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.

HTLV-1-Associated Myelopathy/Tropical Spastic Paraparesis Is Not Associated with SNP rs12979860 of the IL-28B Gene.

The present study investigated the association between the rs12979860 polymorphism in the IL-28B gene and HTLV-1 infection as well as the development of HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP). HTLV-1-infected patients (26 HAM/TSP symptomatic and 53 asymptomatic) and 300 seronegative healthy controls were investigated. Plasma levels of the cytokines TNF-α, TNF-ß, IL-8, IL-10, IL-6, and IFN-γ from infected patients were measured using an indirect enzyme-linked immunosorbent assay. The HTLV proviral load was measured using a real-time PCR assay, and T-cell subset counts were determined by flow cytometry. Real-time PCR was used to genotype the rs12979860 SNP. The allelic and genotypic distributions displayed no significant differences among the investigated groups. No significant association between the serum cytokine levels and the presence of the rs12979860 SNP in symptomatic and asymptomatic subjects was observed. A positive correlation (p = 0.0015) between TNF-ß and IFN-γ was observed in the asymptomatic group, but a positive correlation was only observed (p = 0.0180) between TNF-α and IL-6 in the HAM/TSP group. The proviral load was significantly higher in HAM/TSP patients than in asymptomatic subjects. The present results do not support a previous report indicating an association between the SNP rs12979860 and HAM/TSP outcome.

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.

Virulence factors of Candida albicans isolates from the oral cavities of HIV-1-positive patients.

The present study assessed the phenotypic aspects of oral-cavity Candida albicans isolates from 300 HIV-1- positive patients, relating the most commonly investigated virulence factors (enzyme typing and germ-tube formation) to the most common morphotypes. The samples were seeded into specific media for isolation and subsequent identification using the automated Vitek 2 system. The following assays were performed for phenotypic characterization: morphotyping, germ-tube formation and enzyme typing. Out of 300 collected samples, 144 tested positive for yeasts of the Candida genus, 98 (32.7 %) of which were identified as C. albicans. The latter samples were attributed to seven different morphotypes; the three most common morphotypes were 7208 (49 %), 7308 (14.3 %) and 3208 (13.3 %). All of the C. albicans isolate samples formed germ tubes and produced the enzymes proteinase and phospholipase, with an activity classified as intermediate to high. Due to the identification of virulence factors among the analyzed samples, monitoring of HIV-1-positive patients colonized by different morphotypes must be established because these morphotypes are extremely pathogenic and can trigger severe fungal infections.

No evidence of association between MBL2A/O polymorphisms and Mycobacterium tuberculosis infection in populations from the Brazilian Amazon region.

The present study investigated the prevalence of the polymorphisms in the exon 1 of the MBL2 gene in patients with tuberculosis at a hospital in northern Brazil, which is a regional reference for the treatment of the disease. The study group was composed of 167 patients with tuberculosis, 34 of which had the extra-pulmonary form of the disease, while the other 133 had the pulmonary type. The control group consists of 159 healthy individuals. Samples of DNA extracted from leucocytes were submitted to Polymerase Chain Reaction for the amplification of a 120-bp segment of exon 1 of the MBL2 gene. The distribution of allele and genotype frequencies varied little among the different groups, and it was not possible to establish any clear association between the variants of the MBL2 gene and the susceptibility to or clinical profile of tuberculosis infections in the population analyzed.

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.

IFNG +874T/A polymorphism and cytokine plasma levels are associated with susceptibility to Mycobacterium tuberculosis infection and clinical manifestation of tuberculosis.

Regarding the importance of interferon-gamma (IFN-gamma) in protective immunity against Mycobacterium tuberculosis and the functional role of IFNG +874T/A single nucleotide polymorphism (SNP) in the IFN-gamma production, the present study investigated the relationship of this genetic polymorphism with susceptibility to tuberculosis (TB). A total of 129 patients with pulmonary tuberculosis (PTB), 33 with extrapulmonary tuberculosis (EPTB), and 156 control subjects were studied. Blood samples were drawn and plasma was used to measure IFN-gamma serum concentration by enzyme-linked immunoassay. DNA samples were extracted from leukocytes and used to investigate +874T/A polymorphism in IFNG gene using allele-specific oligonucleotide-polymerase chain reaction. An association between the presence of the allele +874A and the genotype +874AA with the active tuberculosis was found (p < 0.0001, 95% confidence interval = 1.64-3.22), at the same time that allele + 874T and genotype +874T/T were more frequent in the control group. The average plasma concentration of IFN-gamma among patients with tuberculosis was significantly lower than in the control group, and were lower in the EPTB group than in the group with PTB, suggesting a relationship of low plasma levels of this cytokine with active tuberculosis and the progression to more serious forms of the disease. Furthermore, we observed the association of the +874T/T and +874A/A genotypes with high and low IFN-gamma plasma concentrations, respectively, both in TB patients and in the control groups. Thus our findings suggest an association of the IFNG +874T/A polymorphism with susceptibility to M. tuberculosis infection in the studied population.

Molecular epidemiology of HIV type 1 in northern Brazil: identification of subtypes C and D and the introduction of CRF02_AG in the Amazon region of Brazil.

The molecular epidemiology of HIV-1 strains circulating in Belem-PA and Macapa-AP, in the Northern region of Brazil, is described using sequences of the C2V3 segment of the env and the pro gene of HIV-1 from patients of the Reference Unit for Special Infectious and Parasitary Diseases (URE-DIPE) in Belem-PA and the Central Laboratory (LACEN) in Macapa-AP. Subtype B was the most frequently found in relation to pro (88.3%) in Belem and in Macapa (97.1%) and env (88.3% in Belem and 100% in Macapa). Subtype F was also described in Belem (9.3% pro and 8.3% env) and Macapa (2.8% pro). Subtype D was described for the first time in the Northern region of the country as well as the recent entry of CRF02_AG. Furthermore, several possible recombinant forms among the various subtypes were found in both cities. The results support the hypothesis that HIV-1 infection is associated with the epidemic of the virus in the Southeast region of the country and that the city of Belem is the most important route for HIV-1 entry in the Northern region of Brazil.

Mannose-binding lectin gene polymorphisms are not associated with susceptibility to hepatitis C virus infection in the Brazilian Amazon region.

The present study compares the genotype frequencies between two population groups composed by 73 hepatitis C virus (HCV)-infected patients and 92 seronegative controls and investigates the role of allele variants as a possible factor in the susceptibility to HCV infection and the influence on disease progression. The identification of MBL*B and MBL*C alleles was performed by restriction fragment length polymorphism analysis of the 349-bp product using BanI and MboII restriction enzymes, respectively, and a polymerase chain reaction-sequence-specific polymorphism for discrimination of MBL*D. The analysis of allele and genotype frequencies between an HCV-infected group and seronegative controls did not indicate significant differences. The comparison of chronically infected subjects with and without liver cirrhosis was also not statistically significant. The odds ratio estimations were not significant, and the values obtained cannot suggest that the presence of allele variant MBL*B could have some influence in the risk of HCV infection progression to liver cirrhosis and that the presence of allele MBL*D could confer some protection against disease progression, but a larger sample size is necessary to confirm the present results.

[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 typing of HIV type 1 infection in the Tiriyo tribe, a native Indian community of the Amazon region of Brazil.

The seroprevalence and the occurrence of an HIV-1 subtype was assessed in blood samples of the Tiriyo tribe. Antibody was found in 0.6% and the molecular analysis of the pro region detected the emergence of a subtype B for the first time in a native Indian tribe of the Amazon region of Brazil.

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.