[show abstract][hide abstract] ABSTRACT: Hepatitis B virus (HBV) genotype F (HBV/F) is considered to be indigenous to the Americas, but its emergence and spread in the continent remain unknown. Previously, only two HBV/F complete genome sequences from Brazil were available, limiting the contribution of Brazilian isolates to the phylogenetic studies of HBV/F. The present study was carried out to assess the proportion and geographic distributions of HBV/F subgenotypes in Brazil, to determine the full-length genomic sequences of HBV/F isolates from different Brazilian geographic regions, and to investigate the detailed evolutionary history and phylogeography of HBV/F in Brazil.
Complete HBV/F genomes isolated from 12 Brazilian patients, representing the HBV/F subgenotypes circulating in Brazil, were sequenced and analyzed together with sequences retrieved from GenBank, using the Bayesian coalescent and phylogeographic framework.
Phylogenetic analysis using all Brazilian HBV/F S-gene sequences available in GenBank showed that HBV/F2a is found at higher frequencies countrywide and corresponds to all sequences isolated in the Brazilian Amazon Basin. In addition, the evolutionary analysis using complete genome sequences estimated an older median ancestral age for the Brazilian HBV/F2a compared to the Brazilian HBV/F1b and HBV/F4 subgenotypes, suggesting that HBV/F2a represents the original native HBV of Brazil. The phylogeographic patterns suggested a north-to-south flow of HBV/F2a from Venezuela to Brazil, whereas HBV/F1b and HBV/F4 strains appeared to have spread from Argentina to Brazil.
This study suggests a plausible route of introduction of HBV/F subgenotypes in Brazil and demonstrates the usefulness of recently developed computational tools for investigating the evolutionary history of HBV.
[show abstract][hide abstract] ABSTRACT: Little is known about the role of chemokines/chemokines receptors on T cells in natural DENV infection. Patients from DENV-2 and -3- outbreaks were studied prospectively during the acute or convalescent phases. Expression of chemokine receptor and activation markers on lymphocyte subpopulations were determined by flow cytometry analysis, plasma chemokine ligands concentrations were measured by ELISA and quantification of CCL5/RANTES(+) cells in liver tissues from fatal dengue cases was performed by immunochemistry. In the acute DENV-infection, T-helper/T-cytotoxic type-1 cell (Th1/Tc1)-related CCR5 is significantly higher expressed on both CD4 and CD8 T cells. The Th1-related CXCR3 is up-regulated among CD4 T cells and Tc2-related CCR4 is up-regulated among CD8 T cells. In the convalescent phase, all chemokine receptor or chemokine ligand expression tends to reestablish control healthy levels. Increased CCL2/MCP-1 and CCL4/MIP-1β but decreased CCL5/RANTES levels were observed in DENV-patients during acute infection. Moreover, we showed an increased CD107a expression on CCR5 or CXCR3-expressing T cells and higher expression of CD29, CD44(HIGH) and CD127(LOW) markers on CCR4-expressing CD8 T cells in DENV-patients when compared to controls. Finally, liver from dengue fatal patients showed increased number of cells expressing CCL5/RANTES in three out of four cases compared to three death from a non-dengue patient. In conclusion, both Th1-related CCR5 and CXCR3 among CD4 T cells have a potential ability to exert cytotoxicity function. Moreover, Tc1-related CCR5 and Tc2-related CCR4 among CD8 T cells have a potential ability to exert effector function and migration based on cell markers evaluated. The CCR5 expression would be promoting an enhanced T cell recruitment into liver, a hypothesis that is corroborated by the CCL5/RANTES increase detected in hepatic tissue from dengue fatal cases. The balance between protective and pathogenic immune response mediated by chemokines during dengue fever will be discussed.
PLoS ONE 01/2012; 7(7):e38527. · 3.73 Impact Factor
[show abstract][hide abstract] ABSTRACT: To estimate prevalence of hepatitis C virus (HCV) infection and identify risk factors associated and circulating HCV genotypes and subtypes.
Study conducted including 691 drug users attending 26 charitable, private and public drug treatment centers in Goiânia and Campo Grande, central-western Brazil, between 2005 and 2006. Sociodemographic characteristics and risk factors for HCV infection were collected during interviews. Blood samples were tested for HCV antibodies (anti-HCV). Positive samples were submitted to HCV RNA detection by PCR with primers complementary to 5' NC and NS5B regions of viral genome and genotyped by line probe assay (LiPA) and direct nucleotide sequencing followed by phylogenetic analysis. The prevalence and odds ratio were calculated with 95% confidence intervals. Risk factors were first estimated in the univariate analysis (p<0.10) and then analyzed by hierarchical logistic regression. Statistical significance was assessed at a 5% significance level.
The prevalence of anti-HCV was 6.9% (95% CI: 5.2-9.2). The multivariate analysis of risk factors revealed that age over 30 years and injecting drug use were associated with HCV infection. HCV RNA was detected in 85.4% (41/48) of anti-HCV-positive samples. Thirty-three samples were genotyped as genotype 1 by LiPA, subtypes 1a (63.4%) and 1b (17.1%), and 8 samples (19.5%) were genotype 3, subtype 3a. The phylogenetic analysis of the NS5B region showed that 17 (68%), 5 (20%), and 3 (12%) samples were subtypes 1a, 3a, and 1b, respectively.
The results show a high prevalence of HCV infection and predominance of subtype 1a among drug users in Brazil. In addition, injecting drug use was a major risk factor associated with HCV infection.
Revista de saude publica 09/2009; 43 Suppl 1:43-50. · 1.01 Impact Factor
[show abstract][hide abstract] ABSTRACT: Compliance with and responses to the hepatitis B vaccine were evaluated in remaining quilombo communities in Central Brazil. A total of 708 individuals who were susceptible to hepatitis B virus infection were invited to participate in the hepatitis B vaccination program in eight communities. Although 567 (80%) individuals received the first dose, only 198 (28%) complied with the full vaccination scheme. Of 148 subjects who agreed to be tested for anti-HBs, 123 (83.1%; 95%CI: 75.9-88.6) responded to the vaccine. A geometric mean titer of 512mIU/mL (95%CI: 342.5-765.3) was found. Male sex and older age were independently associated with non-response. Additional health education programs and alternative hepatitis B vaccine schedules are needed to improve the vaccination coverage in these communities in Central Brazil.
Cadernos de saúde pública / Ministério da Saúde, Fundação Oswaldo Cruz, Escola Nacional de Saúde Pública 05/2009; 25(4):738-42. · 0.83 Impact Factor
[show abstract][hide abstract] ABSTRACT: This study was conducted to estimate the prevalence and molecular epidemiological features of viral hepatitis A, B and C in the Kalunga population, which represents the largest Afro-Brazilian isolated community. Among 878 individuals studied, the overall prevalence of anti-hepatitis A virus antibodies was 80.9%, with a significant rise from 44.8% to near 100% between the first and fourth decade of life. Rates for hepatitis B surface antigen (HBsAg) and antibody to hepatitis B core antigen (anti-HBc) of 1.8% and 35.4%, respectively, were found. Increasing age, male gender, illiteracy and history of multiple sexual partners were associated with hepatitis B virus (HBV) infection. An occult HBV infection rate of 1.7% (5/295) was found among anti-HBc-positive individuals. HBV genotype A (subtype Aa) was dominant in this community. Only 5/878 individuals (0.6%) were positive for anti-hepatitis C virus (HCV). HCV RNA was detected in three of them, who were infected with genotype 1 (subtype 1a). These findings point out high, intermediate and low endemicity for hepatitis A, B and C, respectively, in the Kalunga community in Brazil. Circulation of HBV genotype A (subtype Aa) in this Afro-Brazilian isolated community indicates the introduction of this virus during the slave trade from Africa to Brazil.
Transactions of the Royal Society of Tropical Medicine and Hygiene 03/2009; 103(9):899-905. · 1.82 Impact Factor
[show abstract][hide abstract] ABSTRACT: Non-injecting drug users are at high-risk for acquiring hepatitis B virus (HBV), although the factors contributing to this increased risk are not known. In the present study, the overall and occult HBV infection prevalence rates were determined in a large population of non-injecting drug users in the Central-West region of Brazil. HBV genotypes and predictors of infection were also identified. A total of 852 individuals in 34 drug treatment centers were interviewed, and their serum samples were tested for the presence of HBV markers by ELISA. HBsAg and anti-HBc-positive samples were tested for HBV DNA by PCR. Samples with HBV DNA were genotyped by restriction fragment length polymorphism (RFLP). The overall prevalence of HBV infection was 14% (95% CI: 11.7-16.5). A multivariate analysis of risk factors showed that age >30 years, non-white race/ethnicity, duration of drug use >10 years, lifetime number of sexual partners >10, non-use of condoms, and HCV and HIV status were associated significantly with HBV infection. Of the 9 (1%) HBsAg-reactive samples, HBV DNA was present in 2/2 of HBeAg-positive and in 5/7 anti-HBe-positive samples. An occult HBV infection rate of 2.7% (3/110) was found among anti-HBc-positive individuals. All HBV DNA-positive samples were genotyped: seven were genotype A, two were genotype D, and one was genotype F. Finally, few individuals (8%) had serological evidence of a previous HBV vaccination. These findings indicate that preventive interventions are needed for both sexual and drug-related high-risk behavior. Additionally, non-injecting drug users should be targeted for HBV vaccination.
Journal of Medical Virology 03/2009; 81(4):602-9. · 2.37 Impact Factor
[show abstract][hide abstract] ABSTRACT: Hepatitis B virus (HBV) isolates have been classified in eight genotypes, A to H, which exhibit distinct geographical distributions. Genotypes A, D and F are predominant in Brazil, a country formed by a miscegenated population, where the proportion of individuals from Caucasian, Amerindian and African origins varies by region. Genotype F, which is the most divergent, is considered indigenous to the Americas. A systematic molecular characterization of HBV isolates from different parts of the world would be invaluable in establishing HBV evolutionary origins and dispersion patterns. A large-scale study is needed to map the region-by-region distribution of the HBV genotypes in Brazil.
Genotyping by PCR-RFLP of 303 HBV isolates from HBsAg-positive blood donors showed that at least two of the three genotypes, A, D, and F, co-circulate in each of the five geographic regions of Brazil. No other genotypes were identified. Overall, genotype A was most prevalent (48.5%), and most of these isolates were classified as subgenotype A1 (138/153; 90.2%). Genotype D was the most common genotype in the South (84.2%) and Central (47.6%) regions. The prevalence of genotype F was low (13%) countrywide. Nucleotide sequencing of the S gene and a phylogenetic analysis of 32 HBV genotype F isolates showed that a great majority (28/32; 87.5%) belonged to subgenotype F2, cluster II. The deduced serotype of 31 of 32 F isolates was adw4. The remaining isolate showed a leucine-to-isoleucine substitution at position 127.
The presence of genotypes A, D and F, and the absence of other genotypes in a large cohort of HBV infected individuals may reflect the ethnic origins of the Brazilian population. The high prevalence of isolates from subgenotype A1 (of African origin) indicates that the African influx during the colonial slavery period had a major impact on the circulation of HBV genotype A currently found in Brazil. Although most genotype F isolates belonged to cluster II, the presence of some isolates belonging to clusters I (subgroup Ib) and IV suggests the existence of two or more founder viral populations of genotype F in Brazil.