[HTLV-I/II infection in the state of Bahia]

Human T Cell Lymphotropic Virus Type 1 Global Prevalence Associated with the Human Development Index: Systematic Review with Meta-Analysis

In 2012, the number of people infected with human T cell lymphotropic virus type 1 (HTLV-1) was estimated to be 10 million worldwide. Prevalence varies according to geographic location, ethnic factors, sex, age, populations exposed to risk factors, income, and education, reaching countries with the worst socioeconomic scenarios. There is a need to determine the current global prevalence of HTLV-1 and examine its association with countries' human development index (HDI) to provide data for global health policy. Systematic review with meta-analysis is according to PRISMA 2020 recommendations. It was registered at PROSPERO, CRD42021223146. Prevalence or cross-sectional studies of HTLV-1 infection with at least 100 participants, screening, and confirmatory serologic testing were included. Studies with incomplete or unavailable results or with duplicate information were excluded. Data were selected by two independent investigators and analyzed using R software, a metapackage that generated the forest plots [95% confidence interval (CI)]. Heterogeneity was assessed using the I² statistic, and funnel plot asymmetry was assessed using Egger's test. Countries were compared using an HDI cutoff ≥0.8. Methodological quality was assessed using Joanna Briggs Institute (JBI) criteria. The overall prevalence of HTLV-1 infection was 0.91% (95% CI: 0.80-1.02, p < .0001) and was higher in low HDI countries [1.18% (95% CI: 1.03-1.34)] than in high HDI countries [0.41% (95% CI: 0.27-0.57)]. Prevalence varied according to the populations studied: it was higher in the general population [1.65% (95% CI: 1.08-2.34)] compared to pregnant women [0.34% (95% CI: 0.17-0.57)] and blood donors [0.04% (95% CI: 0.01-0.08)]. Consistently, prevalence for each population group was higher in low HDI countries than in high HDI countries. The worldwide prevalence of HTLV-1 infection is highly heterogeneous, with a global prevalence of 0.91%. In high HDI countries, the observed prevalence is approximately three times lower than in low HDI countries. In the general population, the observed prevalence is about 5 times higher than in pregnant women and 41 times higher than in blood donors.

Lymphotropic Viruses EBV, KSHV and HTLV in Latin America: Epidemiology and Associated Malignancies. A Literature-Based Study by the RIAL-CYTED

The Epstein-Barr virus (EBV), Kaposi sarcoma herpesvirus (KSHV) and human T-lymphotropic virus (HTLV-1) are lymphomagenic viruses with region-specific induced morbidity. The RIAL-CYTED aims to increase the knowledge of lymphoma in Latin America (LA), and, as such, we systematically analyzed the literature to better understand our risk for virus-induced lymphoma. We observed that high endemicity regions for certain lymphomas, e.g., Mexico and Peru, have a high incidence of EBV-positive lymphomas of T/NK cell origin. Peru also carries the highest frequency of EBV-positive classical Hodgkin lymphoma (HL) and EBV-positive diffuse large B cell lymphoma, not otherwise specified (NOS), than any other LA country. Adult T cell lymphoma is endemic to the North of Brazil and Chile. While only few cases of KSHV-positive lymphomas were found, in spite of the close correlation of Kaposi sarcoma and the prevalence of pathogenic types of KSHV. Both EBV-associated HL and Burkitt lymphoma mainly affect young children, unlike in developed countries, in which adolescents and young adults are the most affected, correlating with an early EBV seroconversion for LA population despite of lack of infectious mononucleosis symptoms. High endemicity of KSHV and HTLV infection was observed among Amerindian populations, with differences between Amazonian and Andean populations.

Evidence of New Endemic Clusters of Human T-Cell Leukemia Virus (HTLV) Infection in Bahia, Brazil

Background

Salvador, Bahia (northeastern Brazil), has been identified as the epicenter of Human T-cell leukemia virus Human T-cell leukemia virus (HTLV) type 1 infection in the country. This study aims to estimate the rate of HTLV infection and the geographical distribution of this virus in this state.

Methods

All HTLV tests (chemiluminescence/ELISA assays/Western Blotting) performed in the Central Laboratory of Public Health of Bahia (LACEN) from 2004 to 2013 were included. Data was extracted from LACEN’s database using high volume extract, transformation and load throughput. Infection rate was expressed as the number of infected individuals per 100,000 inhabitants considering municipalities grouped in microregions and/or mesoregions as the unit of analysis.

Results

A total of 233,876 individuals were evaluated. Individuals were from 394 out of 417 municipalities of Bahia (94.5%). HTLV chemiluminescence/ELISA assay was found to be reactive for 3,138 individuals from whom 2,323 had WB results (1,978 positives, 62 negative and 282 indeterminate). Out of 1978 reactive samples, 1,813 (91.7%) were positive for HTLV-1, 58 (2.9%) for HTLV-2 and 107 (5.4%) were for both HTLV-1 and HTLV-2. The cumulative mean rate of HTLV-positive cases in Bahia was 14.4 per 100,000 inhabitants. Three microregions presented rates >20 HTLV-positive cases/100,000 inhabitants: Barreiras (24.83 cases per 100,000 inhabitants), Salvador (22.90 cases per 100,000 inhabitants), and Ilhéus-Itabuna (22.60 cases per 100,000 inhabitants).

Conclusion

HTLV infection is disseminated in the state of Bahia, with an overall moderate rate of infection. Further studies should be conducted to characterize the epidemiological and clinical profile of HTLV-infected individuals better and to propose effective prevention measures.

Moderate endemicity of the human T-lymphotropic virus infection in the metropolitan region of Belém, Pará, Brazil

INTRODUCTION

The spread of the HTLV infection in families living in the metropolitan area of Belém, Pará, Brazil, and the lack of studies in the general population requires studies to better understand its prevalence in the region.

METHODS

An anti-HTLV-1/HTLV-2 antibodies test was carried out on random adults in public places in Belém between November 2014 and November 2015. A proviral DNA test detected if the person was infected, and then a clinical evaluation and an intrafamilial investigation were carried out.

RESULTS

Of the 1059 individuals being investigated, 21 (2.0%) had seroreagent samples, 15 (1.4%) had HTLV-1, 5 (0.5%) had HTLV-2, and proviral DNA was undetectable in one case. The mean age of the infected people (57.2) was higher than that of those that were uninfected (46.2) (p = 0.0010). The prevalence of infection increased with age, especially in individuals with a family income equal to or less than a minimum wage. Intrafamilial transmission seems to have occurred in all of the families being studied. Among the patients with HTLV-1, 30% (3/10) already had some symptom related to the infection.

DISCUSSION

The increase in prevalence rates according to age may be due to late seroconversion of a previously acquired infection, or the cumulative risk of new infections, especially in women.

CONCLUSION

There was a moderate prevalence of the HTLV infection among adult individuals from the metropolitan area of Belém, with a predominance of HTLV-1. This infection was associated with low income and increasingly older women. It also presented intrafamily spread and negligence in the diagnosis of associated diseases.

Comparison between the spastic paraplegia rating scale, Kurtzke scale, and Osame scale in the tropical spastic paraparesis/myelopathy associated with HTLV

INTRODUCTION

The objective of this study was to compare Osame's scale of motor incapacity and the expanded scale of the state of incapacity of Kurtzke with the spastic paraplegia rating scale for the clinical evaluation of patients with HTLV-I-associated myelopathy/tropical spastic paraparesis (HAM/TSP).

METHODS

Patients with the diagnosis of infection by HTLV-I/HTLV-II and with the clinical suspicion of HAM/TSP were included in the study.

RESULTS

There were 45 patients who were evaluated. When analyzing the results of the scales, the researchers found the following averages of 21.08 points for the spastic paraplegia rating scale, 4.35 points for Osame's scale, and 4.77 points for Kurtzke's scale. The relation between the scale of paraplegia with Osame's was very significant with p < 0.0001, and regarding Kurtzke's scale, there was a similar result of p < 0.0001. When comparing Osame's, Kurtze's, and the spastic paraplegia rating scale with the time of disease, the researchers found a significant result of p = 0.0004 for the scale of spastic paraplegia, p = 0.0018 for Osame's scale, and p < 0.0001 for Kurtzke's scale.

CONCLUSION

The spastic paraplegia rating scale has a good relation with Osame's and Kurtzke's scales showing a p index that is very significant that indicates that, although the scale was not initially made to be applied to patients with HAM/TSP because of the infection by HLTV, it showed to be as efficient as Osame's and Kurtzke's scales in evaluating the patients' neurological conditions.

Declínio da prevalência do HTLV-1/2 em doadores de sangue do Hemocentro Regional da Cidade de Uberaba, Estado de Minas Gerais, 1995 a 2008

INTRODUCÃO: Estudo retrospectivo com o objetivo de avaliar a prevalência e fatores associados à soropositividade para o HTLV-1/2, no período de 1995 a 2008, no Hemocentro Regional de Uberaba e descrever os doadores soropositivos quanto ao gênero, idade, estado civil, cor de pele e procedência. MÉTODOS: Foram realizados análise estatística descritiva, testes qui-quadrado e odds ratio para comparação de proporções e gráfico de dispersão com coeficiente de correlação linear. RESULTADOS: Dentre x doadores testados, foi encontrada a prevalência de sorologia positiva para o HTLV de 0,02% e indeterminada de 0,09%. Houve uma redução significativa da sorologia positiva para HTLV, no período de 2002 a 2008, em comparação ao período de 1995 a 2001. Dentre os soropositivos, observou predomínio significante no gênero feminino. CONCLUSÕES: Imputamos a queda gradativa de soropositividade no período à exclusão permanente dos doadores de repetição soropositivos e ao aprimoramento dos métodos de triagem clínica e dos testes sorológicos ao longo dos anos com reflexos positivos na segurança transfusional.

Phylogenetic and molecular analysis of HTLV-1 isolates from a medium sized town in northern of Brazil: tracing a common origin of the virus from the most endemic city in the country

Salvador-Bahia has the highest prevalence of HTLV-1 infection in Brazil; about 2% of the population is infected. In this city, the prevalence of HTLV in pregnant women is 1%. There is no data of the HTLV-1 prevalence in others cities of the Bahia's Recôncavo, where the population has similar social and demography characteristics to those from Salvador. Our aim was to evaluate the seroprevalence of HTLV in pregnant women in Cruz das Almas-Bahia, a medium-sized city from the Bahia's Recôncavo. All individuals were tested for HTLV (ELISA) and the positive samples were confirmed by Western Blot. Phylogenetic analyses of the total LTR region were performed in all positive samples. We tested 408 samples (45.4% of the estimate pregnant women population) between June 1st and October 31, 2005. The prevalence of HTLV-1 infection was 0.98%. In addition, all isolated virus were grouped in the subtype HTLV-1a, in the Latin American group. Our results suggest that the introduction of HTLV-1 occurred after the slave trade into Salvador. In addition, HTLV-1-infection should be screened during the pregnancy in women originating from HTLV-1 endemic areas.

Identification of clonally rearranged T-cell receptor beta chain genes in HTLV-I carriers as a potential instrument for early detection of neoplasia

We analyzed the genetic recombination pattern of the T-cell receptor beta-chain gene (TCR-beta) in order to identify clonal expansion of T-lymphocytes in 17 human T-lymphotropic virus type I (HTLV-I)-positive healthy carriers, 7 of them with abnormal features in the peripheral blood lymphocytes. Monoclonal or oligoclonal expansion of T-cells was detected in 5 of 7 HTLV-I-positive patients with abnormal lymphocytes and unconfirmed diagnosis by using PCR amplification of segments of TCR-beta gene, in a set of reactions that target 102 different variable (V) segments, covering all members of the 24 V families available in the gene bank, including the more recently identified segments of the Vbeta-5 and Vbeta-8 family and the two diversity beta segments. Southern blots, the gold standard method to detect T-lymphocyte clonality, were negative for all of these 7 patients, what highlights the low sensitivity of this method that requires a large amount of very high quality DNA. To evaluate the performance of PCR in the detection of clonality we also analyzed 18 leukemia patients, all of whom tested positive. Clonal expansion was not detected in any of the negative controls or healthy carriers without abnormal lymphocytes. In conclusion, PCR amplification of segments of rearranged TCR-beta is reliable and highly suitable for the detection of small populations of clonal T-cells in asymptomatic HTLV-I carriers who present abnormal peripheral blood lymphocytes providing an additional instrument for following up these patients with potentially higher risk of leukemia.

Soroprevalência de vírus linfotrópico de células T humanas, vírus da imunodeficiência humana, sífilis e toxoplasmose em gestantes de Botucatu - São Paulo - Brasil: fatores de risco para vírus linfotrópico de células T humanas

Com o objetivo de estudar a soroprevalência de vírus linfotrópico de células T humanas I/II (HTLV-I/II), vírus da imunodeficiência humana, sífilis e toxoplasmose, em gestantes atendidas em unidade básicas de saúde do município de Botucatu - São Paulo - Brasil, bem como os fatores de risco para a infecção pelo HTLV -I/II, foram realizados inquérito sorológico e avaliação dos resultados de exames solicitados na rotina do prénatal. Em 913 gestantes, a soroprevalência de HTLV- I e de HTLV- II foi de 0,1%. Sífilis, toxoplasmose e infecção pelo HIV foram encontradas. Nenhum dos fatores de risco pesquisados mostrou-se seguro para identificar gestantes com infecção pelo HTLV- I/II. A comparação da proporção de gestantes infectadas e de doadores de sangue da região sudeste do Brasil com testes reagentes para HTLV- I/II não mostrou diferença estatística.

Prevalência da infecção pelo vírus linfotrópico humano de células T e fatores de risco associados à soropositividade em doadores de sangue da cidade de Rio Branco, AC, Brasil (1998-2001)

Para cada doador de sangue soropositivo (ELISA, Abbott®) para HTLV-I/II, de dezembro de 1998 a março de 2001, também foram selecionados dois soronegativos. As amostras séricas foram re-testadas pelo ELISA (Murex®) e aquelas que permaneceram soropositivas foram testadas pelo Western Blot e pela PCR. Das 11.121 amostras séricas, 73 (0,66%) foram positivas (Abbott®), mas somente 12 (0,11%) permaneceram positivas (Murex®), enquanto que as 146 soronegativas foram confirmadas, apesar de ser sofrível o índice de concordância entre os dois ELISA. O Western Blot confirmou as 12 amostras como soropositivas: 8 (0,07%) HTLV-I; duas (0,02%) HTLV-II e duas (0,02%) indeterminadas - sendo pela PCR uma pelo HTLV-I e a outra pelo HTLV-II. Em conclusão, nessa população da Amazônia Ocidental foi muito baixa a soroprevalência de HTLV-I/II, apesar de ser esperada maior prevalência do HTLV-II devido a grande miscigenação racial indígena.

Retrovirus infections in a sample of injecting drug users in Rio de Janeiro City, Brazil: prevalence of HIV-1 subtypes, and co-infection with HTLV-I/II

BACKGROUND

Retrovirus infections among injecting drug users (IDUs), a core at-risk population for both HIV-1 and HTLV-I/II infections in Brazil, were assessed within an ongoing cooperative research.

OBJECTIVE

The study assessed the seroprevalences of HIV-1 and HTLV-I/II infections, as well as the prevalence of HIV-1 subtypes in a sample of IDUs from Rio de Janeiro, Brazil. An attempt to evaluate HIV incidence was carried out using a dual 'sensitive/less sensitive' testing strategy.

STUDY DESIGN

Cross-sectional evaluation of 175 IDUs. Serostatus for HIV-1 and HTLV-I/II were established by enzyme-linked immunosorbent assays, and confirmed by western blot. The dual testing strategy aimed to estimate HIV-1 incidence rates. Differentiation between HTLV-I and -II was performed by western blot. DNA samples were polymerase chain reaction amplified by a nested protocol, and HIV-1 subtyping was determined by heteroduplex mobility assay.

RESULTS

Forty-six and 29 samples were found to be, respectively, positive for HIV-1 and HTLV-I/II, 15 of them co-infected by both viruses. Among HTLV-I/II-infected patients, 75.9% were infected by HTLV-I. Thirty-one HIV samples were identified as B subtype, with seven of them showing the typical "Brazilian B" pattern in the gp120 V3 loop, and ten were identified as F subtype. The use of less sensitive assays for HIV infection wrongly identified a deeply immunocompromised patient as an incident case.

CONCLUSION

Moderately high seroprevalences were found for both HIV-1 and HTLV-I/II infections, HIV-1/HTLV-I co-infections being of special concern. A non-statistically significant higher prevalence of F subtype was observed, when compared with the distribution of F/B subtypes among Brazilian patients from other exposure categories. No recent HIV-1 infections were detected, but a limitation of the "sensitive/less-sensitive" testing strategy was made evident.