Prevalence of infection with hantavirus in rodent populations of central Argentina

We studied hantavirus seroprevalence and virus variability in rodent populations in Diego Gaynor, northwest of Buenos Aires province, Argentina. Rodent samplings were conducted in railroads and cropfield borders in March and July 1999, September and December 2000, and March 2001. Antibody detection was performed by an enzyme link immunosorbent assay (ELISA), using the recombinant nucleoprotein of Andes (AND) virus as antigen. Tissue samples were taken from positive antibody individuals in order to confirm the presence of hantavirus genomic material and to identify virus genotypes. Akodon azarae was the most abundant species, followed by Oligoryzomys flavescens, while Calomys laucha and C. musculinus were rarely caught. We found a rate of seroprevalence of 9.3% for a total sample of 291 A. azarae and 13.5% for 37 O. flavescens. After molecular analyses of hantavirus, we confirmed the presence of hantavirus genomic material in 16 individuals with ELISA (+) results and two individuals with ELISA (-). Four amplimers for each species were sequenced and compared to the corresponding sequences of representative hantaviruses. We identified the AND Cent Lec from three O. flavescens, and the Pergamino virus from four A. azarae and from one O. flavescens. A. azarae males had higher seroprevalence than females, and heavier individuals showed higher seroprevalence than lighter ones. We did not find seroprevalence differences according to sex in O. flavescens, although this result may have been produced by the low sample size. The lowest seroprevalence was found in a period of high rodent density, when juveniles prevailed in the population. We found higher seroprevalences than those detected in previous studies for other localities of central Argentina where cases of hantavirus pulmonary syndrome (HPS) have been reported. The presence of AND Cent Lec virus in rodent populations of the study area, which is responsible of HPS cases in central Argentina, suggests that human populations are at risk of HPS disease, although there were not reported cases of this disease until today.

Molecular epidemiology of type 1 and 2 dengue viruses in Brazil from 1988 to 2001

Dengue is a mosquito-borne viral infection that in recent decades has become a major international public health concern. Epidemic dengue fever reemerged in Brazil in 1981. Since 1990 more than one dengue virus serotype has been circulating in this tropical country and increasing rates of dengue hemorrhagic fever and dengue shock syndrome have been detected every year. Some evidence supports the association between the introduction of a new serotype and/or genotype in a region and the appearance of dengue hemorrhagic fever. In order to study the evolutionary relationships and possible detection of the introduction of new dengue virus genotypes in Brazil in the last years, we analyzed partial nucleotide sequences of 52 Brazilian samples of both dengue type 1 and dengue type 2 isolated from 1988 to 2001 from highly endemic regions. A 240-nucleotide-long sequence from the envelope/nonstructural protein 1 gene junction was used for phylogenetic analysis. After comparing the nucleotide sequences originally obtained in this study to those previously studied by others, and analyzing the phylogenetic trees, we conclude that, after the initial introduction of the currently circulating dengue-1 and dengue-2 genotypes in Brazil, there has been no evidence of introduction of new genotypes since 1988. The increasing number of dengue hemorrhagic fever cases seen in Brazil in the last years is probably associated with secondary infections or with the introduction of new serotypes but not with the introduction of new genotypes.

Molecular characterization of human polyomavirus JC in Brazilian AIDS patients with and without progressive multifocal leukoencephalopathy

Background: JC virus (JCV), the causative agent of progressive multifocal leukoencephalopathy (PML), is classified in 8 different genotypes. Previous reports have suggested a positive association between specific genotypes and PML. Objective: To compare genotypes and adaptive mutations of JCV strains from Brazilian AIDS patients with and without PML. Study design: The VP1 region of JCV was amplified by polymerase chain reaction from cerebrospinal fluid samples from 51 patients with PML and from urine samples of 47 patients with AIDS without central nervous system disease. Genotyping was done by phylogenetic analysis. Amino acid replacement and selection pressures were also investigated. Results: JCV genotype frequency distributions showed that genotypes 2 (32.7%), 1 (26.5%) and 3 (23.5%) were the most prevalent. Genotype 1 had a positive association (p < 0.0001) and genotype 3 showed an inverse association (p < 0.001) with PML. A previously undescribed point mutation at residue 91 (L/I or L/V) and (L/P), non-genotype-associated, was found in 5/49 (10.2%) and 2/47 (4.3%) JCV sequences from PML and non-PML patients, respectively. This mutation was under positive selection only in PML patients. A previously described substitution of T-A in position 128 showed a significant difference between PML and non-PML cases (70% versus 16%, respectively, p < 0.0005). Conclusion: In Brazilian patients with AIDS, JCV genotype 1 showed a strong association with PML (p < 0.0001) and JCV genotype 3 showed an inverse association with PML. The possible association of aminoacids substitution in residues 91 and 128 with PML in patients with AIDS must be further investigated. (C) 2010 Elsevier B.V. All rights reserved.

Comparação dos testes de virusneutralização contra os genótipos 1 e 2 do vírus da diarreia viral bovina (BVDV-1 e BVDV-2) em bovinos de rebanhos naturalmente infectados

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Diarréia viral bovina(BVD): aspectos epidemiológicos da infecção persistente, avaliação sorológica da resposta imune e caracterização molecular do virús

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Vírus da Hepatite C: prevalência dos genótipos, fatores de risco, alterações bioquímicas e histopatológicas de pacientes atendidos no Núcleo de Medicina Tropical

A hepatite causada pelo HCV constitui-se de uma doença silenciosa que tende a evoluir para a forma crônica. A persistência viral, fatores genéticos do indivíduo e do vírus (genótipos), estilo de vida e exposição a fatores de risco aumentam as chances de o portador desenvolver carcinoma hepatocelular. Este estudo teve como objetivo verificar a função hepática dos pacientes com hepatite C; avaliar os fatores de riscos para aquisição do vírus; determinar os genótipos de HCV mais prevalentes e correlacionar os genótipos com os achados histopatológicos das biópsias hepáticas. A amostra constituiu-se de 152 pacientes adultos com sorologia (ELISA) reagente para anticorpos anti-HCV, que aceitaram participar da pesquisa, colheram amostra sanguínea para as análises e responderam a um questionário epidemiológico. A análise epidemiológica demonstrou maioria do sexo masculino, faixa etária de 45 anos e predomínio de indivíduos casados ou com união estável. Quanto aos fatores de risco para aquisição da infecção, observou-se a multiplicidade de parceiros, o não uso de preservativos, internações hospitalares e o compartilhamento de kits de manicure. Na detecção do RNA viral, 107 (70,4%) apresentaram positividade, sendo 97 (90,6%) do genótipo 1 e 10 (9,4%) do genótipo 3. Não houve variação entre as dosagens bioquímicas, os genótipos e as alterações histopatológicas. Dos 65 pacientes que realizaram biópsia hepática e exame histopatológico, todos os pacientes tinham hepatite crônica. Analisando as alterações histopatológicas e os genótipos virais encontramos associação destas variáveis, sendo o genótipo 1 relacionado a modificações histológicas mais intensas. Os resultados encontrados estão em concordância com outros descritos na literatura.

Prevalência de genótipos e de mutantes pré-core A-1896 do vírus da hepatite B e suas implicações na hepatite crônica, em uma população da Amazônia oriental

A infecção pelo virus da hepatite B apresenta amplo espectro de manifestações clínicas. Objetivando conhecer os genótipos do HBV mais prevalentes e determinar a ocorrência da mutação pré-core A-1896, em uma população da Amazônia oriental, correlacionando com o diagnóstico clínico, foram selecionados 51 pacientes portadores crônicos de HBsAg e HBV-DNA positivos e divididos em três grupos: grupo A (n=14, pacientes assintomáticos); grupo B (n=20, sintomáticos HBeAg positivos) e grupo C (n=17, sintomáticos HBeAg negativos), sendo usado o sequenciador automático ABI modelo 377 para identificação de genótipos e mutantes pré-core. Os resultados evidenciaram o genótipo A como o mais prevalente, 81,8%, 89,5% e 93,7%, nos grupos A, B e C, respectivamente. A mutação pré-core A-1896 foi encontrada em 11,5% (3/26), sendo todos assintomáticos. Concluiu-se que na população estudada o genótipo A foi o mais prevalente e houve baixa ocorrência do mutante pré-core A-1896, ambos não se constituindo fatores agravantes da doença hepática.

Pesquisa e genotipagem do vírus da hepatite C em portadores de doenças renais crônicas submetidos à hemodiálise

Pacientes com doença renal crônica tem alto risco de adquirir o vírus da hepatite C (VHC). A prevalência de hepatite C em unidades de hemodiálise é elevada. O estudo teve por objetivo avaliar a presença do VHC e seus diferentes genótipos em portadores de doença renal crônica que realizaram hemodiálise em Belém e região metropolitana, no Estado do Pará, Brasil, determinando a prevalência do vírus, genótipos e as características epidemiológicas dos portadores da doença renal crônica. Foi realizado um estudo transversal, em sete unidades de hemodiálise das cidades de Belém e região metropolitana, no período de outubro de 2011 a abril de 2012. Foi aplicado um questionário com dados sociais, epidemiológicos e sobre a presença de fatores de risco para hepatites virais. Material biológico foi coletado dos pacientes para os exames ELISA e PCR VHC. Os pacientes com presença de RNA viral foram avaliados quanto aos genótipos. A prevalência dos anticorpos para VHC entre os indivíduos estudados foi de 8,4%, enquanto 5,4% apresentaram RNA viral, com 0,1% entre os não reagentes. O genótipo 1 foi o mais prevalente, com 86,1%, seguido do tipo 2, com 11,6%. O tipo 3 teve somente 2,3%. A análise epidemiológica mostrou predomínio do sexo masculino, faixa etária de 49 anos, casados ou em união estável, com baixo nível de escolaridade e renda familiar de até 2 salários mínimos. A principal causa da doença renal crônica foi o diabetes mellitus (34,4%), seguida de glomerulonefrites (18,6%) e hipertensão arterial (17,1%). O tempo de hemodiálise foi significativamente importante fator de risco para aquisição do VHC (p=0,012), com a maioria dos portadores do VHC que adquiriram a doença durante hemodiálise estava acima de 5 anos de tratamento (p= 0,0001). Outro fator de risco associado ao VHC foi transplante de órgão prévio. Conclui-se que, em Belém e região metropolitana, a prevalência de VHC em hemodiálise foi elevada e o genótipo mais frequente é o mesmo da população geral no norte do Brasil.

Distribution of hepatitis c virus (hcv) genotypes in patients with chronic infection from Rondonia, Brazil

Background: Hepatitis C virus (HCV) is an important human pathogen affecting around 3% of the human population. In Brazil, it is estimated that there are approximately 2 to 3 million HCV chronic carriers. There are few reports of HCV prevalence in Rondonia State (RO), but it was estimated in 9.7% from 1999 to 2005. The aim of this study was to characterize HCV genotypes in 58 chronic HCV infected patients from Porto Velho, Rondonia (RO), Brazil. Methods: A fragment of 380 bp of NS5B region was amplified by nested PCR for genotyping analysis. Viral sequences were characterized by phylogenetic analysis using reference sequences obtained from the GenBank (n = 173). Sequences were aligned using Muscle software and edited in the SE-AL software. Phylogenetic analyses were conducted using Bayesian Markov chain Monte Carlo simulation (MCMC) to obtain the MCC tree using BEAST v. 1.5.3. Results: From 58 anti-HCV positive samples, 22 were positive to the NS5B fragment and successfully sequenced. Genotype 1b was the most prevalent in this population (50%), followed by 1a (27.2%), 2b (13.6%) and 3a (9.0%). Conclusions: This study is the first report of HCV genotypes from Rondonia State and subtype 1b was found to be the most prevalent. This subtype is mostly found among people who have a previous history of blood transfusion but more detailed studies with a larger number of patients are necessary to understand the HCV dynamics in the population of Rondonia State, Brazil.

Characterization of Hepatitis B virus (HBV) genotypes in patients from Rondonia, Brazil

Background: Hepatitis B virus (HBV) can be classified into nine genotypes (A-I) defined by sequence divergence of more than 8% based on the complete genome. This study aims to identify the genotypic distribution of HBV in 40 HBsAg-positive patients from Rondonia, Brazil. A fragment of 1306 bp partially comprising surface and polymerase overlapping genes was amplified by PCR. Amplified DNA was purified and sequenced. Amplified DNA was purified and sequenced on an ABI PRISM (R) 377 Automatic Sequencer (Applied Biosystems, Foster City, CA, USA). The obtained sequences were aligned with reference sequences obtained from the GenBank using Clustal X software and then edited with Se-Al software. Phylogenetic analyses were conducted by the Markov Chain Monte Carlo (MCMC) approach using BEAST v.1.5.3. Results: The subgenotypes distribution was A1 (37.1%), D3 (22.8%), F2a (20.0%), D4 (17.1%) and D2 (2.8%). Conclusions: These results for the first HBV genotypic characterization in Rondonia state are consistent with other studies in Brazil, showing the presence of several HBV genotypes that reflects the mixed origin of the population, involving descendants from Native Americans, Europeans, and Africans.

Chronic hepatitis C virus infections in Brazilian patients: association with genotypes, clinical parameters and response to long term alpha interferon therapy

The present study assessed the clinical significance of hepatitis C virus (HCV) genotypes and their influence on response to long term recombinant-interferon-alpha (r-IFN-a) therapy in Brazilian patients. One hundred and thirty samples from patients previously genotyped for the HCV and with histologically confirmed chronic hepatitis C (CH-C) were evaluated for clinical and epidemiological parameters (sex, age, time of HCV infection and transmission routes). No difference in disease activity, sex, age or mode and time of transmission were seen among patients infected with HCV types 1, 2 or 3. One hundred and thirteen of them were treated with 3 million units of r-IFN-a, 3 times a week for 12 months. Initial response (IR) was significantly better in patients with genotype 2 (100%) and 3 (46%) infections than in patients with genotype 1 (29%) (p < 0.005). Among subtypes, difference in IR was observed between 1b and 2 (p < 0.005), and between 1b and 3a (p < 0.05). Sustained response (SR) was observed in 12% for (sub)type 1a, 13% for 1b, 19% for 3a, and 40% for type 2; significant differences were found between 1b and 2 (p < 0.001), and between 1b and 3a (p < 0.05). Moreover, presence of cirrhosis was significantly associated with non response and response with relapse (p < 0.05). In conclusion, non-1 HCV genotype and lack of histological diagnosis of cirrhosis were the only baseline features associated with sustained response to treatment. These data indicate that HCV genotyping may have prognostic relevance in the responsiveness to r-IFN-a therapy in Brazilian patients with chronic HCV infection, as seen in other reports worldwide.

A real-time quantitative assay for hepatitis B DNA virus (HBV) developed to detect all HBV genotypes

Hepatitis B virus (HBV) is a major cause of chronic liver disease worldwide. Besides genotype, quantitative analysis of HBV infection is extensively used for monitoring disease progression and treatment. Affordable viral load monitoring is desirable in resource-limited settings and it has been already shown to be useful in developing countries for other viruses such as Hepatitis C virus (HCV) and HIV. In this paper, we describe the validation of a real-time PCR assay for HBV DNA quantification with TaqMan chemistry and MGB probes. Primers and probes were designed using an alignment of sequences from all HBV genotypes in order to equally amplify all of them. The assay is internally controlled and was standardized with an international HBV panel. Its efficacy was evaluated comparing the results with two other methods: Versant HBV DNA Assay 3.0 (bDNA, Siemens, NY, USA) and another real-time PCR from a reference laboratory. Intra-assay and inter-assay reproducibilities were determined and the mean of CV values obtained were 0.12 and 0.09, respectively. The assay was validated with a broad dynamic range and is efficient for amplifying all HBV genotypes, providing a good option to quantify HBV DNA as a routine procedure, with a cheap and reliable protocol.

Prevalence of hepatitis C virus infection and HCV genotypes among hemophiliacs in the State of Bahia, Northeastern Brazil: analysis of serological and virological parameters

The objective of the present study was to analyze HCV serological and virological parameters from hemophiliacs in the State of Bahia. Anti-HCV was investigated by ELISA in a cohort of 268 hemophiliacs A/B who were followed-up in a reference unit for hemotherapy in the State of Bahia. HCV viremia and genotypes were also determined from a subset of 66 anti-HCV seropositive hemophiliacs. Seroprevalence among hemophiliacs was 42.2% (95% CI 36.5-48.1) and was significantly higher (p<0.05) according to age >10 years, presence of factor VIII/IX inhibitory antibodies and other infection markers. None of the hemophiliacs less than 5 years of age were anti-HCV seropositive. Viremia was detectable in 77.3% (51/66). HCV genotype 1 (74%) was the most prevalent followed by genotype 3 (22%) and genotype 2 (4%). Our results indicate that HCV prevalence is still high among hemophiliacs, although HCV transmission was not observed in young hemophiliacs.

Drug resistance and genotypes of strains of Mycobacterium tuberculosis isolated from human immunodeficiency virus-infected and non-infected tuberculosis patients in Bauru, São Paulo, Brazil

Little is known about transmission and drug resistance of tuberculosis (TB) in Bauru, State of São Paulo. The objective of this study was to evaluate risk factors for transmission of Mycobacterium tuberculosis strains in this area. Strains were collected from patients attended at ambulatory services in the region and susceptibility towards the main first line antibiotics was determined and fingerprinting performed. A total of 57 strains were submitted to susceptibility testing: 23 (42.6%) were resistant to at least one drug while 3 (13%) were resistant against both rifampicin and isoniazide. Resistant strains had been isolated from patients that had not (n = 13) or had (n = 9) previously been submitted to anti-TB treatment, demonstrating a preoccupying high level of primary resistance in the context of the study. All strains were submitted to IS6110 restriction fragment length polymorphism (IS6110-RFLP) and double repetitive element PCR (DRE-PCR). Using IS6110-RFLP, 26.3% of the strains were clustered and one cluster of 3 patients included 2 HIV-infected individuals that had been hospitalized together during 16 days; clustering of strains of patients from the hospital was however not higher than that of patients attended at health posts. According to DRE-PCR, 55.3% belonged to a cluster, confirming the larger discriminatory power of IS6110-RFLP when compared to DRE-PCR, that should therefore be used as a screening procedure only. No clinical, epidemiological or microbiological characteristics were associated with clustering so risk factors for transmission of TB could not be defined in the present study.

Hepatitis B virus infection profile in hemodialysis patients in Central Brazil: prevalence, risk factors, and genotypes

Hemodialysis patients are at high risk for hepatitis B virus (HBV) infection. A survey was conducted in the hemodialysis population of the state of Goiás, Central Brazil, aiming to assess the prevalence of HBV infection, to analyse associated risk factors, and also to investigate HBV genotypes distribution. A total of 1095 patients were interviewed in 15 dialysis units. Serum samples were screened for HBV serological markers by enzyme-linked immunosorbent assay. Hepatitis B surface antigen (HBsAg) positive samples were tested for HBV DNA by polymerase chain reaction and genotyped by restriction fragment length polymorphism. Global HBV infection prevalence was 29.8% (95% CI: 27.1-32.5). Multivariate analysis of risk factors showed that male gender, length of time on hemodialysis, and blood transfusion before 1993 were associated with HBV positivity. HBV DNA was detected in 65.4% (17/26) of the HBsAg-positive samples. Thirteen of 17 HBV DNA positive samples were genotyped. Genotype D (61.5%) was predominant, followed by A (30.8%), while genotype F was detected in only one (7.7%) sample.