Isolation of the Arawete and Asurini Indians keeps the tribes free from HTLV infection during 36 years of follow-up.

Arawete and Asurini Indian tribes were revisited after a 36-year follow-up in search of HTLV infections. 46 persons (23 from each tribe) were tested for HTLV-1/2 antibodies and viral DNA. None were positive; this was probably because of their social/cultural isolation from neighboring tribes where HTLV-2c is hyperendemic.

Human T-lymphotropic virus 1aA circulation and risk factors for sexually transmitted infections in an Amazon geographic area with lowest human development index (Marajó Island, Northern Brazil).

BACKGROUND: This cross-sectional study evaluated the prevalence of infection with human T-lymphotropic virus 1 and 2 (HTLV-1 and HTLV-2) in a population from the municipalities of Anajás, Chaves, São Sebastião da Boa Vista (SSBV) and Portel in the Marajó Archipelago and correlated these data with the epidemiological characteristics of the study population. METHODS: A total of 1899 biological samples were evaluated. The samples were screened for the presence of anti-HTLV antibodies using an enzyme-linked immunosorbent assay (ELISA), and infection was confirmed using conventional polymerase chain reaction (PCR), real-time PCR and nucleotide sequencing. RESULTS: Eleven samples (0.58%) were seropositive for HTLV, but molecular analysis confirmed positivity in only two samples (0.11%). Nucleotide sequencing and phylogenetic analysis indicated that the two samples positive for HTLV-1 that were isolated in Chaves belonged to the Cosmopolitan subtype 1 (HTLV-1a) and Transcontinental subgroup (A). CONCLUSION: Our results confirmed the presence of Cosmopolitan Transcontinental HTLV-1 in the Marajó Archipelago, Amazon region, and the majority of the population revealed a lack of knowledge about sexually transmitted infections, which increases the risk of dissemination of HTLV and other agents.

FAS and FASL gene polymorphisms are not associated with hepatitis B virus infection based on a case-control study in a Brazilian population.

OBJECTIVE: This study investigated the association of the single nucleotide polymorphisms (SNPs) in the FAS and FASL genes with the outcome of hepatitis B virus (HBV) infection. METHODS: Blood samples were collected from 116 HBV-infected patients at the Hospital of the Santa Casa de Misericordia Foundation (Belém, PA, Brazil). Seronegative individuals were used as controls. DNA samples were extracted from the leukocytes and assayed using the polymerase chain reaction (PCR) followed by RFLP analysis with restriction endonucleases. RESULTS: The frequencies of the mutant genotypes for -670FAS (GG), Ivs2nt-124FASL (GG), Ivs3nt-169FASL (ΔT/ΔT), and -844FASL (TT) were higher in the HBV patients, and the FAS-1377AA genotype was more frequent in the control group; however, the differences between the allele and genotype frequencies were not statistically significant. When the HBV patient population was divided into two groups (inactive carriers and active chronic hepatitis patients), the mutant genotypes were found to be more prevalent in the active chronic hepatitis group with respect to the FAS gene polymorphisms; however, this difference was not statistically significant. CONCLUSIONS: The results suggest that the polymorphisms in FAS and FASL genes are not associated with HBV infection or even with the natural history of the infection in the Brazilian Amazon region.

Human T-cell lymphotropic virus in patients infected with HIV-1: molecular epidemiology and risk factors for transmission in Piaui, Northeastern Brazil.

This study aimed to describe the epidemiological, immunological and molecular features of infection by the human T-lymphotropic virus-1/2 (HTLV-1/2) in individuals with HIV-1 in an urban area of Piaui State, Brazil. Exclusion criteria included patients under 18 years of age, pregnant women or Amerindians. Of 805 individuals analyzed by the serological method (ELISA) for the detection of anti-HTLV-1/2, 18 (2.24%) were positive, but only 13 (1.61%) were confirmed by PCR. The RFLP analysis revealed that nine (1.12%) of these subjects were positive for HTLV-1 and four (0.5%) for HTLV-2. The mean age of these co-infected individuals was 50.9±9.1 years, and a significant association was found with age (above 40 years: p = 0.002), minor surgeries (p = 0.004) and blood transfusion (p = 0.031). Quantification of the T CD4+/CD8+ lymphocytes and the HIV-1 viral load showed no significant association of T CD8 + lymphocyte levels with co-infection in the patients with HIV-1/HTLV-1. The sequencing of the LTR region and phylogenetic analysis indicated that the nine HTLV-1 strains belong to the Transcontinental subgroup of the Cosmopolitan group (1a), with a 83% (neighbor-joining) bootstrap value. The HTLV-2 strains were identified as subtype HTLV-2c, supported by a bootstrap value of 79%. Further studies in other population subgroups, such as blood donors and drug users, will be necessary to clarify the dissemination of HTLV-1/2 in Piau and elucidate the developmental profile of the virus in the region.

FAS-670A/G single nucleotide polymorphism may be associated with human T lymphotropic virus-1 infection and clinical evolution to TSP/HAM.

FAS and FASLG genes are closely linked to the apoptosis mechanism of the immune system and several polymorphisms in these genes have been associated with susceptibility to diseases. The present study investigated the polymorphisms at positions -670 in the FAS gene, and -169 and -124 in the FASLG gene, among HTLV-1 infected subjects. Blood samples from HTLV infected subjects and seronegative individuals were collected, and polymorphisms were analyzed using a polymerase chain reaction (PCR) followed by RFLP analysis using restriction endonucleases. The genotype frequencies of the FAS -670 polymorphism was the only one that showed a higher and significant prevalence of genotype -670GG among HTLV-1 infected subjects as compared to the control group (p=0.0160), but the genotype -670AA was more frequent among TSP/HAM patients as compared to the asymptomatic individuals (p=0.0005). TCD4(+) and TCD8(+) lymphocyte counts from HTLV infected and seronegative subjects, as well as the proviral load values, according to the status of symptomatic and asymptomatic infection carrying different genotypes were compared but showed no statistical significance. The present results suggest that FAS -670 polymorphism seems to be associated with susceptibility to HTLV-1 and may increase the chance to develop TSP/HAM among HTLV-1 infected persons.

[Molecular characterization of HTLV-1 among patients with tropical spastic paraparesis/HTLV-1 associated myelopathy in Belém, Pará]. / Caracterização molecular do HTLV-1 em pacientes com paraparesia espástica tropical/mielopatia associada ao HTLV-1 em Belém, Pará.

The present study evaluated the occurrence of HTLV-1 and its subtypes in blood samples of patients presenting symptoms of tropical spastic paraparesis/HTLV-1 associated myelopathy. The detection of HTLV infection was performed by serological and molecular assays. Five patients were infected by HTLV-1 of the Cosmopolitan subtype, subgroup Transcontinental. The results confirm the occurrence of HTLV-1 infection among patients with clinical diagnosis of tropical spastic paraparesis/HTLV-1 associated myelopathy in Belém, Pará.

Caracterização molecular do HTLV-1 em pacientes com paraparesia espástica tropical/mielopatia associada ao HTLV-1 em Belém, Pará / Molecular characterization of HTLV-1 among patients with tropical spastic paraparesis/HTLV-1 associated myelopathy in Belém, Pará

O presente estudo avaliou a ocorrência da infecção pelo HTLV-1 e seus subtipos em amostras de sangue de pacientes com diagnóstico clínico de paraparesia espástica tropical/mielopatia associada ao Htlv-1. A detecção da infecção pelo HTLV realizou-se através de testes sorológico e molecular. Cinco amostras estavam infectadas pelo HTLV-1 do subtipo Cosmopolita, subgrupo Transcontinental. Os resultados obtidos confirmam a ocorrência de infecção pelo HTLV-1 em pacientes com diagnóstico clínico de paraparesia espástica tropical/mielopatia associada ao Htlv-1em Belém, Pará.

The present study evaluated the occurrence of HTLV-1 and its subtypes in blood samples of patients presenting symptoms of tropical spastic paraparesis/HTLV-1 associated myelopathy. The detection of HTLV infection was performed by serological and molecular assays. Five patients were infected by HTLV-1 of the Cosmopolitan subtype, subgroup Transcontinental. The results confirm the occurrence of HTLV-1 infection among patients with clinical diagnosis of tropical spastic paraparesis/HTLV-1 associated myelopathy in Belém, Pará.

Serological and molecular evidence of HTLV-I infection among Japanese immigrants living in the Amazon region of Brazil.

Human T-lymphotropic virus type I (HTLV-I) infection was investigated in 168 Japanese immigrants (64 males and 104 females) living in the Tome-Acu county located in the State of Para, Brazil. The serological screening was performed using an enzyme-linked immunosorbent assay, and showed the presence of anti-HTLV in four women whose ages ranged from 50 to 88. Confirmation of infection and discrimination HTLV typing was performed using a nested PCR on the extracted DNA targeting the pX region. In three of the samples, infection was confirmed to be HTLV-I. Sequencing HTLV-I 5'LTR and the RFLP pattern using DraI and SacI endonucleases indicated that the virus is a member of the Cosmopolitan group. These three women originated from the Kyushu region, though two of the corresponding HTLV-I strains were phylogenetically related to the Japanese subgroup and the third to the Transcontinental subgroup, which probably reflects the geographical origin of the infected individuals. The Japanese community residing in the northern Brazil apparently have not contributed to increase the prevalence of HTLV-I in the country.

Serological survey for hepatitis c virus (HCV) infection among two population groups from the Amazon Region of Brazil

Objetivo: No presente trabalho a avaliação sorológica da infecção pelo VHC foi investigada em duas populações da Região Amazônica do Brasil. Método: Um total de 200 amostras de soro (115 pacientes residentes em Belém, Estado do Pará, procedentes do Laboratório de Análises Clínicas do Centro de Ciências Biológicas da Universidade Federal do Pará e 85 indivíduos descendentes de escravos africanos residentes na comunidade de Trombetas, Norte do Brasil), foi testado para a presença de anti-VHC, usando um ensaio imunoenzimático (ELISA). Resultado: Um paciente, do sexo feminino, 53 anos, foi o único caso de sororreatividade (0,8por cento) para anti-VHC em Belém. Na vila de Trombetas, dois indivíduos, do sexo feminino, apresentaram sororreatividade para anti-VHC (2,35por cento). A avaliação do questionário epidemiológico mostrou que o principal fator de risco para infecção pelo VHC mencionado pela paciente residente em Belém, foi o contato sexual sem uso de preservativo com usuário de drogas. O fator de risco para a transmissão do VHC no mocambo de Trombetas não pôde ser identificado devido à ausência de informações epidemiológicas. Conclusão: Estes resultados enfatizam a necessidade de estudos soroepidemiológicos que objetivem detectar a real soroprevalência da infecção pelo VHC na região amazônica do Brasil e os principais fatores de risco associados

Molecular epidemiology of human T-lymphotropic virus type II infection in Amerindian and urban populations of the Amazon region of Brazil.

Molecular characterization of human T-cell lymphotropic virus II (HTLV-II) isolates in North America and Europe has shown the existence of two principal subtypes of the virus, HTLV-IIa and HTLV-IIb. Subsequent studies on HTLV-II isolates from Brazil have suggested the existence of a unique variant phylogenetically related to HTLV-IIa but phenotypically similar to HTLV-IIb with respect to the transactivatory protein, Tax. This variant has been designated HTLV-IIc. To better clarify the variability and distribution of HTLV-II in Brazil, the viruses present in two population groups from the Amazon region were tested for the presence of HTLV-II using serological and molecular assays. The groups consisted of blood donors from three Amerindian communities and of HIV-1/HTLV-II coinfected patients residing in Belém, an urban area. Nucleotide sequences and phylogenetic analysis confirmed the presence of HTLV-IIc subtype among Amerindian populations and, for the first time, the presence of the same virus among urban groups in Belém. The isolated occurrence of the HTLV-IIc subtype among Amerindian populations in the Amazon region could be attributed to (1) the different migratory pathways and founder effect, or (2) the local origin of a proto-HTLV-II carried by Amerindian ancestors who migrated to the Amazon circa 11,000 to 13,000 years ago. These results suggest that not only is HTLV-IIc unique to this region, but that its presence in urban areas of Brazil has resulted from admixture processes during the colonization of the country.