Sexual transmission of human T-cell lymphotropic virus type 1

Molecular and Phylogenetic Evidence of Interfamilial Transmission of HTLV-1 in the Afro-Descendant Community of São José de Icatú in the Brazilian Amazon

This study aimed to describe the prevalence of HTLV-1/2 in quilombola communities in the state of Pará and investigate the possible sociodemographic risk factors associated with the infection, as well as to trace the occurrence of the familial transmission of the virus. A total of 310 individuals living in eight quilombos located in the state of Pará (northern Brazil) were investigated for the presence of anti-HTLV-1/2 antibodies using an enzyme-linked immunosorbent assay (ELISA), and positive samples were confirmed using Western blot and/or real-time quantitative polymerase chain reaction (qPCR). Participants answered a questionnaire about sociodemographic aspects and risk factors for infection. Anti-HTLV-1/2 antibodies were detected in two individuals (one man and one woman), for an overall seroprevalence of 0.65%. Both individuals belonged to the community of São José de Icatú. The search for intrafamilial infection identified two other infected women, which increased the general prevalence of HTLV-1 among the Icatú to 6.25% (4/64). Western blot and qPCR confirmed their HTLV-1 infection, and phylogenetic analysis demonstrated that the isolates were of the cosmopolitan subtype and transcontinental subgroup. Epidemiological investigation of the cases revealed that the three women, at some point in their lives, had a relationship with the infected male individual. HTLV-1 is transmitted silently between individuals in the community of São José de Icatú with a present or past family relationship, stressing the need for screening and laboratory diagnosis to prevent further dissemination of the virus and surveillance of disease emergence.

Prevalence of HTLV-1 and Hepatitis B Surface Antigen (HBsAg) Positivity among MSM Attending a Large HIV Treatment Centre in Trinidad

HIV-1, Hepatitis B and HTLV-1 have similar risk factors and shared routes of transmission and MSM are disproportionately affected by HIV. The aim of the study was to determine the prevalence of HTLV-1 and HBsAg positivity at initial enrolment among MSM attending a large HIV Clinic in Trinidad. Chart reviews were conducted between 2 and 15 January 2024, among self-identified MSM and a comparative group of randomly selected self-identified heterosexual males where sociodemographic, clinical and laboratory data were collected and analysed using SPSS Version 25. During the period April 2002-31 October 2023, in total there were 10,424 patients registered at the clinic, of whom 1255 (12.0%) were self-identified MSM, with an age range of 19-85 years and a median age of 40 years. There were 1822 randomly selected heterosexual males, with an age range of 18-94 years old and a median age of 52 years. Among the MSM, there were 21 (1.67%) patients who were HIV-1/HTLV-1-coinfected, 64 (5.10%) who were HIV-1/HBsAg-coinfected and two (0.16%) who were coinfected with all three viruses (HIV-1/HTLV-1/HBsAg) as compared to 47 ((2.58%) HIV-1/HTLV-1-coinfected (p = 0.12), 69 (3.79%) HIV-1/HBsAg-coinfected (p = 0.10) and three (0.16%) patients coinfected with all three viruses among the heterosexual males. There were no patients with HTLV-1-related diseases among the HIV-1/HTLV-1-coinfected patients and there were no deaths from chronic liver disease in patients coinfected with HIV-1/HBsAg. Despite the availability of an efficacious vaccine, there is a prevalence of hepatitis B of 5.1% among MSM attending the HIV Clinic in Trinidad; therefore, programmes to increase health literacy, screening and immunization are urgently needed.

Onco-Pathogen Mediated Cancer Progression and Associated Signaling Pathways in Cancer Development

Infection with viruses, bacteria, and parasites are thought to be the underlying cause of about 8-17% of the world's cancer burden, i.e., approximately one in every five malignancies globally is caused by an infectious pathogen. Oncogenesis is thought to be aided by eleven major pathogens. It is crucial to identify microorganisms that potentially act as human carcinogens and to understand how exposure to such pathogens occur as well as the following carcinogenic pathways they induce. Gaining knowledge in this field will give important suggestions for effective pathogen-driven cancer care, control, and, ultimately, prevention. This review will mainly focus on the major onco-pathogens and the types of cancer caused by them. It will also discuss the major pathways which, when altered, lead to the progression of these cancers.

How Can We Prevent Mother-to-Child Transmission of HTLV-1?

The perception of human T-cell leukemia virus type 1 (HTlV-1) infection as a "silent disease" has recently given way to concern that its presence may be having a variety of effects. HTLV-1 is known to cause adult T-cell leukemia (ATL), an aggressive cancer of peripheral CD4 T cells; however, it is also responsible for HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Most patients develop ATL as a result of HTLV-1 mother-to-child transmission. The primary route of mother-to-child transmission is through the mother's milk. In the absence of effective drug therapy, total artificial nutrition such as exclusive formula feeding is a reliable means of preventing mother-to-child transmission after birth, except for a small percentage of prenatal infections. A recent study found that the rate of mother-to-child transmission with short-term breastfeeding (within 90 days) did not exceed that of total artificial nutrition. Because these preventive measures are in exchange for the benefits of breastfeeding, clinical applications of antiretroviral drugs and immunotherapy with vaccines and neutralizing antibodies are urgently needed.

The FOXP3-924 A/G Single Nucleotide Polymorphism May Be Associated with Predictive Factors for Human T Lymphotropic Virus 1 Associated Myelopathy

Human T lymphotropic virus 1 (HTLV-1) is a retrovirus associated with inflammatory diseases, including HTLV-1-associated myelopathy (HAM), and host genetic factors may be involved in disease evolution. The forkhead Box P3 (FOXP3) transcription factor is linked to homeostasis of the immune system, and the presence of polymorphisms in the promoter region of the FOXP3 gene should reflect its expression levels and consequent activation of regulatory T cells, which may contribute to severe inflammatory disorders, such as HAM. This study evaluated the rs2232365 polymorphism (-924 A/G) located in the promoter region of the FOXP3 gene and its association with HAM. Forty DNA samples from asymptomatic carriers and 25 samples from HAM patients were used, in addition to 130 control samples. The polymorphism was genotyped by conducting real-time polymerase chain reaction (PCR) (quantitative PCR [qPCR]) on extracted DNA. The proviral loads (PVLs) and CD4⁺ and CD8⁺ T lymphocyte counts were determined by qPCR and FACSCalibur flow cytometry, respectively. The PVLs, CD4⁺ T lymphocyte concentrations, and tumor necrosis factor-α dosages were considered predictive factors of the clinical profiles of HTLV-1 infection, all of which had higher levels in the HAM group. Carriers of the GG genotype for the polymorphism rs2232365 had high PVLs and CD4⁺ T lymphocyte concentrations.

Cost-effectiveness of human T-cell leukemia virus type 1 (HTLV-1) antenatal screening for prevention of mother-to-child transmission

BACKGROUND

Human T-cell leukemia virus type 1 (HTLV-1) causes adult T-cell leukemia-lymphoma (ATL) and HTLV-1-associated myelopathy-tropical spastic paraparesis (HAM/TSP) with a poor prognosis. This study aimed to evaluate the cost-effectiveness and health impact of HTLV-1 antenatal screening.

METHODOLOGY/PRINCIPAL FINDINGS

A state-transition model was developed for HTLV-1 antenatal screening and no screening over a lifetime horizon from a healthcare payer perspective. A hypothetical cohort of 30-year-old individuals was targeted. The main outcomes were costs, quality-adjusted life-years (QALYs), life expectancy life-years (LYs), incremental cost-effectiveness ratios (ICERs), HTLV-1 carriers, ATL cases, HAM/TSP cases, ATL-associated deaths, and HAM/TSP-associated deaths. The willingness-to-pay (WTP) threshold was set at US$50,000 per QALY gained. In the base-case analysis, HTLV-1 antenatal screening (US$76.85, 24.94766 QALYs, 24.94813 LYs, ICER; US$40,100 per QALY gained) was cost-effective compared with no screening (US$2.18, 24.94580 QALYs, 24.94807 LYs). Cost-effectiveness was sensitive to the maternal HTLV-1 seropositivity rate, HTLV-1 transmission rate with long-term breastfeeding from HTLV-1 seropositive mothers to children, and the cost of the HTLV-1 antibody test. HTLV-1 antenatal screening was cost-effective when the maternal HTLV-1 seropositivity rate was greater than 0.0022 and the cost of the HTLV-1 antibody test was lower than US$94.8. Probabilistic sensitivity analysis using a second-order Monte-Carlo simulation showed that HTLV-1 antenatal screening was 81.1% cost-effective at a WTP threshold of US$50,000 per QALY gained. For 10,517,942 individuals born between 2011 and 2021, HTLV-1 antenatal screening costs US$785 million, increases19,586 QALYs and 631 LYs, and prevents 125,421 HTLV-1 carriers, 4,405 ATL cases, 3,035 ATL-associated deaths, 67 HAM/TSP cases, and 60 HAM/TSP-associated deaths, compared with no screening over a lifetime.

CONCLUSION/SIGNIFICANCE

HTLV-1 antenatal screening is cost-effective and has the potential to reduce ATL and HAM/TSP morbidity and mortality in Japan. The findings strongly support the recommendation for HTLV-1 antenatal screening as a national infection control policy in HTLV-1 high-prevalence countries.

Development and Validation of a Rapid Screening Test for HTLV-I IgG Antibodies

Initial diagnosis of human T cell lymphotropic virus (HTLV) infections is mainly based by detecting antibodies in plasma or serum using laboratory-based methods. The aim of this study was to develop and evaluate a rapid screening test for HTLV-I antibodies. Our rapid screening test uses HTLV-I p24 antigen conjugated to gold nanoparticles and an anti-human IgG antibody immobilized to a nitrocellulose strip to detect human HTLV-I p24-specific IgG antibodies via immunochromatography. Performance of the rapid screening test for HTLV-I was conducted on a total of 118 serum specimens collected in Salvador, Bahia, the epicenter for HTLV-1 infection in Brazil. Using a Western blot test as the comparator, 55 serum specimens were HTLV-I positive, 5 were HTLV-I and HTLV-II positive, and 58 were negative. The sensitivity of the rapid screening test for HTLV-1 was 96.7% and the specificity was 100%. The rapid screening test did not show cross-reaction with serum specimens from individuals with potentially interfering infections including those caused by HTLV-II, HIV-I, HIV-II, hepatitis A virus, hepatitis B virus, hepatitis C virus, herpes simplex virus, Epstein-Barr virus, SARS-CoV-2, Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, Toxoplasma gondii, and Plasmodium falciparum. The rapid screening test also did not show cross-reaction with potentially interfering substances. Strategies for HTLV diagnosis in non- and high-endemic areas can be improved with low-cost, rapid screening tests.

HTLV-1 Coinfection among Patients Attending a Large HIV Treatment Centre in Trinidad

Studies have shown that HIV-1/HTLV-1 coinfected patients tend to have higher CD4+ counts than HIV singly infected patients. Two chart reviews were conducted at initial enrolment among patients attending a large HIV Clinic in Trinidad, one to determine the prevalence of HIV-1/HVLV-1 coinfection and another to compare the CD4+ counts and opportunistic infections among HIV-1/HTLV-1 coinfected patients compared to a randomly selected comparison group of HIV-1 singly infected patients. Sociodemographic, clinical and laboratory data were collected and analysed using SPSS Version 25. During the period April 2002−December 2018, 8916 HIV-1 patients were enrolled at the clinic; 159 were HIV-1/HTLV-1 coinfected; the age range was 18−81 years; the median age was 40 years; 87 (54.7%) were females; and the median CD4+ count and median HIV-1 viral load at enrolment were 300 cells/mm3 and 128,543 copies/mL, respectively, with an HTLV-1 seroprevalence of 1.78%. Among the 477 HIV-1 singly infected patients, the age range was 18−71 years; the median age was 33 years; 248 (52.0%) were males; and the median CD4+ count and the median HIV viral load were 295 cells/mm3 and 23,369 copies/mL, respectively. Opportunistic infections (OIs) were diagnosed in 59 (37.1%) of the coinfected patients versus 48 (10.1%) among those HIV singly infected (p < 0.001). HIV-1/HTLV-1 coinfected patients had higher HIV-1 viral loads (p < 0.001) and more OIs, suggesting a worse prognosis though there were no statistically significant differences in CD4+ counts (p = 0.96) as compared to the HIV-1 mono-infected patients.

Prevalence and Risk Factors for HTLV-1/2 Infection inRiverside and Rural Populations of the State of Pará

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) infection has been described in several Amazonian populations; however, there is still a lack of data on the prevalence of the virus in riparian populations living in rural areas of the state of Pará. The present study aimed to evaluate the prevalence of HTLV-1/2 infection in four riverine communities and one rural area in the state of Pará and to describe the possible risk factors for infection. A total of 907 individuals responded to an epidemiological survey and gave blood samples collected for anti-HTLV-1/2 antibodies by immunoenzymatic assay (EIA). The serum-reactive samples were subjected to confirmation by an in-line assay (Inno-Lia) and by proviral DNA screening using real-time PCR (qPCR). The total prevalence was 0.8% (7/907) for HTLV-1/2 (CI: 0.2−1.3%), with 0.66% HTLV-1 and 0.11% HTLV-2. The prevalence by sex was 0.7% in women (4/565) and 0.9% in men (3/342). Among seropositive patients, 83.3% (5/7) reported being sexually active, and 57.1% (4/7) reported not having the habit of using condoms during their sexual relations. Intrafamily infection was also observed. The results reinforce the need for public policies to prevent and block the spread of HTLV, especially in riparian communities that are subject to difficulties in accessing the Unified Health System (Sistema Único de Saúde/SUS) because infected individuals need clinical monitoring for surveillance and early diagnosis of symptoms associated with HTLV-1.

Herpes simplex virus type 2 (HSV-2) and its association with HIV, HCV, HBV, HTLV-1&2 and syphilis among men who have sex with men in Burkina Faso

PURPOSE

This study aimed to estimate herpes simplex virus type 2 (HSV-2) seroprevalence and its association with HIV, HBV, HCV, HTLV-1&2 and syphilis among men who have sex with men (MSM) in Ouagadougou, Burkina Faso, West Africa.

MATERIALS AND METHODS

We screened MSM sera for HSV-2 antibodies. A total of 329 sera were collected from an HIV and syphilis behavioral and biological cross-sectional survey conducted among MSM in Ouagadougou from January to April 2013. Serum samples were tested using Enzyme Linked Immuno-Sorbent Assay (ELISA) for the detection of IgG antibodies to HSV-2. Also, antibodies to HTLV-1&2, HBsAg and anti-HCV antibodies were screened by ELISA. Laboratory assays were performed according to manufacturers' instructions at the Biomedical Research Laboratory at the "Institut de Recherche en Sciences de la Sante" (IRSS) in Burkina Faso.

RESULTS

The seroprevalence of HSV-2 infection among MSM was 14.3%(95% CI: 10.6-18.1), with disparities according to age and occupation. HSV-2 seroprevalence was high among MSM who were seropositive for HIV (40% versus 13.9%), for syphilis (42.9% versus 13.3%), for HCV (32.5% versus 11.7%) and for HTLV-1&2 (38.5% versus 12.9%) compared to people seronegative for these pathogens. Multivariate analysis showed that HIV-positive (ORa ​= ​5.34, p ​= ​0.027), anti-HCV-positive (ORa ​= ​4.44, p ​= ​0.001), and HTLV-1&2 positive (aOR ​= ​4.11, p ​= ​0.046) were associated with HSV-2 infection among MSM. However, no significant statistical association between HSV-2 and syphilis was found.

CONCLUSION

HSV-2 seroprevalence among MSM in Burkina Faso is relatively high. Positive associations between sexual transmitted infections including HIV with HSV-2 suggest that HSV-2 infection's prevention should be strengthened through HIV transmission control programs.

Hijacking Host Immunity by the Human T-Cell Leukemia Virus Type-1: Implications for Therapeutic and Preventive Vaccines

Human T-cell Leukemia virus type-1 (HTLV-1) causes adult T-cell leukemia/lymphoma (ATLL), HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) and other inflammatory diseases. High viral DNA burden (VL) in peripheral blood mononuclear cells is a documented risk factor for ATLL and HAM/TSP, and patients with HAM/TSP have a higher VL in cerebrospinal fluid than in peripheral blood. VL alone is not sufficient to differentiate symptomatic patients from healthy carriers, suggesting the importance of other factors, including host immune response. HTLV-1 infection is life-long; CD4+-infected cells are not eradicated by the immune response because HTLV-1 inhibits the function of dendritic cells, monocytes, Natural Killer cells, and adaptive cytotoxic CD8+ responses. Although the majority of infected CD4+ T-cells adopt a resting phenotype, antigen stimulation may result in bursts of viral expression. The antigen-dependent "on-off" viral expression creates "conditional latency" that when combined with ineffective host responses precludes virus eradication. Epidemiological and clinical data suggest that the continuous attempt of the host immunity to eliminate infected cells results in chronic immune activation that can be further exacerbated by co-morbidities, resulting in the development of severe disease. We review cell and animal model studies that uncovered mechanisms used by HTLV-1 to usurp and/or counteract host immunity.

HTLV-1 and HTLV-2 infections in patients with endemic mycoses in São Paulo, Brazil: A cross-sectional, observational study

Background

Brazil is a country endemic for human T-lymphotropic virus 1 and 2 (HTLV-1 and HTLV-2), systemic mycoses such as paracoccidioidomycosis (PCM) and histoplasmosis (HP), and aspergillosis (AP). The prevalence of HTLV-1/-2 infections in individuals with endemic mycoses in Latin America is unknown; however, an association between HTLV-1 and severe PCM and HP has been observed in Peru. Addressing this knowledge gap, we searched for HTLV-1/-2 antibodies in serum samples sent to the Instituto Adolfo Lutz, São Paulo, Brazil, for systemic mycosis diagnosis.

Methods

We used 387 sera from a biorepository that had seropositive results for Paracoccidioides spp. (G1, n=212), Histoplasma capsulatum (G2, n=95), Aspergillus spp. (G3, n=61), and at least two of these fungi (G4, n=19). We searched for the presence of HTLV-1/-2 antibodies using commercial immunoassays: enzyme immunoassay (HTLV-I+II Murex, Diasorin), western blotting (HTLV Blot 2.4, MP Biomedicals), and line immunoassay (INNO-LIA HTLV I/II, Fujirebio). Demographic characteristics were evaluated in each group.

Findings

Different regions in São Paulo were sampled. Most samples were from males (76.2%; p=0.001), except for G3, in which no sex bias was detected. Mean age differences were observed between groups: patients with PCM and HP had a similar mean age (42.8 and 42.0 years, respectively), while those with AP and co-fungal infection were older (55.1 and 52.8 years, respectively, (p<0.001). Noteworthy, males were older than females in G1 (p=0.005). Screening detected HTLV-1/2 antibodies in five samples (1.30%; 95% CI: 0.8-1.8%), with two borderline results. HTLV-1/2 was confirmed in two samples: 2/387 (0.52%; 0.063-1.85%): one HTLV-2, male, 42 years, from G1: 1/212 (0.47%; 0.012-2.60%), and one HTLV-1, male, 51 years, from G3: 1/61 (1.64%; 0.042-8.80%).

Interpretation

In the state of São Paulo, HTLV-1 and HTLV-2 seem to circulate in male patients with systemic mycoses, and since HTLV-1 could impact fungal disease severity, the identification of co-infection is important regardless of prevalence.

Funding

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES), Fundação de Amparo a Pesquisa do Estado de São Paulo (FAPESP), and Instituto Adolfo Lutz.

The Past, Present, and Future of a Human T-Cell Leukemia Virus Type 1 Vaccine

Human T-cell leukemia virus type 1 (HTLV-1) is an oncogenic human retrovirus which causes a lifelong infection. An estimated 5-10 million persons are infected with HTLV-1 worldwide - a number which is likely higher due to lack of reliable epidemiological data. Most infected individuals remain asymptomatic; however, a portion of HTLV-1-positive individuals will develop an aggressive CD4+ T-cell malignancy called adult T-cell leukemia/lymphoma (ATL), or a progressive neurodegenerative disease known as HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). Few treatment options exist for HAM/TSP outside of palliative care and ATL carries an especially poor prognosis given the heterogeneity of the disease and lack of effective long-term treatments. In addition, the risk of HTLV-1 disease development increases substantially if the virus is acquired early in life. Currently, there is no realistic cure for HTLV-1 infection nor any reliable measure to prevent HTLV-1-mediated disease development. The severity of HTLV-1-associated diseases (ATL, HAM/TSP) and limited treatment options highlights the need for development of a preventative vaccine or new therapeutic interventions. This review will highlight past HTLV-1 vaccine development efforts, the current molecular tools and animal models which might be useful in vaccine development, and the future possibilities of an effective HTLV-1 vaccine.

High Prevalence of HTLV-1 Carriers Among the Elderly Population in Kagoshima, a Highly Endemic Area in Japan

Japan is one of the world's highly endemic areas for human T cell leukemia virus type 1 (HTLV-1), and it is known that the infection rate of HTLV-1 increases with age. The infection rate among the elderly has been estimated based on data from blood donors under the age of 65, and the actual number and rate of infection among the elderly are unknown. Data of 26,090 preoperative HTLV-1 screening tests conducted at Kagoshima University Hospital from 2001 to 2020, including 2726 HTLV-1-positive patients, were used for calculating the decadal infection rates for the year of birth. Estimated infection rates by birth year and demographic tables were used to estimate the current number of infected people in Kagoshima. The estimated total numbers of people infected with HTLV-1 in Kagoshima prefecture were 139,436 in 2005 and 80,975 in 2019. The infection rate increased with age for both men and women, reaching 17.3% for women born before the 1920s. Next, we tried to clarify whether the increase in infection rates with age was due to post-school age infections. The age of birth with the greatest increase in infection rate after 10 years was women born in the 1970s, and the increase in infection rate was only 0.98%, which is not a statistically significant increase. The number of infected people in Kagoshima was >80,000 in 2019. No data were available in this study to point to the involvement of horizontal transmission after school age in the high infection rate among the elderly. The high infection rate among the elderly is thought to have been high even when they were infants.

A Qualitative Study Exploring Perceptions to the Human T Cell Leukaemia Virus Type 1 in Central Australia: Barriers to Preventing Transmission in a Remote Aboriginal Population

Background

Central Australia has the highest recorded prevalence of infection with the human T cell leukaemia virus type 1 (HTLV-1) worldwide. Each of the clinical diseases associated with HTLV-1 have been reported in this region, including deaths due to adult T cell leukaemia, which is causally linked to HTLV-1. Nevertheless, no public health response has been implemented to reduce HTLV-1 transmission among the affected Aboriginal population. In the first study to explore the perceptions of healthcare professionals along with those of Aboriginal people whose communities are actually impacted by HTLV-1, we sought to understand the barriers to preventing HTLV-1 transmission in this remote area.

Methodology/Principal Findings

Semi and un-structured interviews were conducted with 30 Australian Aboriginal people, 26 non-Aboriginal healthcare professionals and 3 non-Aboriginal community workers. The purpose of the interviews was to explore perceptions towards HTLV-1 in a health context with a focus on sexual and reproductive rights. Deductive and inductive analyses were applied to the data and a decolonizing lens brought peripheral stories to the fore. A major finding was the contrast between views expressed by Aboriginal participants and healthcare professionals regarding the provision of knowledge to those affected. Aboriginal participants consistently articulated that they and their communities should be informed of, and can hold, knowledges pertaining to HTLV-1. This finding controverted the perceptions of healthcare professionals that the complexities of the virus would not be well-understood by their Aboriginal patients and that sharing HTLV-1 knowledges might overwhelm Aboriginal people. Further analyses revealed a spectrum of understanding and clinical practice, while also delineating signs of an imagined public health response.

Conclusions/Significance

HTLV-1 remains a neglected infection in Australia. Knowledge of HTLV-1 is held by a privileged medical elite and does not flow to marginalised Aboriginal people living in affected communities. We demonstrate that differences in the perspectives of stakeholders presents a significant barrier to the development of cohesive, culturally safe prevention programs that foster a shared knowledge of HTLV-1. The interview data suggests that a successful public health program is likely to require a dual approach that includes clinical care and community-driven health promotion. Aspects of this approach, which would raise awareness and potentially reduce transmission and lower HTLV-1 prevalence in Central Australia, may be applicable to other endemic settings with similar conditions of social disadvantage, geographic remoteness, resource limitations and cross-cultural challenges.

Current Perspectives in Human T-Cell Leukemia Virus Type 1 Infection and Its Associated Diseases

Human T-cell leukemia virus type 1 (HTLV-1) is a replication-competent human retrovirus associated with two distinct types of diseases: a malignancy of mature CD4⁺ T cells called adult T-cell leukemia-lymphoma (ATL) and a chronic inflammatory central nervous system disease HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). It was the first human retrovirus ever associated with a human cancer. Although most HTLV-1-infected individuals remain asymptomatic for life, a subpopulation develops ATL or HAM/TSP. Although the factors that cause these different manifestations of HTLV-1 infection are not fully understood, accumulating evidence suggests that the complex virus-host interactions, as well as the host immune response against HTLV-1 infection, appear to regulate the development of HTLV-1-associated diseases. This review outlines and discusses the current understanding, ongoing developments, and future perspectives of HTLV-1 research.

Prevalence and Risk Factors for HTLV-1/2 Infection in Quilombo Remnant Communities Living in the Brazilian Amazon

Human T-lymphotropic viruses 1 and 2 (HTLV-1 and HTLV-2) are retroviruses that originated on the African continent and dispersed throughout other continents through human migratory flows. This study describes the prevalence of HTLV-1 and HTLV-2 infection in residents of 11 quilombo remnant communities in the state of Pará, Brazil, and the associated risk factors. A total of 859 individuals (334 men and 525 women), aged between 7 and 91 years, participated in the study. All subjects answered a questionnaire with questions on sociodemographic characteristics and on risk factors associated with HTLV infection, and blood samples were collected and separated into plasma and leukocytes. An immunoenzymatic assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK) was used as a screening test, and positive samples were subjected to line immunoassay confirmatory tests (Inno-LIA HTLV I/II Score FUJIREBIO) and DNA extraction for subsequent real-time PCR to differentiate the viral type. Four of the 859 individuals were seropositive for HTLV. HTLV-1 infection was confirmed in one individual from the Itamoari community (0.92%), and HTLV-2 infection was confirmed in two individuals from São Benedito (3.17%) and in one individual from Arimandeua (2.22%). Blood transfusion was the only risk factor associated with HTLV infection in this study. This study reports the occurrence of HTLV-1 and HTLV-2 in quilombo remnant communities in the state of Pará. Considering the African origin of the virus and its introduction into Brazil from the slave trade, the continued evaluation of quilombola communities in the state of Pará is essential to better characterize the distribution of infections in these populations and to create public health policies for the control of the spread of the virus and associated diseases.

Transcriptional regulators of human oncoviruses: structural and functional implications for anticancer therapy

Transcription is often the first biosynthetic event of viral infection. Viruses produce preferentially viral transcriptional regulators (vTRs) essential for expressing viral genes and regulating essential host cell proteins to enable viral genome replication. As vTRs are unique viral proteins that promote the transcription of viral nucleic acid, vTRs interact with host proteins to suppress detection and immune reactions to viral infection. Thus, vTRs are promising therapeutic targets that are sequentially and structurally distinct from host cell proteins. Here, we review vTRs of three human oncoviruses: HBx of hepatitis B virus, HBZ of human T-lymphotropic virus type 1, and Rta of Epstein-Barr virus. We present three cunningly exciting and dangerous transcription strategies that make viral infections so efficient. We use available structural and functional knowledge to critically examine the potential of vTRs as new antiviral-anticancer therapy targets. For each oncovirus, we describe (i) the strategy of viral genome transcription; (ii) vTRs' structure and binding partners essential for transcription regulation; and (iii) advantages and challenges of vTR targeting in antiviral therapies. We discuss the implications of vTR regulation for oncogenesis and perspectives on developing novel antiviral and anticancer strategies.

Spirituality as Strategies for Coping With Tropical Spastic Paraparesis: Results of Focus Group

In the logic of integrality in health, one of the aspects less addressed by assistance services is the question of spirituality. This study utilized qualitative analysis from focus groups to identify whether spirituality can contribute to coping with problems arising from the HTLV-1 myelopathy associated or tropical spastic paraparesis (HAM/TSP). The testimonies were recorded and then transcribed. The information was then systematized by the analysis of thematic-categorical content. When giving voice to people who suffer from HAM/TSP, there is clear evidence that spirituality, understood broadly and not restricted to institutionalized religious practices, is expressed in narratives of feeling for others and trust in God. Through spiritual solutions, people with HAM/TSP find the strength to face their disability and pain.

Very high prevalence of infection with the human T cell leukaemia virus type 1c in remote Australian Aboriginal communities: Results of a large cross-sectional community survey

Infection with the human T cell leukaemia virus type 1 (HTLV-1) subtype C is endemic among Aboriginal people in central Australia. To provide insights into the risk factors for transmission, we conducted the first large-scale, community-based prevalence study in seven remote Aboriginal communities. Residents >2 years old were invited to participate in the study between August 2014 and June 2018. HTLV-1 infection was defined as a positive western blot (WB) test or a positive HTLV-1 PCR. 720 community residents participated in the study (children <15 years, 142; adults, 578). Prevalences for children and adults were 3.5% (5/142) and 36.8% (213/578), respectively, reaching 49.3% (106/215) for those older than 45 years. A wide range of proviral loads were measured for both asymptomatic and symptomatic participants with no difference within groups according to age or gender; however, median PVL was 1.34 log10 higher for symptomatic participants. The adult prevalence of HTLV-1 infection in central Australia is the highest reported worldwide. Sexual contact is likely to be the predominant mode of transmission.

Blocking HTLV-1/2 silent transmission in Brazil: Current public health policies and proposal for additional strategies

Human T-cell lymphotropic viruses 1 and 2 (HTLV-1/2) are relatively common in Brazil but remain silent and neglected infections. HTLV-1 is associated with a range of diseases with high morbidity and mortality. There is no curative treatment for this lifelong infection, so measures to prevent transmission are essential. This narrative review discusses HTLV-1/2 transmission routes and measures to prevent its continuous dissemination. The public health policies that are currently implemented in Brazil to avoid HTLV-1/2 transmission are addressed, and further strategies are proposed.

HTLV-1 oncovirus-host interactions: From entry to the manifestation of associated diseases

Human T lymphotropic virus type-1 (HTLV-1) is a well-known human oncovirus, associated with two life-threatening diseases, adult T cell leukaemia/lymphoma (ATL) and HTLV-1 associated myelopathy/tropical spastic paraparesis (HAM/TSP). The study of this oncogenic virus is significant from two different aspects. First, HTLV-1 can be considered as a neglected public health problem, which may spread slowly worldwide. Second, the incidence of HTLV-1 associated diseases due to oncogenic effects and deterioration of the immune system towards autoimmune diseases are not fully understood. Furthermore, knowledge about viral routes of transmission is important for considering potential interventions, treatments or vaccines in endemic regions. In this review, novel characteristics of HTLV-1, such as the unusual infectivity of virions through the virological synapse, are discussed in the context of the HTLV-1 associated diseases (ATL and HAM/TSP).

HTLV screening of blood donors using chemiluminescence immunoassay in three major provincial blood centers of China

Background

Human T-cell lymphotropic virus (HTLV) remains a major safety concern for blood supplies. Despite many HTLV positive cases being reported in southeastern China, the detection of HTLV has not been prioritized in routine blood screening. Additionally, data on the prevalence of HTLV infection among blood donors is also limited. The objective of this study was to investigate the prevalence of HTLV among blood donors in three Chinese provinces through their representative blood centers, to evaluate the feasibility of chemiluminescence immunoassay (CLIA) for blood screening.

Methods

From November 2018 to March 2019, blood plasma samples were collected from Hebei, Changsha, and Shenzhen blood centers and were screened for the HTLV-1/2 antibody using a CLIA and enzyme-linked immunosorbent assay (ELISA). This was followed by confirmatory tests using INNO-LIA HTLV I/II.

Results

A total of 59,929 blood donations were collected and screened for HTLV-1/2. The reactive rate of CLIA and ELISA among donations in the Shenzhen blood center (0.0943%, 27/28,621) was higher than Hebei (0.0248%, 4/16,144), and Changsha (0.0198%, 3/15,164) (p < 0.05). After confirmation, 3 samples were confirmed as indeterminate for HTLV antibodies, and only one sample from the Shenzhen blood center was confirmed as HTLV-1. The overall prevalence of HTLV-1/2 was 1.67 per 100,000 (1/59,929). The HTLV-infected blood came from a 32-year-old first-time female donor with a high school degree, who belonged to the SHE ethnic minority and was born in the Fujian province.

Conclusions

In summary, the overall prevalence of HTLV-1/2 among blood donors in the three blood centers in China remains relatively low. However, blood donations with positive or indeterminate results for HTLV antibodies reminded us of the importance of HTLV screening among blood donors in China.

Pooling of sera for human T-cell lymphotropic virus (HTLV) screening in a time of increasing health care expenditure and limited resources

Identifying the true prevalence of human T-cell lymphotropic virus, mostly type 1 (HTLV-1), and the number of patients with HTLV-1-associated diseases, in addition to introducing HTLV-1/2 serology during the prenatal of pregnant women and in individuals infected with other viruses that share transmission routes with HTLV-1, are actions that could help to recognize the importance of this virus by WHO and national health organizations, and to control its transmission/dissemination. As Brazil is endemic to HTLV and there is an increase in health care expenditure, but resources are limited, any strategy that could reduce the cost of HTLV screening is needed and welcomed. This study aimed to determine whether the strategy of pooling sera for HTLV antibody determination is feasible and reduces the costs. Two enzyme immunoassays (EIA Murex HTLV-I+II, Diasorin, UK, and Gold ELISA HTLV-1+2, REM Ind. Com. Ltda., SP, Brazil), and serum samples that resulted in different levels of HTLV-1/2 antibodies by EIA and of which a volume allowed assay validation were employed for analysis. The diagnostic sensitivity and specificity and Cohen's Kappa value, as well as the accuracy and precision were analyzed. After validating the five-sample pool using the EIA Murex (Cohen's Kappa = 1.0), the technique was employed for individual cost comparison in 2,625 serum samples from populations at risk of HTLV infections (HBV, HCV, and HIV-infected individuals). The results from individual and pooled samples confirmed the diagnostic sensitivity (100%) and specificity (100%) of the pooling and a cost minimization varying from 60.7% to 73.6%. In conclusion, the results of this study suggest the use of pooling sera in sero-epidemiological surveillance studies and possibly in prenatal care screening programs in Brazil.

Surveillance of human retroviruses in blood samples from patients with hepatitis B and C in São Paulo, Brazil

INTRODUCTION

Human retroviruses and the hepatitis B and C viruses (HBV and HCV, respectively) share routes of transmission; thus, coinfections occur and could alter subsequent disease outcomes. A preliminary study on human T-lymphotropic virus types 1 and 2 (HTLV-1/2) in serum samples from HBV- and HCV-infected individuals in São Paulo revealed 1.3% and 5.3% rates of coinfection, respectively. These percentages were of concern since they were detected in HTLV-endemic regions and in high-risk individuals in Brazil. The present study was conducted to extend and confirm these data.

METHODS

HTLV-1/2 and human immunodeficiency virus (HIV) infection status were identified in 1,984 sera for HBV and HCV viral load quantification - 1,290 samples from HBV-infected individuals (53.3% men, mean age: 47.1 years) and 694 samples from HCV-infected individuals (56.3% men, mean age: 50.1 years). HTLV-1/2 antibodies were detected by enzyme immunoassay, followed by western blotting and line immunoassay; HIV infection was detected by enzyme immunoassay.

RESULTS

HTLV-1/-2 infection was detected in 1.9% HBV-infected individuals (0.7% HTLV-1 and 1.2% HTLV-2) and in 4.0% (2.4% HTLV-1 and 1.6% HTLV-2) HCV-infected individuals; HIV infection was detected in 9.2% and 14.5%, respectively. Strong associations with HTLV and HIV, male sex, and older age were found in HBV/HTLV and HCV/HTLV-coinfected individuals (p<0.05).

CONCLUSIONS

HTLV-1 and HTLV-2 were confirmed to be prevalent in individuals with HBV and HCV in São Paulo; coinfected individuals deserve further clinical and laboratory investigation.

From Ancient to Emerging Infections: The Odyssey of Viruses in the Male Genital Tract

The male genital tract (MGT) is the target of a number of viral infections that can have deleterious consequences at the individual, offspring, and population levels. These consequences include infertility, cancers of male organs, transmission to the embryo/fetal development abnormalities, and sexual dissemination of major viral pathogens such as human immunodeficiency virus (HIV) and hepatitis B virus. Lately, two emerging viruses, Zika and Ebola, have additionally revealed that the human MGT can constitute a reservoir for viruses cleared from peripheral circulation by the immune system, leading to their sexual transmission by cured men. This represents a concern for future epidemics and further underlines the need for a better understanding of the interplay between viruses and the MGT. We review here how viruses, from ancient viruses that integrated the germline during evolution through old viruses (e.g., papillomaviruses originating from Neanderthals) and more modern sexually transmitted infections (e.g., simian zoonotic HIV) to emerging viruses (e.g., Ebola and Zika) take advantage of genital tract colonization for horizontal dissemination, viral persistence, vertical transmission, and endogenization. The MGT immune responses to viruses and the impact of these infections are discussed. We summarize the latest data regarding the sources of viruses in semen and the complex role of this body fluid in sexual transmission. Finally, we introduce key animal findings that are relevant for our understanding of viral infection and persistence in the human MGT and suggest future research directions.

Molecular detection of human T cell lymphotropic virus type 1 in pregnant women from Maranhão state, Brazil

The human T cell lymphotropic virus (HTLV) has a worldwide distribution. HTLV is endemic in some states in the northeastern region of Brazil. This study investigated the prevalence of HTLV-1/2 in 713 pregnant women attended at the Central Laboratory of Public Health of Maranhão (LACEN-MA) between February 2015 and May 2017. Serological screening was performed by chemiluminescent microparticle immunoassay (CMIA), and reactive sera were subsequently confirmed by Western blot (WB) analysis. Five samples were determined to be HTLV-1/2-reactive by CMIA analysis, while in the WB analysis, three sera were positive for HTLV-1, and two were indeterminate. The polymerase chain reaction (PCR) analysis used to detect HTLV-1 proviral DNA showed a specific 336 base pair fragment for HTLV-1 in all CMIA-reactive serum samples. PCR products were purified and sequenced. We observed a 0.7% molecular prevalence of HTLV-1 infection. The average age of the HTLV-1-positive pregnant women was 25.6 ± 8.2 years, and the average age of the HTLV-1-negative pregnant women was 24.3 ± 6.2 (p = 0.60). We observed that there was no association of HTLV-1 infection with age, ethnicity, marital status, educational level, family income, age of first sexual intercourse, previous pregnancy, breastfeeding, intravenous drug use by partner, history of blood transfusions, or use of condoms. The prevalence of HTLV-1 observed in pregnant women demonstrated the need to implement public health policies for the screening of HTLV-1/2 in prenatal care and counseling to avoid breastfeeding by infected women; this approach could control vertical transmission and reduce the spread of this virus in the population.

Emerging sexually transmitted viral infections: Review of human T-lymphotropic virus-1 disease

Human T-lymphotropic virus-1 is a preventable sexually transmitted infection. In the majority of people it is asymptomatic, remaining undiagnosed and thereby contributing to its silent transmission. When it does manifest it causes significant morbidity and mortality. This review summarises the existing evidence for its role in sexual transmission and offers suggestions for those working in the area of sexual health. This is the third part of a series looking at novel sexually transmitted infections.

Epidemiology and survival trend of adult T-cell leukemia/lymphoma in the United States

BACKGROUND

Globally, 5 million to 10 million people are infected with human T-cell leukemia virus type 1, which causes adult T-cell leukemia/lymphoma (ATLL) in 2% to 5% of the carriers. ATLL is a rare but extremely aggressive malignancy that can be challenging to diagnose. Very little data exist on the incidence patterns of ATLL in the United States.

METHODS

ATLL cases reported to the National Program of Cancer Registries, the Surveillance, Epidemiology, and End Results (SEER) program, and the New York State Cancer Registry were used for the study. Age-adjusted incidence rates were calculated by age, race/ethnicity, sex, and year of diagnosis. The 5-year survival rate was compared among race/ethnicity groups with the SEER data.

RESULTS

During 2001-2015, 2148 ATLL cases were diagnosed in the United States, 18% of which were in New York State. New York State had the highest incidence rate for ATLL, with a rising trend especially among non-Hispanic blacks (NHBs), whereas the incidence was stable across the remainder of the United States. NHBs were diagnosed at a younger median age (54 years) and had a shorter overall survival (6 months). In New York City, only 22.6% of the ATLL cases diagnosed were born in North America.

CONCLUSIONS

This is the largest epidemiological study of ATLL in the United States and shows a rising incidence in New York City. NHBs have a younger age at presentation and poor overall survival. The rising incidence is largely due to NHBs originating from the Caribbean.

Human T-lymphotropic virus 1 and 2 among people who used illicit drugs in the state of Pará, northern Brazil

People who used illicit drugs (PWUDs) represent an important population group for acquisition and viral dispersion. In Brazil, high rates of the human T lymphotropic virus 1 (HTLV-1) and 2 (HTLV-2) have been reported in epidemiological studies. However, the epidemiological scenario of HTLV-1/2 infections in PWUDs is still poorly understood. Thus, this cross-sectional study determined the prevalence, frequency of subtypes and factors associated with HTLV-1/2 infections among PWUDs in the Brazilian state of Pará, an area considered endemic for this virus and with poor health services. Among 826 PWUDs, 53 (6.4%) presented anti-HTLV-1/2 antibodies by EIA and 44 (5.3%) presented proviral DNA by PCR. HTLV-1 and HTLV-2 were detected in 25 (3.0%) and 19 (2.3%) PWUDs, respectively. Subtypes 1a (25/44), transcontinental (23/44) and Japanese subgroups (2/44), 2b (6/44) and 2c (13/44) were identified. Involvement in illicit/criminal activity, daily use of illicit drugs, illicit drug use over 12 years, unprotected sex with other PWUDs, changes in genitalia (including ulcers and wounds), and more than 12 sexual partners were associated with HTLV-1/2 in PWUDs. This high prevalence and intense circulation of subtypes and subgroups of HTLV-1/2 is very worrying, and indicate the need for urgent actions for its control, prevention and treatment.

The first survey of human T-cell lymphotropic viruses (HTLV) in HIV/AIDS patients in Santa Catarina State, Brazil

Santa Catarina is a Brazilian State that has reported the lowest prevalence of human T-cell lymphotropic viruses (HTLV-1/2) in blood donors (0.04%). Although it presents ports, airports and roads that facilitate the entrance and dissemination of new infectious agents, no information exists concerning the HTLV-1/2 infections in HIV/AIDS patients. This study searched for HTLV-1/2 antibodies in plasma samples of 625 HIV/AIDS patients from the municipality of Tubarao (Southern Santa Catarina), and disclosed 1.1% of positivity (0.48% HTLV-1, 0.48% HTLV-2 and 0.16% untypeable HTLV), and a positive correlation with the male sex (OR 4.16) and intravenous drug use (OR 35.18). Although the percentage of 1.1% appears to be low, it is 27.5 times higher than the percentage detected in blood donors. Since HTLV-1 and HTLV-2 are circulating in HIV-infected individuals in Southern Santa Catarina, and these retroviruses could cause a differently impact on the HIV/AIDS outcomes, the surveillance of HTLV-1/2 is necessary, and it could support public health policies in preventing the transmission and dissemination of these viruses in this State.

Prevalence of human T-cell lymphotropic virus and the socio-demographic and risk factors associated with the infection among post-natal clinics women in Zaria, Nigeria

Introduction: Human T-cell lymphotropic virus has long been associated with Adult T-cell leukemia/lymphoma, HTLV-associated myelopathy/tropical spastic paraparesis, and hairy cell leukemia. Aim: The aim was to determine the prevalence of HTLV antibodies as well as the socio-demographic and risk factors associated with HTLV among women attending postnatal clinics in Zaria. Methodology: A total of 190 samples were collected within the months of January and June 2017 and qualitative determination of antibodies for HTLV in serum was performed by an antigen sandwich enzyme immunoassay method. Results: The study established an HTLV infection prevalence of 3.2% (6/190). Higher prevalence was observed among women from polygamous families [6.2% (4/64)], the self-employed [6.5% (4/62)], those in age group of 15-25 years [6.2% (5/72)] and women with only primary education [5.9% (2/32)] although the associations were not statistically significant. Similarly, there was no significant association between HTLV infection and history of family cancer (P = .629), intravenous drug use (P = .682), sharing of sharp objects (P = .596,) and history of X-ray exposure (P = .366), except for history of previous blood transfusion which shows significant association (P = .010). Conclusion: The study established a prevalence an HTLV of 3.2% that HTLV in Zaria therefore routinely screened is necessary.

HTLV prevalence is no longer following the decreasing HIV prevalence - 20 years of retroviral surveillance in Guinea-Bissau, West Africa

BACKGROUND

The HIV-2 and HTLV-1 prevalences in Bissau have followed similar trends in surveys from 1996 and 2006 with HTLV-1 prevalences of 3.6% and 2.3%, respectively. However, following the introduction of antiretroviral treatment (ART) and informative campaigns about HIV, the epidemics may have shifted. To evaluate the current HTLV prevalence and the continued association with HIV, we performed a third survey.

METHODS

A cross-sectional survey was performed from November 2014 to February 2016. In total, 2583 participants were interviewed, tested for HIV, and had blood samples collected. Samples were analysed for anti-HTLV using chemiluminescence and immunoblot assays. We calculated the HTLV prevalence for 2016 and examined risk factors for HTLV and associations with HIV using binominal regression.

RESULTS

The prevalence of HTLV was 2.8% (71/2583), 1.5% (16/1,089) for men and 3.7% (55/1,494) for women. Old age, female sex, HIV-2 infection and sharing a house with a HTLV- infected person were strong risk factors for HTLV. In contrast to previous studies, we found a non-significant increase in prevalence among the 15-24 year-olds since 2006, supporting ongoing transmission.

CONCLUSIONS

The HTLV prevalence in Bissau showed a non-significant increase. We found evidence supporting continuous vertical and horizontal routes of transmissions.

Human T cell leukemia virus type 1 and Zika virus: tale of two reemerging viruses with neuropathological sequelae of public health concern

Human T cell leukemia virus type 1 (HTLV-1) and Zika virus (ZIKV) have been considered neglected viruses of low public health concern until recently when incidences of HTLV-1 and ZIKV were observed to be linked to serious immune-related disease and neurological complications. This review will discuss the epidemiology, genomic evolution, virus-host interactions, virulence factors, neuropathological sequelae, and current perspectives of these reemerging viruses. There are no FDA-approved therapeutics or vaccines against these viruses, and as such, it is important for clinical trials to focus on developing vaccines that can induce cell-mediated immune response to confer long-term protective immunity. Furthermore, attention should be paid to reducing the transmission of these viruses through unprotected sex, infected blood during sharing of contaminated needles, donated blood and organs, and vertical transmission from mother to baby via breastfeeding. There is an urgent need to re-evaluate repurposing current antiviral therapies as well as developing novel antiviral agents with enhanced efficacy due to the high morbidity rate associated with these two reemerging chronic viral diseases.

Hepatitis B, C, and D virus and human T-cell leukemia virus types 1 and 2 infections and correlates among men who have sex with men in Ouagadougou, Burkina Faso

BACKGROUND

Men who have sex with men (MSM) are considered to be at significant risk for sexually transmitted infections (STI) and bloodborne viruses including viral hepatitis types B, C, and D (HBV, HCV, and HDV) and human T-cell leukemia virus types 1 and 2 (HTLV 1&2). This study aimed to assess the seroprevalence and correlates of HBV, HCV, HDV, and HTLV 1&2 antibodies among MSM in Ouagadougou, Burkina Faso.

METHODS

We conducted a cross-sectional survey to assess the biological and behavourial characteristics among MSM in Ouagadougou from January to April 2013. Serum specimens obtained were tested for the presence of HBV, HCV, HDV and HTLV-1&2 infections. MSM 18 years and older were recruited using respondent driven sampling (RDS). Population estimates and 95% confidence intervals (CI) adjusted for the RDS design were calculated using RDS Analysis Tool (RDSAT) version 6.0.1 (RDS, Inc., Ithaca, NY). Bivariate and multivariate logistic regression analyses were conducted to assess correlates of these infections using Stata 14.

RESULTS

A total of 329 MSM were tested. Prevalence was 20.4% (95% CI: 16.4-25.1) for HBV, 11.0% (95% CI: 8.0-14.8) for HCV, and 0.0% for HDV. Anti-HTLV 1&2 antibodies were found in 4.0% (95% CI: 2.3-6.8) of MSM. Factors independently associated with HBV infection were lack of condom use during the last anal sex act with a main male sexual partner and experience of condom tearing during anal sex. Presence of anti-HTLV 1&2 antibodies was associated with history of genital or anal lesions and injection drug use. None of the variables included in our study were associated with HCV.

CONCLUSIONS

This study shows that HBV, HCV and HTLV 1&2 prevalence among MSM in Burkina is high and suggests that comprehensive STI prevention and sexual health education services for this group are needed.

Risk factors associated with HTLV-1 vertical transmission in Brazil: longer breastfeeding, higher maternal proviral load and previous HTLV-1-infected offspring

HTLV-1 is transmitted primarily either through sexual intercourse or from mother to child. The mother/child pairs were classified as seroconcordant or serodiscordant. We analyzed mother to child transmission (MTCT) according to sociodemographic, clinical and epidemiological characteristics of the mother, child's gender and duration of breastfeeding. Between June 2006 and August 2016 we followed 192 mothers with HTLV-1 infection (mean age 41 years old), resulting in 499 exposed offspring, 288 (57.7%) of whom were tested for HTLV-1, making up the final sample for the study, along with their 134 respective mothers. Among the tested mother/child pairs, 41 (14.2%) were HTLV-1 positive, highlighted that seven of 134 family clusters concentrated 48.8% of positive cases. Variables associated with a positive child: breastfeeding duration ≥12 months, maternal PVL ≥100 copies/104 PBMC, mother's age at delivery >26 years old, and HTLV-1 in more than one child of the same mother. In a multiple logistic regression, breastfeeding ≥12 months, higher maternal PVL and ≥2 previous HTLV-1-infected children remained independently associated with the outcome. Thus, high maternal PVL and breastfeeding beyond 12 months were independently associated with MTCT of the HTLV-1 infection. Our results reinforce the need for both prenatal HTLV screening in endemic areas and for advising mothers on breastfeeding.

SHTLV-I/II seroprevalence in blood donors of Hospital Pablo Tobón Uribe Blood Bank during the period 2014-2015

Introducción. El virus linfotrópico humano de células T (HTLV) es un retrovirus del cual se conocen varios tipos, entre ellos el HTLV-I y el HTLV-II, los cuales son de importancia clínica por ser los causantes de diferentes enfermedades, como la leucemia y el linfoma de células T del adulto, la paraparesia espástica tropical y la mielopatía asociada al HTLV.Objetivo. Obtener la prevalencia de las reacciones presuntiva y confirmatoria de los virus HTLV-I y HTLV-II en los donantes del Banco de Sangre del Hospital Pablo Tobón Uribe de Medellín, entre el 2014 y el 2015.Materiales y métodos. La información se obtuvo de la base de datos del Banco de Sangre del Hospital Pablo Tobón Uribe. Se analizaron la edad, el sexo y el lugar de procedencia y de residencia de los donantes, así como la reacción en la prueba de tamización (ELISA) y en la prueba confirmatoria (inmunoblot). Resultados. La población de donantes estudiados incluyó a 6.275 hombres y 8.148 mujeres, para un total de 14.423 donantes reclutados entre el 1° de marzo de 2014 y el 30 de junio de 2015. De ellos, 25 resultaron positivos para HTLV-I o HTLV-II en la prueba de tamización (ELISA). En la prueba confirmatoria (inmunoblot), nueve (36 %) pacientes fueron positivos para el HTLV-I o HTLV-II , y de ellos ocho (32 %) lo fueron para el HTLV-I y uno (4 %) para el HTLV-II; la seroprevalencia global fue de 0,06 % (IC95% 0,10-0,25). Conclusiones. Los hallazgos del estudio concordaron con los de estudios similares en áreas no endémicas del país y con los de los estudios consultados a nivel internacional.

Prevalence of Human T-lymphotropic virus type 1 and 2 among blood donors in Manaus, Amazonas State, Brazil

Introduction:

Human T-lymphotropic virus type 1 and 2 (HTLV-1/2) is endemic in Brazil, but few studies have investigated the seroprevalence of HTLV and its subtypes among blood donors in the capital city Manaus, Amazonas State, Brazil.

Aim:

To estimate the seroprevalence of HTLV-1/2 and to identify circulating subtypes among blood donors in Manaus.

Materials and Methods:

Blood donors (2001-2003) were screened for HTLV-1/2 antibodies by ELISA. Positive results were confirmed and subtyped by Western blot assays. Prevalence rates were calculated and compared with demographic data.

Results:

Among the 87,402 individuals screened, 116 (0.13%) were seropositive for HTLV-1/2. A second sample (76/116) was collected and retested by HTLV-1/2 ELISA, of which only 41/76 were positive. Western blot confirmed HTLV infection in 24/41 retested blood donors [HTLV-1 (n=16), HTLV-2 (n=5) and HTLV-untypable (n=3)].

Discussion:

HTLV-1 and HTLV-2 are prevalent among blood donors in Manaus. However, additional studies are needed to comprehend the epidemiology of HTLV-1/2 in Amazonas not only to understand the pathophysiology of the disease providing adequate medical assistance, but also to reduce or block virus transmission.

Short Communication: Failures in Detecting HTLV-1 and HTLV-2 in Patients Infected with HIV-1

Changes in retrovirus acquisition/transmission behaviors have been reported in Brazil, with a concerning increase in HIV-1-infected individuals aged 15-39 years. In São Paulo, HIV-1/HTLV-1 and HIV-1/HTLV-2 coinfections have been associated with intravenous drug use and failure to detect HTLV-1/2 (human T cell lymphotropic virus types 1 and 2) with immunosuppression and the use of highly active antiretroviral therapy (HAART). Negative results for HTLV serologic [western blotting (WB)] and molecular [real-time PCR pol (qPCR)] confirmatory assays have been reported, whereas the best sensitivity has been found for INNO-LIA (LIA). In this study, we expand our previous data by analyzing a group of young patients (n = 1,383; median age 35.6 years) who recently acquired HIV by sexual contact, the majority of whom were HAART naïve, and comparing the performances of four HTLV confirmatory assays: LIA, WB, qPCR, and PCR-RFLP (tax). We confirmed HTLV infection in 58 (4.2%) blood samples: 29 HTLV-1, 24 HTLV-2, 1 HTLV-1+HTLV-2, and 4 HTLV. LIA, WB, qPCR, and PCR-RFLP sensitivities were 94.8%, 82.8%, 79.2%, and 74.5%, respectively. Associations of HTLV infection with female gender (OR = 2.28, 1.31-4.00) and age >40 years (p < .0001) were detected. The results confirm the low sensitivities of molecular assays and the best performance of LIA in detecting HTLV-1/2 in such patients. We hypothesize that the negative PCR results are due to the presence of defective provirus and/or low proviral load circulating in such patients, with inconclusive WB coinciding with the seroconversion period. Corroborating the associations obtained, repeated exposure is required for HTLV sexual transmission/acquisition, which is more efficient from male to female.

Comparative performances of serologic and molecular assays for detecting human T lymphotropic virus type 1 and type 2 (HTLV-1 and HTLV-2) in patients infected with human immunodeficiency virus type 1 (HIV-1)

The present study evaluated several techniques currently available (commercial kits and in-house assays) for diagnosing human T lymphotropic viruses types 1 and 2 in two groups of patients enrolled at HIV/AIDS specialized care services in São Paulo: Group 1 (G1), n = 1608, 1237 male/371 female, median age 44.3 years old, majority using highly active antiretroviral therapy (HAART); G2, n = 1383, 930 male/453 female, median age of 35.6 years old, majority HAART naïve. Enzyme immunoassays [(EIA) Murex and Gold ELISA] were employed for human T lymphotropic viruses types 1 and 2 screening; Western blotting (WB), INNO-LIA (LIA), real-time PCR pol (qPCR), and nested-PCR-RFLP (tax) were used to confirm infection. Samples were considered human T lymphotropic viruses types 1 and 2 positive when there was reactivity using at least one of the four confirmatory assays. By serological screening, 127/2991 samples were positive or borderline, and human T lymphotropic virus infection was confirmed in 108 samples (three EIA-borderline): 56 human T lymphotropic virus type 1 [G1 (27) + G2 (29)]; 45 human T lymphotropic virus type 2 [G1 (21) + G2 (24)]; one human T lymphotropic virus type 1 + human T lymphotropic virus type 2 (G2); six human T lymphotropic virus [G1 (2) + G2 (4)]. Although there were differences in group characteristics, human T lymphotropic viruses types 1 and 2 prevalence was similar [3.1% (G1) and 4.2% (G2), p = 0.113]. The overall sensitivities of LIA, WB, qPCR, and PCR-RFLP were 97.2%, 82.4%, 68.9%, and 68.4%, respectively, with some differences among groups, likely due to the stage of human T lymphotropic virus infection and/or HAART duration. Indeterminate immunoblotting results were detected in G2, possibly due to the seroconversion period. Negative results in molecular assays could be explained by the use of HAART, the occurrence of defective provirus and/or the low circulating proviral load. In conclusion, when determining the human T lymphotropic virus infection, the findings highlight that there is a need to consider the blood samples with borderline results in screening assays. Of all the tested assays, LIA was the assay of choice for detecting human T lymphotropic virus type 1 and human T lymphotropic virus type 2 in human immunodeficiency virus type 1-infected patients.

Analysis of HTLV-1 proviral load (PVL) and antibody detected with various kinds of tests in Japanese blood donors to understand the relationship between PVL and antibody level and to gain insights toward better antibody testing

Adult T-cell leukemia/lymphoma (ATL) occurs in approximately 5% of individuals infected with human T-cell leukemia virus type 1 (HTLV-1). A high proviral load (PVL; more than four copies per 100 peripheral blood mononuclear cells (PBMCs) or 1.6 copies per 100 blood leukocytes) and being male are risk factors for ATL development. Whether anti-HTLV-1 antibody level is related to such risk is unknown. Here, PVL and antibody levels were examined using real-time PCR and other tests in 600 HTLV-1 positive screened Japanese blood donors to understand the relationship between PVL and antibody level in asymptomatic carriers and to gain insights toward better antibody testing for HTLV-1 infection. The 430 donors in whom proviral DNA was detected were considered as true positives for HTLV-1 infection. Among donors aged 40 years or older, more males than females had a PVL corresponding to more than 1.6% infected leukocytes, and an antibody titer below the median (P = 0.0018). In antibody tests using an HTLV-1 positive cell line or Env antigens there was a large discrepancy in antibody titer among 13 provirus-positive samples, probably suggesting that antibody-based screening tests should incorporate multiple HTLV-1 antigens, such as Gag and Env antigens.

HTLV-1 is predominantly sexually transmitted in Salvador, the city with the highest HTLV-1 prevalence in Brazil

Background

Salvador is the city with the highest number of HTLV-1 infected individuals in Brazil, yet the main route of HTLV-1 transmission is unknown.

Objective

To investigate the association of syphilis infection as a proxy for sexual transmission of HTLV-1 infection in the general population of this city.

Methods

A cross sectional population-based study was conducted with 3,451 serum samples obtained by a representative simple random sampling. Data on gender, age, income, and years of education were collected by questionnaire and the presence of HTLV, HIV and Treponema pallidum infection was determined by serology. Logistic regression analysis was used to evaluate the independent effect of the potential explanatory variables to HTLV-1 infection and Odds Ratios (OR) and 95% CI were calculated.

Results

The majority of studied individuals were female (56.4%), had less than 7 years of education (55.3%) and earned two or less minimum wages (52.0%). The overall prevalence of HTLV-1 was 1.48% (51/3,451; 95% CI: 1.10%– 1.94%), which increased with age. Only three persons younger than 17 (3/958; 0.31%; CI 95% 0.06–0.91) years were infected by HTLV-1. Among the 45 syphilis positives, 12 (26.7%) were HTLV positive, while among 21 HIV positives, only one (4.8%) was HTLV positive. HTLV-1 infection was found to be associated with syphilis infection (OR_ADJUSTED 36.77; 95% CI 14.96–90.41).

Conclusion

The data presented herein indicate that horizontal transmission between adults is the main route of HTLV-1 infection in the general population of Salvador and that this is likely to occur through sexual contact.

High risk of heterosexual transmission of human T-cell lymphotropic virus type 1 infection in Brazil

Human T-cell lymphotropic virus type 1 is transmitted primarily either through sexual intercourse or from mother to child. The current study investigated sexual transmission and compared the HTLV-1 proviral load between seroconcordant and serodiscordant couples by examining both men and women among the index partners without using subjective criteria to establish the direction of sexual transmission. Between January 2013 and May 2015, 178 HTLV-1-positive patients had spouses, 107 of which had tested partners, thus increasing the initial sample size (46 men and 61 women). Individuals co-infected with HTLV-2 or human immunodeficiency virus were not included in the analysis. From among the included participants, 26 men and 26 women were paired with each other, resulting in 26 seroconcordant couples; 12 seroconcordant couples were formed from another four men and eight women. Forty-three serodiscordant couples were formed from 16 men and 27 women. The rate of seroconcordance was 46.9%. The HTLV-1 proviral load was compared between 19 and 37 seroconcordant and serodiscondant couples, respectively, and the concordant couples showed higher proviral loads (P = 0.03). There were no differences between the groups according to age, relationship length, having a mother or sibling with HTLV-1, race, ethnicity, nationality, education, history of blood transfusion, HAM/TSP, ALT, or hepatitis C virus status. In multivariate analysis, relationship time was shown associated with ocurrence of seroconcordance status. The apparent association between high circulating levels of provirus and seroconcordance rate among couples suggests that proviral loads contribute markedly to the risk of sexual transmission, regardless of gender index.

Molecular Mechanisms of HTLV-1 Cell-to-Cell Transmission

The tumorvirus human T-cell lymphotropic virus type 1 (HTLV-1), a member of the delta-retrovirus family, is transmitted via cell-containing body fluids such as blood products, semen, and breast milk. In vivo, HTLV-1 preferentially infects CD4⁺ T-cells, and to a lesser extent, CD8⁺ T-cells, dendritic cells, and monocytes. Efficient infection of CD4⁺ T-cells requires cell-cell contacts while cell-free virus transmission is inefficient. Two types of cell-cell contacts have been described to be critical for HTLV-1 transmission, tight junctions and cellular conduits. Further, two non-exclusive mechanisms of virus transmission at cell-cell contacts have been proposed: (1) polarized budding of HTLV-1 into synaptic clefts; and (2) cell surface transfer of viral biofilms at virological synapses. In contrast to CD4⁺ T-cells, dendritic cells can be infected cell-free and, to a greater extent, via viral biofilms in vitro. Cell-to-cell transmission of HTLV-1 requires a coordinated action of steps in the virus infectious cycle with events in the cell-cell adhesion process; therefore, virus propagation from cell-to-cell depends on specific interactions between cellular and viral proteins. Here, we review the molecular mechanisms of HTLV-1 transmission with a focus on the HTLV-1-encoded proteins Tax and p8, their impact on host cell factors mediating cell-cell contacts, cytoskeletal remodeling, and thus, virus propagation.