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Archives of Virology Nov 2021Human T-lymphotropic virus type 1 (HTLV-1) was the first human retrovirus described. The viral factors involved in the different clinical manifestations of infected...
Human T-lymphotropic virus type 1 (HTLV-1) was the first human retrovirus described. The viral factors involved in the different clinical manifestations of infected individuals are still unknown, and in this sense, sequencing technologies can support viral genome studies, contributing to a better understanding of infection outcome. Currently, several sequencing technologies are available with different approaches. To understand the methodological advances in the HTLV-1 field, it is necessary to organize a synthesis by a rigorous review. This systematic literature review describes different technologies used to generate HTLV-1 sequences. The review follows the PRISMA guidelines, and the search for articles was performed in PubMed, Lilacs, Embase, and SciELO databases. From the 574 articles found in search, 62 were selected. The articles showed that, even with the emergence of new sequencing technologies, the traditional Sanger method continues to be the most commonly used methodology for generating HTLV-1 genome sequences. There are many questions that remain unanswered in the field of HTLV-1 research, and this reflects on the small number of studies using next-generation sequencing technologies, which could help address these gaps. The data compiled and analyzed here can help research on HTLV-1, assisting in the choice of sequencing technologies.
Topics: Brazil; Genome, Viral; HTLV-I Infections; High-Throughput Nucleotide Sequencing; Human T-lymphotropic virus 1; Humans; Sequence Analysis, RNA
PubMed: 34415436
DOI: 10.1007/s00705-021-05204-w -
Scientific Reports Jul 2021Human T-lymphotropic virus type 1 (HTLV-1) infection may cause serious disease, while pathogenicity of HTLV-2 is less certain. There are no screening or surveillance... (Meta-Analysis)
Meta-Analysis
Human T-lymphotropic virus type 1 (HTLV-1) infection may cause serious disease, while pathogenicity of HTLV-2 is less certain. There are no screening or surveillance programs for HTLV-1/-2 infection in Brazil. By performing this systematic review, we aimed to estimate the prevalence of HTLV-1/-2 infections in pregnant women in Brazil. This review included cohort and cross-sectional studies that assessed the presence of either HTLV-1/-2 infection in pregnant women in Brazil. We searched BVS/LILACS, Cochrane Library/CENTRAL, EMBASE, PubMed/MEDLINE, Scopus, Web of Science and gray literature from inception to August 2020. We identified 246 records in total. Twenty-six of those were included in the qualitative synthesis, while 17 of them were included in the meta-analysis. The prevalence of HTLV-1 in Brazilian pregnant women, as diagnosed by a positive screening test and a subsequent positive confirmatory test, was 0.32% (95% CI 0.19-1.54), while of HTLV-2 was 0.04% (95% CI 0.02-0.08). Subgroup analysis by region showed the highest prevalence in the Northeast region (0.60%; 95% CI 0.37-0.97) for HTLV-1 and in the South region (0.16%; 95% CI 0.02-1.10) for HTLV-2. The prevalence of HTLV-1 is much higher than HTLV-2 infection in pregnant Brazilian women with important differences between regions. The prevalence of both HTLV-1/-2 are higher in the Northeast compared to Center-West region.
Topics: Brazil; Female; HTLV-I Infections; HTLV-II Infections; Human T-lymphotropic virus 1; Human T-lymphotropic virus 2; Humans; Pregnancy; Pregnant Women
PubMed: 34321555
DOI: 10.1038/s41598-021-94934-7 -
Viruses May 2021The main route of mother-to-child transmission (MTCT) of human T cell leukemia virus type 1 is vertical transmission via breastfeeding. Although the most reliable method... (Meta-Analysis)
Meta-Analysis
The main route of mother-to-child transmission (MTCT) of human T cell leukemia virus type 1 is vertical transmission via breastfeeding. Although the most reliable method for preventing MCTC is exclusive formula feeding (ExFF), short-term breastfeeding (STBF) or frozen-thawed breast milk feeding (FTBMF) has been offered as an alternative method if breastfeeding is strongly desired. The aim of this review was to clarify the pooled risk ratio of MCTC of STBF and FTBMF compared with ExFF. This study was registered with PROSPERO (number 42018087317). A literature search of PubMed, CINAHL, the Cochrane Database, EMBASE, and Japanese databases through September 2018 identified 1979 articles, 10 of which met the inclusion criteria. Finally, 11 articles, including these 10 studies and the report of a recent Japanese national cohort study, were included in the meta-analysis. The pooled relative risks of STBF ≤3 months, STBF ≤6 months, and FTBMF compared with ExFF were 0.72 (95% confidence interval (CI): 0.30-1.77; = 0.48), 2.91 (95% CI: 1.69-5.03; = 0.0001), and 1.14 (95% CI: 0.20-6.50; = 0.88), respectively. This meta-analysis showed no statistical difference in the risk of MTCT between STBF ≤3 months and ExFF, but the risk of MTCT significantly increased in STBF ≤6 months.
Topics: Breast Feeding; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Infant, Newborn; Infectious Disease Transmission, Vertical; Milk, Human; Nutritional Status; Odds Ratio; Pregnancy; Pregnancy Complications, Infectious
PubMed: 34062915
DOI: 10.3390/v13050819 -
Tropical Medicine & International... Nov 2019Human T-cell lymphotropic virus type 1 (HTLV-1), the causative agent of adult T-cell leukaemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Human T-cell lymphotropic virus type 1 (HTLV-1), the causative agent of adult T-cell leukaemia/lymphoma (ATL) and HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP), is endemic in sub-Saharan Africa (SSA) and poses a high morbidity and mortality risk. Its prevalence in the general population is poorly understood. The potential for prevention motivated us to do a systematic review and meta-analysis of population-based studies to estimate the prevalence of HTLV-1 in SSA.
METHODS
A comprehensive, no-limit search was conducted in EMBASE, PubMed, Web of Science and the Cochrane Library from their inception dates to March 2019. Population-based studies presenting data on HTLV-1 in sub-Saharan Africa were included. Pooled prevalence was estimated using a random-effects meta-analysis.
RESULTS
A total of 21 studies were included, representing 42 297 participants. The pooled HTLV-1 seroprevalence was 3.19% (95% CI 2.36-4.12%) with variations across year of study. Prevalence of HTLV-1 positively correlated with year of study (β = 0.0036, P = 0.007). Participants from Central, Western and Southern Africa had a seroprevalence of 4.16% (95% CI 2.43-6.31%), 2.66% (95% CI 1.80-3.68%) and 1.56% (95% CI 0.48-3.15%), respectively.
CONCLUSIONS
Our findings suggest that HTLV-1 infection is a public health concern in SSA and highlight the need to implement effective preventive programmes and interventions aimed at reducing the burden of this common yet neglected infection.
Topics: Africa South of the Sahara; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Paraparesis, Tropical Spastic; Prevalence; Seroepidemiologic Studies
PubMed: 31465629
DOI: 10.1111/tmi.13305 -
The American Journal of Tropical... Oct 2019Human T-cell lymphotropic virus type 1 (HTLV-1) imposes a substantial disease burden in sub-Saharan Africa (SSA), which is arguably the world's largest endemic area for... (Meta-Analysis)
Meta-Analysis
Prevalence and Molecular Epidemiology of Human T-Lymphotropic Virus Type 1 among Women Attending Antenatal Clinics in Sub-Saharan Africa: A Systematic Review and Meta-Analysis.
Human T-cell lymphotropic virus type 1 (HTLV-1) imposes a substantial disease burden in sub-Saharan Africa (SSA), which is arguably the world's largest endemic area for HTLV-1. Evidence that mother-to-child transmission persists as a major mode of transmission in SSA prompted us to estimate the pooled prevalence of HTLV-1 among pregnant women throughout the region. We systematically reviewed databases including EMBASE, MEDLINE, Web of Science, and the Cochrane Database of Systemic Reviews from their inception to November 2018. We selected studies with data on HTLV-1 prevalence among pregnant women in SSA. A random effect meta-analysis was conducted on all eligible data and heterogeneity was assessed through subgroup analyses. A total of 18 studies, covering 14,079 pregnant women, were selected. The evidence base was high to moderate in quality. The pooled prevalence, per 100 women, of the 18 studies that screened HTLV-1 was 1.67 (95% CI: 1.00-2.50), a figure that masks regional variations. In Western, Central, Southern, and Eastern Africa, the numbers were 2.34 (1.68-3.09), 2.00 (0.75-3.79), 0.30 (0.10-0.57), and 0.00 (0.00-0.21), respectively. The prevalence of HTLV-1 infection among pregnant women in SSA, especially in Western and Central Africa, strengthens the case for action to implement routine screening of pregnant women for HTLV-1. Rigorous studies using confirmatory testing and molecular analysis would characterize more accurately the prevalence of this infection, consolidate the evidence base, and further guide beneficial interventions.
Topics: Africa South of the Sahara; Female; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Infectious Disease Transmission, Vertical; Molecular Epidemiology; Pregnancy; Prevalence
PubMed: 31407658
DOI: 10.4269/ajtmh.19-0182 -
Biology of Blood and Marrow... Aug 2019Human T cell lymphotropic virus type 1 (HTLV1)-associated adult T cell leukemia/lymphoma (ATLL) is an aggressive malignant disorder. Intensive conventional chemotherapy... (Meta-Analysis)
Meta-Analysis
Efficacy of Allogeneic Hematopoietic Cell Transplantation in Human T Cell Lymphotropic Virus Type 1-Associated Adult T Cell Leukemia/Lymphoma: Results of a Systematic Review/Meta-Analysis.
Human T cell lymphotropic virus type 1 (HTLV1)-associated adult T cell leukemia/lymphoma (ATLL) is an aggressive malignant disorder. Intensive conventional chemotherapy regimens and autologous hematopoietic cell transplantation (HCT) have failed to improve outcomes in ATLL. Allogeneic HCT (allo-HCT) is commonly offered as front-line consolidation despite lack of randomized controlled trials. We performed a comprehensive search of the medical literature using PubMed/Medline, EMBASE, and Cochrane reviews on September 10, 2018. We extracted data on clinical outcomes related to benefits (complete response [CR], overall survival [OS], and progression-free survival [PFS]) and harms (relapse and nonrelapse mortality [NRM]), independently by 2 authors. Our search strategy identified a total of 801 references. Nineteen studies (n = 2446 patients) were included in the systematic review; however, only 18 studies (n = 1767 patients) were included in the meta-analysis. Reduced intensity conditioning regimens were more commonly prescribed (52%). Bone marrow (50%) and peripheral blood (40%) were more frequently used as stem cell source. The pooled post-allografting CR, OS, and PFS rates were 73% (95% confidence interval [CI], 57% to 87%), 40% (95% CI, 33% to 46%), and 37% (95% CI, 27% to 48%), respectively. Pooled relapse and NRM rates were 36% (95% CI, 28% to 43%) and 29% (95% CI, 21% to 37%), respectively. The heterogeneity among the included studies was generally high. These results support the use of allo-HCT as an effective treatment for patients with ATLL, yielding pooled OS rates of 40%, but relapse still occurs in over one-third of cases. Future studies should evaluate strategies to help reduce relapse in patients with ATLL undergoing allo-HCT.
Topics: Allografts; Disease-Free Survival; Female; HTLV-I Infections; Hematopoietic Stem Cell Transplantation; Human T-lymphotropic virus 1; Humans; Incidence; Leukemia-Lymphoma, Adult T-Cell; Male; Randomized Controlled Trials as Topic; Survival Rate; Transplantation Conditioning
PubMed: 31132453
DOI: 10.1016/j.bbmt.2019.05.027 -
The Brazilian Journal of Infectious... 2018Human T-lymphotropic viruses (HTLV) are Deltaretroviruses that infect millions of individuals worldwide via the same transmission routes as HIV. With the aim of exposing... (Review)
Review
Human T-lymphotropic viruses (HTLV) are Deltaretroviruses that infect millions of individuals worldwide via the same transmission routes as HIV. With the aim of exposing the possible re-emergence of HTLV in West Africa since discovery, a systematic review was carried out, focusing on the distribution of the virus types and significance of frequent indeterminate reports, while highlighting the need for mandatory routine blood screening. Capturing relevant data from discovery till date, sources searched were Google Scholar, CrossRef, NCBI (PubMed), MEDLINE, Research Gate, Mendeley, abstracts of Conferences and Proceedings, organization websites and reference lists of selected papers. A total of 2626 references were initially retrieved using search terms: Worldwide prevalence of HTLV, HTLV in Africa, HTLV in West Africa, HTLV subtypes, HTLV 3 and 4 in Africa, HTLV of African origin, HTLV seroindeterminate results, Spread of HTLV. These references were rigorously trimmed down to 76. Although evidence shows that HTLV is still endemic in the region, West Africa lacks recent epidemiological prevalence data. Thorough investigations are needed to ascertain the true cause of indeterminate Western Blot results. It is imperative that routine screening for HTLVs be mandated in West African health care facilities.
Topics: Africa, Western; Deltaretrovirus; Deltaretrovirus Infections; Female; Humans; Male; Prevalence; Risk Factors; Seroepidemiologic Studies
PubMed: 29879426
DOI: 10.1016/j.bjid.2018.05.003 -
Tropical Medicine & International... Mar 2016Human T-lymphotropic virus (HTLV)-1 causes T-cell leukaemia and myelopathy. Together with HTLV-2, it is endemic in some African nations. Seroprevalence data from Malawi... (Meta-Analysis)
Meta-Analysis Review
OBJECTIVES
Human T-lymphotropic virus (HTLV)-1 causes T-cell leukaemia and myelopathy. Together with HTLV-2, it is endemic in some African nations. Seroprevalence data from Malawi are scarce, with no reports on associated disease incidence. HTLV seroprevalence and type were tested in 418 healthy mothers from Malawi. In addition, we tested the sera of 534 children to investigate mother-to-child transmission. To provide context, we conducted a systematic review and meta-analysis of HTLV seroprevalence in African women and children.
METHODS
Stored samples from a previous childhood cancer and BBV study were analysed. ELISA was used for HTLV screening followed by immunoblot for confirmation and typing. Standard methods were used for the systematic review.
RESULTS
HTLV seroprevalence was 2.6% (11/418) in mothers and 2.2% (12/534) in children. Three mothers carried HTLV-1 alone, seven had HTLV-2 and one was dually infected. Three children carried HTLV-1 alone, seven had HTLV-2 and two were dually infected. Only two corresponding mothers of the 12 HTLV-positive children were HTLV positive. The systematic review included 66 studies of women and 13 of children conducted in 25 African countries. Seroprevalence of HTLV-1 varied from 0 to 17% and of HTLV-2 from 0 to 4%.
CONCLUSIONS
In contrast to findings from other studies in Africa, the seroprevalence of HTLV-2 was higher than that of HTLV-1 in Malawi and one of the highest for the African region. The lack of mother-child concordance suggests alternative sources of infection among children. Our data and analyses contribute to HTLV prevalence mapping in Africa.
Topics: Adolescent; Africa; Child; Child, Preschool; Coinfection; Female; HTLV-I Infections; HTLV-II Infections; Human T-lymphotropic virus 1; Human T-lymphotropic virus 2; Humans; Infant; Infectious Disease Transmission, Vertical; Malawi; Male; Pregnancy; Pregnancy Complications, Infectious; Seroepidemiologic Studies
PubMed: 26700941
DOI: 10.1111/tmi.12659 -
International Journal of Infectious... Aug 2014Human T-lymphotropic virus type 1 (HTLV-1) is considered to be the etiological agent of adult T-cell leukemia/lymphoma (ATL) and HTLV-associated myelopathy/tropical... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Human T-lymphotropic virus type 1 (HTLV-1) is considered to be the etiological agent of adult T-cell leukemia/lymphoma (ATL) and HTLV-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Blood transfusion is a common transmission pathway for HTLV-1. However, no surveys to determine the overall prevalence of HTLV-1 infection and HTLV-1 genotypes among blood donors on the Chinese mainland have yet been conducted.
METHODS
A systematic review and meta-analysis of the peer-reviewed literature on this topic was carried out. Data manipulation and statistical analyses were performed using the Comprehensive Meta Analysis Version 2.0 program.
RESULTS
Forty-four eligible articles involving 458525 blood donors were selected. Analysis revealed the pooled prevalences of HTLV-1 infection among blood donors in Fujian and Guangdong provinces to be 9.9/10000 (95% confidence interval (CI) 4.4/10000-22.2/10000) and 2.9/10000 (95% CI 1.7/10000-4.8/10000), respectively; there were only two cases of HTLV-1 infection among 204763 donors in other areas of the Chinese mainland. In addition, 40 of 42 (95.2%) HTLV-1 isolates belonged to the Transcontinental subgroup A of the HTLV-1 subtype A (Cosmopolitan subtype).
CONCLUSIONS
The prevalence of HTLV-1 infection among blood donors is low and restricted mainly to the provinces of Fujian and Guangdong. Most isolates belong to the Transcontinental subgroup within HTLV-1 subtype A.
Topics: Blood Donors; China; Genotype; HTLV-I Infections; Human T-lymphotropic virus 1; Humans; Prevalence
PubMed: 24865322
DOI: 10.1016/j.ijid.2014.02.021