health issue. In this work, we review the current epidemiological knowledge about HTLV in Sweden and discuss future Swedish perspectives.

Human T-cell leukemia virus type 1 (HTLV-1) can cause HTLV-1 Associated Myelopathy/Tropical Spastic Paraparesis (HAM/TSP). Current treatment options for HAM/TSP are limited. We present a woman with rapidly-progressive HAM/TSP with significant, sustained clinical improvement following initiation of mycophenolate mofetil (MMA). Peripheral blood mononuclear cells from the patient, her asymptomatic carrier husband and eight healthy controls were isolated. Frequencies of T-cell populations upon exposure to low and high MMA concentrations and differences in proliferation were analyzed using flow cytometry and a CSFE-proliferation assay. Characterization of T-cell function and proliferation showed higher levels of GranzymeB in HTLV-1+ donors. The improvement and stability of symptoms in this patient with HAM/TSP following MMA initiation requires further study as a potential treatment for HAM/TSP.

Nearly 2-3% of those 10 to 20 million individuals infected with the Human T-cell lymphotropic virus type-1 (HTLV-1); are predisposed to developing HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It is a neuro-inflammatory disease; differentiated from multiple sclerosis based on the presence of typical neurologic symptoms, confirmation of HTLV-1 infection, and other molecular biomarkers.
A brief review of the epidemiology, host immune responses, and molecular pathogenesis of HAM/TSP is followed by detailed discussions about the host-related risk factors for developing HAM/TSP and success/failure stories of the attempted management strategies.
Currently, there is no effective treatment for HAM/TSP. Anti-retroviral therapy, peculiar cytokines (IFN-α), some anti-oxidants, and allograft bone marrow transplantation have been used for treating these patients with limited success. Under current conditions, asymptomatic carriers should be examined periodically by a neurologist for early signs of spinal cord injury. Then it is crucial to determine the progress rate to adapt the best management plan for each patient. Corticosteroid therapy is most beneficial in those with acute myelitis. However, slow-progressing patients are best managed using a combination of symptomatic and physical therapy. Additionally, preventive measures should be taken to decrease further spread of HTLV-1 infection.

A large number of causative agents can result in spinal cord disorders in the tropics including etiologies similar to those of temperate regions such as trauma, spinal bone and disc lesions, tumors, epidural abscess, and congenital malformations. Yet infectious and nutritional disorders differ in their higher prevalence in tropical regions including Pott\'s disease; brucellosis; neuroborreliosis; various parasitic diseases such as schistosomiasis, neurocysticercosis, and eosinophilic meningitis. Notably, the retrovirus HTLV-1 is the causeof tropical spastic paraparesis/paraplegia or TSP. Nutritional causes of TSP include vitamin B and folate deficiencies, while endemic clusters of konzo and tropical ataxic myeloneuropathy occur in Africa, along with malnutrition and excessive consumption of cyanide-containing bitter cassava. Other toxic etiologies of TSP include lathyrism and fluorosis. Nutritional forms of myelopathy are associated often with optic and sensory neuropathy, hence the name tropical myeloneuropathies. Acute transverse myelopathy, seen in association with vaccination, infections, and fibrocartilaginous embolism of the nucleus pulposus, can be ubiquitous. Multiple sclerosis and optic myelopathy occur in the tropics but with lesser prevalence than in temperate regions. The advent of modern imaging in the tropics, including computed tomography and magnetic resonance imaging, has allowed better diagnosis and treatment of these conditions that are a frequent cause of death and disability. This chapter provides an overview of TSP emphasizing the most common causes with clues to diagnosis and effective therapy.

UNASSIGNED: HTLV-1 is responsible for two important diseases, HAM/TSP and ATLL. Approximately 10 to 20 million people are infected with HTLV-1 worldwide. Identifying altered genes in different cancers is crucial for finding potential treatment strategies. One of the proteins of the RAS/MAPK signaling pathway is MEK1, which is made from the MAP2K1 gene. The effects of the MAP2K1 gene on the MAPK signaling pathway are not yet fully elucidated. The current study aims to determine the MAP2K1 gene mutations and the level of MAP2K1 gene expression in ATLL patients compared to healthy individuals.
UNASSIGNED: Ten ATLL and 10 healthy control individuals were investigated in this study. We used ELISA test to screen anti-HTLV-I antibodies and PCR for confirmation of infection. Then, we extracted total RNA from fresh whole blood, and cDNA was synthesized. The expression levels of the MAP2K1 gene were examined by qRT-PCR, and to check possible mutations in the MAP2K1 gene; all samples were sequenced and analyzed by BioEdite Software.
UNASSIGNED: MAP2K1 gene expression in the ATLL group was significantly higher than in the healthy control (P=0.001). The mutational sequencing analysis showed nucleotide 212 (S→R) change and identification mutations at different nucleotides that were entirely different from the nucleotide mutations defined in the UniProt database.
UNASSIGNED: These results could be a perspective in the prevention, prognosis, and targeted treatment of diseases in which the MAP2K1 gene plays a vital role.

To determine the prevalence of signs and symptoms of HTLV-1 and 2 infection in paediatric patients.
We included cohort, case-control and descriptive observational studies that reported the prevalence of signs and symptoms of HTLV-1 and 2 infections in paediatric patients. Searches were performed in MEDLINE® (Ovid), EMBASE and LILACS from inception to the present, and we saturated information with other sources of published and unpublished literature. We decided not to perform meta-analysis according to heterogeneity.
A total of eight studies met the inclusion criteria for qualitative analysis. No studies of HTLV-2 were found. Females predominated and there was vertical transmission in nearly 100% of cases. Infective dermatitis was a common manifestation of HTLV in paediatric patients. In addition, persistent hyperreflexia, clonus and the Babinski sign were early neurological alterations observed in patients carrying the virus.
HTLV screening is recommended in patients presenting infective dermatitis, persistent hyperreflexia, walking disturbances and in those who come from endemic zones.

BACKGROUND: The peripartum period is both a highly vulnerable stage and a significant indicator of a population\'s health status. Interest is increasing in human T-cell lymphotropic virus type-1 (HTLV-1) transmission due to its adverse health impacts. However, nationally representative data on HTLV-1 that are important for health planning are unavailable for this subpopulation.
OBJECTIVE: This study aimed to conduct a pooled estimate of HTLV-1 prevalence among pregnant women in Nigeria to quantify its clinical burden and public health implications.
METHODS: This systematic review was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analysis 2020 statement.
RESULTS: After a systematic review of the Nigerian literature, 12 studies (2,821 pregnant or postnatal women) were included in the final evidence synthesis. The estimated HTLV-1 prevalence in Nigerian peripartum women following a positive screening test by enzyme-linked immunosorbent assay was 5.44% (95% confidence interval [CI], 3.16%-9.20%). A subgroup analysis of the 2 major regions showed a slightly higher prevalence in the Western versus Southern region (5.55% [95% CI, 2.49%-11.87%]; and 4.91% [95% CI, 2.11%-11.02%]; P=0.84). However, a subgroup analysis by geopolitical zone revealed that Southwestern and Northwestern Nigeria had the highest prevalence (9.23% [95% CI, 4.35%-18.55%; I2=93%] and 7.15% [95% CI, 1.54%-27.54%]; I2=92%). Our decade-old subgroup analysis found inconsistencies in the HTLV-1 prevalence. Furthermore, our literature review revealed a prevalence of HTLV infection among patients with various clinical types of lymphomas/leukemias and myelopathy of 2%-22%.
CONCLUSIONS: These findings have important implications in defining the epidemiological patterns of HTLV-1 infection in Nigeria. They also suggest the presence of HTLV-endemic clusters near low-endemic areas, even within the same geopolitical zones.

(1) Background: Tropical spastic paraparesis (TSP/HAM) associated with the T cell lymphotropic virus in type I humans (HTLV-1) is a slow, chronic, and progressive disease that causes balance changes. TSP/HAM diagnosis can be classified as probable, possible, and definite. We compared the static balance control of HTLV-1-infected patients with different TSP/HAM diagnosis. (2) Methods: Our sample consisted of 13 participants infected with HTLV-1 and 16 healthy participants. The center of pressure was recorded using a force platform with open and closed eyes. We divided the recordings into three intervals, period T1 (corresponds to the first 10 s); period T2 (from 10 to 45 s); period T3 (from 45 to 55 s). (3) Results: Eight participants infected with HTLV-1 were classified as probable TSP/HAM and five participants infected with HTLV-1 were classified as definite TSP/HAM. There was a significant increase in postural instability in patients with definite PET/MAH considering the structural and global variables of body sway compared to the control and the probable TSP/HAM. (4) Conclusions: We concluded that the severity of balance is directly related to the degree of signs and symptoms of TSP/HAM.

Human T cell lymphotropic virus (HTLV)-1-associated myelopathy is a chronic, disabling inflammatory disorder of the spinal cord caused by HTLV-1 infection. The diagnosis of HTLV-1-associated myelopathy (HAM) is based on clinical and laboratorial findings. The disease is characterized by the presence of spastic paraparesis associated with detection of anti-HTLV-1 antibodies or HTLV-1 genomes in blood and cerebrospinal fluid (CSF). New inflammatory markers have been proposed for the diagnosis and assessment of the prognosis of HAM. We reviewed the laboratory diagnostic and potential surrogate markers for HAM. The serological screening tests for detection of anti-HTLV-1/2 antibodies are highly sensitive and specific, but confirmation and typing of HTLV-1 or HTLV-2 infection by other serological or molecular methods are essential. Detection of intrathecal anti-HTLV-1 antibodies and quantification of the HTLV-1 provirus in CSF provide additional evidence for diagnosis especially in atypical cases or where alternative causes of neuroinflammation cannot be excluded. The CXC motif chemokine ligand 10 and neopterin in serum and CSF are now emerging as inflammatory markers with prognostic value and for HAM monitoring and management. In addition, measures of neurodegeneration, such as neurofilament light chain in the CSF and blood, may also contribute to the HAM prognosis. This review is useful for clinicians and researchers evaluating potential benefits and limitations of each biomarker in clinical practice. The advent of new markers makes it necessary to update the criteria for the best evidence-based approach and for worldwide consensus regarding the use of diagnostic and surrogate markers for HAM.

The origin of brain white matter lesion found in HTLV-1-associated myelopathy (HAM/TSP) remains undefined. We investigated the association between white matter lesions in HAM/TSP with cardiovascular risk factors. The group of 40 patients with HAM/TSP included 60% females and mean age of 58.6 ± 8 years old. The probability of 10-year cardiovascular disease was low in 53%, moderate in 38%, and high in 10% of the patients. There was no difference between the cardiovascular risk factors in HAM/TSP patients with and without brain lesions (p > 0.05). Our data suggest that the brain white matter abnormalities are not associated to increased cardiovascular risk in HAM/TSP.