Performance of immunological assays for universal and differential diagnosis of HTLV-1/2 infection in candidates for blood donations from the Brazilian Amazon.

The present study compares the ability of distinct immunological assays (chemiluminescence immunoassay-CLIA, western blot-WB and flow cytometry-FC-Simplex and Duplex) to detect anti-HTLV (human T-lymphotropic virus) antibodies in candidates for blood donations at the Amazonas State Blood Center (Brazil) between January 2018 and December 2022. Overall, 257,942 samples from candidates for blood donations were screened using CLIA, which led to 0.15% seropositivity for HTLV (409 samples). A total of 151 candidates for blood donations were enrolled for retesting with CLIA followed by additional testing using WB and FC-Simplex and Duplex analysis. Our results demonstrated that 62% (93/151), 20% (30/151) and 17% (26/151) of the samples presented positive results with retesting using CLIA, WB and FC-Simplex analysis, respectively. Additional analysis of the CLIA, WB and FC-Simplex results revealed an overall agreement of 56% for CLIA and WB (22 co-negative; 30 co-positive samples), 48% for CLIA and FC-Simplex (21 co-negative; 24 co-positive samples) and 80% for WB and FC-Simplex (51 co-negative; 23 co-positive samples). Considering the WB as the reference standard for the diagnosis of infection with HTLV-1/2, we observed that the CLIA results of ≤3.0 RLU and >10.0 RLU in the retest can be used define a negative or positive result, respectively, and could be used as new specific cut-off values. The overall agreement between WB and FC-Duplex for accomplishing the differential diagnosis was evaluated and demonstrated 100% correspondence for the diagnosis of HTLV-1 (15/15) and HTLV-2 (7/7). Our findings demonstrate that gaps in the diagnosis of infection with HTLV-1/2 could be overcome by the simultaneous use of distinct immunological assays during retesting of candidates for blood donations.

Human T-lymphotropic virus 1/2 infection among prisoners of a major penitentiary complex of Goiás State, Central-West Brazil.

Introduction: Studies on human T-lymphotropic virus 1/2 (HTLV-1/2) infection are scarce in incarcerated population. Therefore, this study estimated the prevalence of HTLV-1/2 infection among prisoners of the major penitentiary complex of Goiás State, Central-West Brazil, comparing it with available data from other Brazilian regions. Methods: A cross-sectional study was conducted with 910 prisoners of the major penitentiary complex in the State of Goiás, Central-West Brazil. All participants were interviewed, and their serum samples were tested for anti-HTLV-1/2 using an enzyme-linked immunosorbent assay (ELISA; Murex HTLV-I + II, DiaSorin, Dartford, UK). Seropositive samples were submitted for confirmation by a line immunoassay (INNO-LIA HTLV I/II, Fujirebio, Europe N.V., Belgium). Results: The majority of participants were males (83.1%), between 25 and 39 years old (56.1%; mean age: 31.98 years), self-reported brown ethnicity (56.2%) and reported 9 years or less of formal education (41.4%). Most reported using non-injectable illicit drugs and various sexual behaviors that present risk for sexually transmitted infections (STIs). The prevalence of anti-HTLV-1/2 was 0.33% (95% CI: 0.07-0.96), HTLV-1 (0.22%) and HTLV-2 (0.11%). The two HTLV-1 seropositive prisoners reported high-risk sexual behaviors, and the HTLV-2 seropositive individual was breastfed during childhood (> 6 months) by her mother and three other women. Conclusion: These data revealed a relatively low seroprevalence of HTLV-1/2 in prisoners in Central-West Brazil, and evidence of HTLV-1 and HTLV-2 circulation in the major penitentiary complex of Goiás State. Given the prevalence of high-risk sexual behaviors, there is a crucial need to intensify education and health programs in prisons to effectively control and prevent HTLV-1/2 and other STIs.

Prevalence of HTLV-1/2 infection in pregnant women in Central and South America and the Caribbean: a systematic review and meta-analysis.

BACKGROUND: Human T-lymphotropic viruses (HTLV)-1 infection is endemic in many countries of Central and South America and Caribbean (CSA&C). Neither screening nor surveillance programs exist for HTLV-1/2 infection among pregnant women in this region. Neither in Western nations with large migrant flows from HTLV-1/2 endemic regions. METHODS: Systematic review and meta-analysis of the prevalence of HTLV-1/2 infection among CSA&C pregnant women. We included studies searching EMBASE, PubMed/MEDLINE, Scopus, and Web of Science from inception to February 15, 2023. This systematic review followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses reporting guidelines. RESULTS: We identified a total of 620 studies. Only 41 were finally included in the meta-analysis. Most studies (61.0%) were from Brazil and Peru (14.6%). The total number of participants was 343,707. The pooled prevalence of HTLV-1/2 infection among CSA&C pregnant women was 1.30% (95% CI: 0.96-1.69) using anti-HTLV-1/2 antibody screening tests. There was a high heterogeneity (I2 = 98.6%). Confirmatory tests gave an HTLV-1 infection rate of 1.02% (95% CI: 0.75-1.33). CONCLUSIONS: The prevalence of HTLV-1/2 infection among CSA&C pregnant women is 1.3%, most cases being HTLV-1. This rate is greater than for other microbial agents regularly checked as part of antenatal screening (such as HIV, hepatitis B, or syphilis). Thus, HTLV-1/2 antenatal testing should be mandatory among CSA&C pregnant women everywhere.

High Ratio of Human T Cell Lymphotropic Virus Transmission and Prevalence of Human T Cell Lymphotropic Virus Type 1-Associated Diseases in Brazilian Family Groups Followed Up by the GIPH Cohort.

A silent spread of human T cell lymphotropic virus type 1 (HTLV-1) has been occurring for thousands of years, with a high prevalence in some regions due to the sexual and vertical transmission and formation of family clusters. The time from HTLV-1 infection until the onset of virus-associated diseases is extremely long, approximately one to three decades. In this study, we evaluated intrafamilial HTLV-1 transmission and associated diseases in 1,204 individuals enrolled and followed up by the GIPH cohort between 1997 and 2017. The family groups (n = 43) were composed of 279 individuals who were tested for HTLV-1/human T cell lymphotropic virus type 2 (HTLV-2) and were classified as two groups according to the index case: blood donor (blood donors referred to the GIPH cohort) and nondonor (individuals referred to the GIPH cohort by other health services). The observed rates of HTLV-1 transmission and associated diseases among the relatives were high. Of 236 family members and sexual partners tested for HTLV, 104 (44.1%) were confirmed as having HTLV infection, with 36.7% of relatives whose index case was blood donors and 56.9% of relatives with nondonor index cases. At least one case of HTLV-1-associated myelopathy was observed in 42.9% of the families with intrafamilial transmission of HTLV-1. Brazil is an endemic area for HTLV-1/2 and has implemented mandatory universal screening of blood donors for HTLV-1/2 since 1993. However, the lack of public health services offer diagnosis for HTLV to the general population and pregnant women in the country makes it difficult to identify infected people, and contributes to the silent spread of the virus.

Evaluation of the New Multi-HTLV Serological Assay: Improvement for HTLV-2 Detection.

Despite the accuracy of confirmatory tests for the diagnosis of human T cell lymphotropic virus (HTLV), inconclusive or false-negative results still occur when diagnosing human T cell lymphotropic virus type 2 (HTLV-2)-positive patients. The goal of this study was to evaluate the sensitivity and accuracy of a confirmatory immunoassay, the Multi-HTLV assay. A total of 246 plasma samples were tested by real-time polymerase chain reaction (qPCR) and used to calculate the sensitivity and typing accuracy of the Multi-HTLV assay. Of the 246 plasma samples, 127 were positive for human T cell lymphotropic virus type 1 (HTLV-1), 112 were positive for HTLV-2, and 7 were positive for both HTLV-1 and HTLV-2. Thereafter, the nonparametric Mann-Whitney U test was used to calculate the concordance between the qPCR test and Multi-HTLV assay in 12 samples with discrepant and inconclusive qPCR results. The Multi-HTLV assay showed high performance in identifying HTLV-1 and HTLV-2 with sensitivities of 97% [95% confidence interval (CI): 0.92-0.98] and 94% (0.87-0.96), respectively. However, due to typing performance (98% for HTLV-1 and 94% for HTLV-2), it had 95% agreement with positive HTLV-1 qPCR results (95% CI: 90.07-97.81) and 86% (78.04-91.01) of HTLV-2 qPCR results were positive. Moreover, this test was able to recognize 80% of indeterminate samples and all HTLV-2 positive samples that showed false-negative qPCR results. Our findings, derived from a substantial number of HTLV-positive samples, underscore the inherent reliability and feasibility of the Multi-HTLV assay, regardless of the molecular testing facilities. Furthermore, the distinctive multiparametric nature of this assay, combined with its straightforward procedural execution, introduces novel perspectives for analyzing specific serological profiles in each patient, as well as the potential for immunological monitoring of disease progression.

Distribución geográfica y tipo de infección del virus linfotrópico T humano en pacientes peruanos 2019-2021 / Geographic distribution and type of human T-lymphotropic virus (HTLV) infection in Peruvian patients 2019-2021

En el presente estudio describimos y caracterizamos la distribución geográfica de los casos positivos confirmados a HTLV-1 y 2 de pacientes peruanos con diagnóstico presuntivo entre 2019 y 2021. De un total de 555 muestras positivas confirmadas, 546 (98,4%) fueron HTLV-1 y 9 (1,6%) HTLV-2. Además, 22 de 24 departamentos del Perú presentaron casos de HTLV-1, siendo los principales motivos de solicitud de confirmación diagnóstica: aspirante a donar sangre con prueba de tamizaje reactivo, sospecha de leucemia/linfoma y paraparesia espástica tropical. Los resultados reflejan que la identificación de los puntos críticos constituye una brecha persistente respecto al diagnóstico, siendo cruciales para reducir el número de nuevos casos en Perú.

In the present study we describe and characterize the geographic distribution of HTLV-1 and 2 positive cases from Peruvian patients with presumptive diagnosis 2019 - 2021. Of a total of 555 confirmed positive samples, 546 (98.4%) were HTLV-1 and 9 (1.6%) HTLV-2. In addition, 22 of 24 departments of Peru presented cases of HTLV-1. The main reasons for requesting a confirmatory diagnosis being: aspiring to donate blood with a reactive screening test, suspicion of leukemia/ lymphoma and tropical spastic paraparesis. The results reflect that the identification of critical points constitutes a persistent gap regarding the diagnosis, being crucial to reduce the number of new cases in Peru.

Fórum internacional sobre políticas de saúde para a eliminação do HTLV: Promoção de políticas de saúde para o HTLV em todo o mundo. Relatório da reunião, 10 de novembro de 2021

A infecção pelo vírus linfotrópico de células T humanas (HTLV) afeta principalmente grupos populacionais vulneráveis: pessoas vivendo em situação de pobreza em áreas com índices de desenvolvimento humano muito baixos, profissionais do sexo, homens que fazem sexo com homens, pessoas que injetam drogas e grupos populacionais epidemiologicamente fechados e semifechados, incluindo populações tradicionais e indígenas. Esse vírus e suas consequências foram negligenciados por décadas, apesar da alta morbidade e mortalidade atribuíveis à infecção pelo HTLV. As políticas públicas de saúde para o HTLV-1/2 são consideradas escassas na região das Américas e geralmente se limitam à triagem de doadores de sangue. A expansão da testagem para HTLV-1/2 deve ser priorizado, e o aconselhamento das pessoas que vivem com HTLV é uma oportunidade para evitar a transmissão. A testagem de gestantes, seguido de interrupção ou limitação da amamentação, deve ser uma prioridade, e testes direcionados para aqueles grupos de populações com alto risco de infecção deve ser considerados. A falta de conscientização sobre a HTLV é um grande desafio, e o engajamento da OPAS/OMS é crucial para superar esse obstáculo. A inclusão do HTLV em programas existentes, como IST e saúde materna, e programas focados na eliminação de doenças infecciosas e infecções negligenciadas, foi identificada como uma oportunidade para facilitar a implementação de políticas de saúde relativas ao HTLV-1/2 na Região. O investimento em pesquisa é necessário para fechar lacunas no conhecimento e desenvolver políticas e ferramentas econômicas que apoiem o avanço de respostas bem-sucedidas em saúde pública, como testes de ponto de cuidado de baixo custo para o diagnóstico HTLV-1/2. A infecção por HTLV também tem impacto negativo nos desfechos de coinfecções comuns na Região, incluindo tuberculose, strongyloidiasis, ISTs e micose. Aspectos genéticos, ambientais e socioculturais podem influenciar os desfechos de agrupamento ou doenças do HTLV-1 na Região. A agregação familiar também é importante e deve ser considerada ao avaliar o impacto das infecções pelo HTLV-1 e projetar políticas de combate a esse vírus. HTLV-2 é o tipo de vírus predominante entre populações indígenas nas américas. Políticas bem-sucedidas para controlar essa infecção devem contar com uma abordagem combinada para superar barreiras linguísticas, culturais e geográficas. Este relatório destaca algumas das principais intervenções disponíveis para a prevenção e controle da infecção pelo vírus linfotrópico de células T humanas (HTLV) e suas consequências e resume experiências nacionais e institucionais, discussões, sucessos e desafios associados à implementação de políticas públicas de saúde para a eliminação da infecção pelo HTLV. Esses temas foram apresentados no webinar "HTLV World Day 2021: Fórum Internacional de Política de Saúde para a eliminação do HTLV – Avanço das políticas de saúde HTLV em todo o mundo".

HTLV infection in Brazil's second-largest indigenous reserve.

Human T-lymphotropic viruses 1 and 2 (HTLV-1/2) have a worldwide distribution. HTLV-1 has been associated with several diseases, including an aggressive malignant disease known as adult T-cell leukemia/lymphoma and a chronic inflammatory neurological disease called HTLV-1-associated myelopathy, while HTLV-2 has not been definitively associated with diseases. HTLV-2 is most prevalent in specific groups such as injecting drug users and the indigenous population. In Brazil, most studies about HTLV in indigenous are carried out in indigenous communities from the north of the country. Mato Grosso do Sul (MS), Central Brazil, has the second-largest indigenous population in Brazil. However, there is no available data about HTLV infection in this group. We conducted the first investigation of HTLV-1/2 infection prevalence in the indigenous population from Jaguapiru and Bororó villages in Dourados City, MS, to provide the prevalence and molecular characterization of HTLV. For that, a total of 1875 indigenous participated in the study. All the serum samples were screened by an enzyme-linked immunosorbent assay commercial kit for the presence of anti-HTLV-1/2 antibodies. Positive samples were confirmed by HTLV-1/2 Western Blot assay. The HTLV-1 5'LTR region was detected by nested PCR amplification and sequenced by Sanger. Most of the study population declared belonging to Guarani-Kaiowá ethnicity (69.18%), 872 (46.51%), and 1003 (53.49%) were from Jaguapiru and Bororó villages, respectively. The median age of participants was 31 years, and 74.24% were females. Two individuals were detected with HTLV-1 (0.1%; CI 95% 0.1-0.2). The phylogenetic analysis revealed that isolates belong to the Cosmopolitan subtype and the Transcontinental subgroup (HTLV-1aA). The low HTLV-1 prevalence found in this study is similar to that observed among blood donors, and pregnant populations from Mato Grosso do Sul. The absence of HTLV-2 infection among these Brazilian indigenous communities would suggest a distinct behavior pattern from other indigenous populations in Brazil.

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.

Foro internacional de políticas de salud para la eliminación del HTLV: Promoción de políticas de salud sobre el HTLV en todo el mundo. Informe de reunión, 10 de noviembre del 2021

La infección por el virus linfotrópico humano de células T (HTLV, por su sigla en inglés) afecta principalmente a los grupos de población vulnerables, a saber, las personas que viven en la pobreza en zonas donde el índice de desarrollo humano es muy bajo, los trabajadores sexuales, los hombres que tienen relaciones sexuales con hombres, los consumidores de drogas inyectables y los grupos de población cerrados y semicerrados desde el punto de vista epidemiológico, incluidos los grupos tradicionales e indígenas. El HTLV y sus consecuencias han sido desatendidos durante decenios, a pesar de la elevada carga de morbilidad y mortalidad causada por la infección por este virus. Hay pocas políticas de salud pública sobre el HTLV de tipo 1 y el HTLV de tipo 2 en la Región de las Américas y generalmente se limitan al tamizaje de los donantes de sangre. Se debe priorizar la ampliación de las pruebas del HTLV-1/2, así como el asesoramiento de las personas con infección por el HTLV‑1, que ofrece la posibilidad de prevenir la transmisión. Otra prioridad es realizar pruebas a las embarazadas y evitar o limitar la lactancia materna, y también deben sopesarse las ventajas y desventajas de realizar pruebas a las personas con alto riesgo de infección. Dado que la falta de conciencia sobre el HTLV plantea un desafío importante, la intervención de la OPS es decisiva para superar este obstáculo. Se determinó que la inclusión de la infección por el HTLV en los programas vigentes, como los de prevención y control de las ITS, salud materna y eliminación de las enfermedades infecciosas y las infecciones desatendidas, ofrece la posibilidad de agilizar la ejecución de políticas de salud sobre el HTLV 1 y 2 en la Región. Es necesario invertir en investigación encaminada a subsanar las lagunas en el conocimiento y formular políticas e instrumentos costoeficaces que apoyen el fomento de respuestas de salud pública eficaces, como las pruebas de bajo costo en el lugar de consulta para diagnosticar la infección por el HTLV-1/2. La infeccion por el HTLV-1 también tiene efectos negativos en los desenlaces clínicos de coinfecciones frecuentes en la Región, incluidas la tuberculosis, la estrongiloidiasis, las ITS y las micosis. Es posible que los aspectos genéticos, ambientales y socioculturales influyan en los conglomerados de casos de infección por el HTLV-1 o en los desenlaces de la enfermedad en la Región. La agregación familiar también es importante y debe tenerse en cuenta al evaluarse las consecuencias de la infección por el HTLV-1 y formularse las políticas contra este virus. El virus linfotrópico humano de células T de tipo 2 (HTLV-2) es el que predomina entre los indígenas de la Región de las Américas. Las políticas eficaces para controlar esta infección deben basarse en una estrategia combinada que permita superar los obstáculos lingüísticos, culturales y geográficos. En este informe se destacan algunas de las principales intervenciones disponibles para la prevención y el control de la infección por el virus linfotrópico humano de células T (HTLV, por su sigla en inglés) y sus consecuencias. También se resumen las experiencias, los debates, los logros y los desafíos a nivel nacional e institucional en relación con la ejecución de políticas de salud pública orientadas a eliminar esta infección. Estos temas se presentaron en el seminario web “Día Mundial de Lucha contra el HTLV 2021: Foro internacional de políticas de salud para la eliminación del HTLV. Promoción de las políticas de salud sobre el HTLV en todo el mundo”.

Reflection About the Ancient Emergence of HTLV-2 Infection.

During millions of years, viruses have emerged and reemerged, with imbalance of photogenicity and transmissivity overtime. This letter describes that sometimes the nomenclature is uncertain what may actually happen during retrovirus evolution nowadays. This article discusses a possibility that human T-lymphotropic virus type 2 (HTLV-2) has been processed to incorporate the human genome in the last millions of years. Persistent viruses such as human immunodeficiency virus type 1 (HIV-1), HIV-2, and human T cell lymphotropic type 2 may also have potential of endogenization instead of a cytolytic process in a long time.

Decline in human T-cell lymphotropic virus seroprevalence in blood donors from Minas Gerais, Brazil over a 12-year period (2006-2017).

To investigate a 12-year historical series (2006-2017) of human T-cell lymphotropic virus (HTLV)-positive blood donations from Fundação Hemominas, Minas Gerais, Brazil, an observational retrospective study was performed to evaluate data of blood donor candidates who were screened for HTLV-1/2 by enzyme-linked immunosorbent assay or chemiluminescence assays and confirmed by Western blot. We analyzed 3 309 716 blood donations covering 2006-2017 that were extracted from the institutional database. In a total of 3 308 738 donations that have complete algorithm tests, the global frequency of HTLV-positive donations was 0.012%. The seroprevalence in first-time blood donors was 28.82/100 000 donors; 0.95/100 000 donations were HTLV-positive in repeat blood donors. The frequency of HTLV-seropositive females was significantly higher than males (odds ratio = 1.85, p < 0.001) in first-time donors. The median age of HTLV-positive first-time and repeat donors was similar (36 and 32 years, respectively). First-time donors ≥41 years had higher odds to be infected. There was a clear tendency of decline in the HTLV-positive donations in the period analyzed, going from 19.26/100 000 donations to 8.50/100 000 donations. The increase in the proportion of repeat donors over the period analyzed (from 23% in 2006 to 67% in 2017) must be the principal factor that contributed to this drop. Our results showed a continuous decline in the frequency of HTLV-positive donations from Minas Gerais, Brazil throughout 12 years and emphasize the importance of having a high rate of repeat donors in blood centers to reduce the residual risk of transfusion-transmitted infections.

Multi-Epitope Protein as a Tool of Serological Diagnostic Development for HTLV-1 and HTLV-2 Infections.

A multi-epitope protein expressed in a prokaryotic system, including epitopes of Env, Gag, and Tax proteins of both HTLV-1 and HTLV-2 was characterized for HTLV-1/2 serological screening. This tool can contribute to support the implementation of public policies to reduce HTLV-1/2 transmission in Brazil, the country with the highest absolute numbers of HTLV-1/2 infected individuals. The chimeric protein was tested in EIA using serum/plasma of HTLV-infected individuals and non-infected ones from four Brazilian states, including the North and Northeast regions (that present high prevalence of HTLV-1/2) and Southeast region (that presents intermediate prevalence rates) depicting different epidemiological context of HTLV-1/2 infection in our country. We enrolled samples from Pará (n = 114), Maranhão (n = 153), Minas Gerais (n = 225) and São Paulo (n = 59) states; they are from blood donors' candidates (Pará and Minas Gerais), pregnant women (Maranhão) and HIV+/high risk for sexually transmitted infection (STI; São Paulo). Among the HTLV-1/2 positive sera, there were co-infections with viral (HTLV-1 + HTLV-2, HIV, HCV, and HBV), bacterial (Treponema pallidum) and parasitic (Trypanosoma cruzi, Schistosma mansoni, Strongyloides stercoralis, Entamoeba coli, E. histolytica, and Endolimax nana) pathogens related to HTLV-1/2 co-morbidities that can contribute to inconclusive diagnostic results. Sera positive for HIV were included among the HTLV-1/2 negative samples. Considering both HTLV-1 and HTLV-2-infected samples from all states and different groups (blood donor candidates, pregnant women, and individuals with high risk for STI), mono or co-infected and HTLV-/HIV+, the test specificity ranged from 90.09 to 95.19% and the sensitivity from 82.41 to 92.36% with high accuracy (ROC AUC = 0.9552). This multi-epitope protein showed great potential to be used in serological screening of HTLV-1 and HTLV-2 in different platforms, even taking into account the great regional variation and different profile of HTLV-1 and HTLV-2 mono or co-infected individuals.

Development of a nested real time PCR/high resolution melting assay for human T-cell lymphotropic viruses types 1 and 2 (HTLV-1 and 2) identification.

HTLV-1 and HTLV-2 are present in different high-risk populations, such as sexual workers and injecting drug users (IDUs). HTLV-1 is endemic in areas of Middle East, Southern Japan and Latin America, whereas HTLV-2 infection is endemic among some Native Americans and some Central African tribes. The pathogenic consequences and clinical manifestations of these two viruses differ significantly, demanding an adequate identification; therefore, proper diagnosis of HTLV-1 and 2 infection is crucial. To get a final diagnosis of HTLV-1 or 2 infection, it is recommended that positive serologic samples should be confirmed by PCR assays or western blot (WB) analysis. Thus, the aim of this study was to develop and implement a simple reaction for the rapid identification of HTLV-1 and 2. Nested real-time PCR technique followed by high resolution melting was performed based on the tax/rex sequences of HTLV-1 (M2) and HTLV-2 (MoT) cell lines perfectly discriminating between HTLV-1 from HTLV-2, by distinct melting curve profiles. The sensitivity assay of this method revealed that at least 1 viral copy of HTLV-1 or 1·5 viral copy of HTLV-2 could be amplified. Later, this method was validated using 200 blood samples from corpses. In agreement with previous epidemiological, the HTLV-1 and 2 prevalence was 1·5% (CI 95%: 0·31-4·3) and 0·5% (CI 95%: 0·013-2·75), respectively. The strategy proposed herein has some advantages over other PCR-based tests because it not only reduces considerably time and the costs of the total diagnosis but also allows detection and discrimination of HTLV-1 and 2 in the same reaction.

International Health Policy Forum for the Elimination of HTLV: Advancing HTLV Health Policies around the World. Meeting Report, 10 November 2021

Human T cell lymphotropic virus (HTLV) infection affects mainly vulnerable population groups: people living in poverty in areas with very low human development indexes, sex workers, men who have sex with men, people who inject drugs, and epidemiologically closed and semi-closed population groups including traditional populations and indigenous people. This virus and its consequences have been neglected for decades, despite the high morbidity and mortality attributable to HTLV infection. Public health policies for HTLV-1/2 are considered scarce in the Region of the Americas and are usually limited to screening of blood donors. Scaling up HTLV-1/2 testing should be prioritized, and counseling of those living with HTLV-1 is an opportunity to prevent transmission. Testing pregnant women, followed by avoidance of or limited breastfeeding, should be a priority, and targeted testing for those at high risk of infection should be considered. Lack of awareness about HTLV is a major challenge, and PAHO/WHO engagement is crucial to surpass this obstacle. Inclusion of HTLV in existing programs, such as STI and maternal health, and programs focused on elimination of infectious diseases and neglected infections, was identified as an opportunity to facilitate implementation of health policies relating to HTLV-1/2 in the Region. Investment in research is needed to close gaps in knowledge and to develop cost-effective policies and tools supporting the advancement of successful public health responses such as low-cost point of care tests for HTLV-1/2 diagnosis. HTLV infection also has negative impact on the outcomes of co-infections that are common in the Region, including tuberculosis, strongyloidiasis, STIs, and mycosis. Genetic, environmental, and sociocultural aspects may influence HTLV-1 clustering or disease outcomes in the Region. Familial aggregation is also important and should be considered when evaluating the impact of HTLV-1 infections and designing policies to combat this virus. HTLV-2 is the predominant virus type among Amerindians. Successful policies to control this infection should rely on a combined approach to overcoming linguistic, cultural, and geographic barriers. This report highlights some of the main interventions available for the prevention and control of human T cell lymphotropic virus (HTLV) infection and its consequences and summarizes national and institutional experiences, discussions, successes, and challenges associated with the implementation of public health policies toward the elimination of HTLV infection. These topics were presented at the webinar “HTLV World Day 2021: International health policy forum for the elimination of HTLV – Advancing HTLV health policies around the world.”

Clinical and Laboratory Outcomes in HIV-1 and HTLV-1/2 Coinfection: A Systematic Review.

Aim: To perform a systematic review to describe the available findings on clinical outcomes in HIV-1 and HTLV-1/HTLV-2 co-infected individuals since 1995. Design: This Systematic Review used PECO criteria follow by PRISMA reporting guidelines and registered as CRD42021279062 (Prospero database). The Newcastle-Ottawa Scale assessed the methodological quality of included studies. Data Collection and Analysis: A systematical search in PubMed/MEDLINE, Embase, Web of Sciences databases for cross-sectional, case-control, or cohort studies design to identify clinical and laboratorial outcomes related to HIV-1 and HTLV-1/2 coinfection. Search strategy: [("HIV-1" AND "HTLV-1" OR "HTLV-2") AND ("Coinfection") AND (1990/01/01:2021/12/31[Date- Publication])]. Results: A total of 15 articles were included on this systematic review describing data of 2,566 mono and coinfected patients, 58% male, with mean age was 35.7 ± 5.7 years. HIV-1 and HTLV-1 coinfected patients were more likely to had shorter survival and faster progression to death or mortality than monoinfected ones. Coinfected had higher CD4 cell counts and less likelihood of ART use. In addition, higher frequency of diseases like ichthyosis (22.2 vs. 6.8%), scabies (18.6 vs. 0%), candidiasis (42 vs. 12%), Strongyloidiasis (15.4 vs. 2%) and neurological manifestations like encephalopathy, peripheral neuropathy and HAM/TSP were more frequently reported in coinfected patients. Conclusions: HIV-1 and HTLV-1 coinfection and HIV-1 and HTLV-1 /2 triple coinfection were related to shorter survival, higher mortality rate, and faster progression to death, while coinfection by HIV-1/HTLV-2 seems to have neutral association with longer survival, slower AIDS progression, and lower mortality rate. The available evidence indicates an urgent need for prevention and control measures, including screening, diagnosis, and treatment of HIV-1 and HTLV-1/2 coinfected patients. Test-and-treat strategy for patients living with HIV in areas endemic for HTLV infection is mandatory, to avoid the risks of delayed therapy and death for coinfected patients. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/, identifier: CRD42021279062.

The Relevance of a Diagnostic and Counseling Service for People Living With HTLV-1/2 in a Metropolis of the Brazilian Amazon.

Introduction: To identify the prevalence of infection in the urban area of the capital city of Belém, Brazil, the Laboratory of Virology of the Federal University of Pará implemented, as a public service, serological screening for human T-lymphotropic viruses 1 and 2 (HTLV-1/2) infection and, if necessary, counseling service and referral to specialized medical care. The project is funded by the National Council of Science and Technology, the Ministry of Health of Brazil and the Pan American Health Organization. Methods: From January 2020 to June 2021, 1,572 individuals of both sexes were approached to answer a questionnaire and were tested using an enzyme immunoassay (Murex HTLV-I+II, DiaSorin, Dartford, UK). Seropositive samples were confirmed as HTLV-1 and HTLV-2 infection by line immunoassay (INNO-LIA® HTLV I/II Score, Fujirebio, Japan) and/or by real-time polymerase chain reaction. G and Fisher's exact tests were applied to identify the association between epidemiological characteristics and HTLV-1/2 infection. Results: Of the 1,572 screened individuals, 63.74% were females between the ages of 30 and 59 years (49.04%). Infection was confirmed in six individuals (0.38%), among whom three (0.19%) were infected with HTLV-1 and three with HTLV-2 (0.19%). Blood transfusion before 1993 was the main risk factor associated with the route of exposure to the virus (p = 0.0442). The infected individuals were referred to a counseling session with a nursing professional, and two patients who manifested signs and symptoms suggestive of myelopathy associated with HTLV were referred to a neurologist. Conclusion: The implementation of the screening service revealed the occurrence of moderate endemicity of HTLV-1/2 in Belém, reinforcing the importance of continuing the service as a means of establishing an early diagnosis and providing counseling as a measure to prevent and control viral transmission in the general population.

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.

HTLV-1 and HTLV-2 Infection Among Warao Indigenous Refugees in the Brazilian Amazon: Challenges for Public Health in Times of Increasing Migration.

INTRODUCTION: Human T-lymphotropic virus (HTLV) infection is endemic in indigenous populations of the Americas. We describe herein the prevalence of HTLV-1 and HTLV-2 infection among Warao indigenous refugees from Venezuela living in Belém, Pará, Brazil. METHODS: In total, 101 individuals of both sexes (43 men and 58 women) between 18 and 77 years of age were investigated. Blood samples were collected and separated into plasma and leukocytes. Serological screening was performed using an enzyme-linked immunosorbent assay (ELISA; Murex HTLV-I+II, DiaSorin, Dartford, UK), and seropositive samples were submitted to proviral DNA extraction followed by real-time polymerase chain reaction (qPCR). A nested PCR of the env region (630 bp) followed by enzymatic digestion with XhoI was performed to identify the molecular subtype of HTLV-2, in addition to sequencing analysis of the 5'LTR-I and 5'-LTR-II regions. RESULTS: Of the 101 individuals analyzed, 3 (3.0%) were seropositive. Molecular analysis of the pol and tax genes confirmed the HTLV-1 infection in a 55-year-old woman and HTLV-2 infection in a man (68 years old) and a woman (23 years old). HTLV-2 strains were defined by enzymatic digestion as belonging to the HTLV-2b subtype. The sequencing of the 5'LTR regions confirmed the presence of subtype 2b and identified HTLV-1 as belonging to subtype 1A (Cosmopolitan) and the Transcontinental subgroup. Among the infected patients, it was possible to conduct medical interviews with two individuals after delivery of the result. One patient with HTLV-2 reported symptoms such as joint pain, foot swelling, frequent headache, dizziness and lower back pain. The HTLV-1-positive woman was diagnosed with a tumor, dementia, urinary incontinence, felt body pain, and had spots on her body. The presence of the HTLV-2b subtype highlights the prevalence of this molecular variant among indigenous South Americans, as well as the presence of HTLV-1 Transcontinental, which has a worldwide distribution. CONCLUSION: These results reveal a high prevalence of HTLV-1/2 infection among Warao immigrants, suggesting migratory flow as a virus spread mechanism among human populations and alert public authorities to the need to create epidemiological surveillance programs, public social and health policies aimed at welcoming immigrants in the Brazilian territory.