RESUMO
Identification of prevalent infection by hepatitis C virus (HCV) is based serologically on detecting anti-HCV immunoglobulin G, using immunoassays, immunoblot assays, and, more recently, immunochromatography-based rapid tests. None discriminate between active and resolved HCV infection. Tests for detecting HCV RNA identify active HCV infection but are costly. Serologic assays for HCV antigens have been developed and show potential for diagnosis of active HCV infection, and their performance characteristics are undergoing evaluation. The diagnosis of acute HCV infection without the demonstration of seroconversion remains elusive.
Assuntos
Hepacivirus/isolamento & purificação , Anticorpos Anti-Hepatite C/imunologia , Hepatite C/diagnóstico , RNA Viral/imunologia , Doença Aguda , Biomarcadores , Cromatografia de Afinidade/métodos , Hepacivirus/imunologia , Hepacivirus/patogenicidade , Hepatite C/imunologia , Hepatite C/virologia , Anticorpos Anti-Hepatite C/sangue , Antígenos da Hepatite C/imunologia , Humanos , Immunoblotting/métodos , Imunoglobulina G/sangue , Laboratórios , RNA Viral/análise , Sensibilidade e Especificidade , Fatores de TempoRESUMO
The Centers for Disease Control and Prevention launched the Laboratory Leadership Service (LLS) Fellowship Program in July 2015 to develop public health laboratory (PHL) leaders who will improve PHL quality and safety. This article describes a retrospective, summative evaluation to determine the extent to which LLS has met its short-term goals for PHL workforce development. The evaluation relied on existing data from routine LLS data collection and reporting, supplemented with a new alumni survey. The purpose of the design was threefold: 1) to reduce data collection burden on program staff and participants, 2) to assess the value and limits of routine fellowship data for comprehensive public health workforce development program evaluation, and 3) to identify ways to improve LLS's routine data collections for program evaluation. We used descriptive statistics, qualitative analysis, and participatory methods (i.e., a data party) to analyze and interpret data. Results show LLS short-term outcome achievement and highlight opportunities for program improvement, particularly related to the design of certain training requirements and for future evaluations. Overall, the evaluation contributes to lessons learned for PHL workforce development efforts, including how routine data collections can contribute to comprehensive public health workforce development evaluations.
Assuntos
Mão de Obra em Saúde , Liderança , Estados Unidos , Humanos , Bolsas de Estudo , Avaliação de Programas e Projetos de Saúde , Estudos Retrospectivos , Saúde Pública , Centers for Disease Control and Prevention, U.S.RESUMO
Currently available serological assays for detection of antibodies to hepatitis C virus (HCV) cannot reliably discriminate acute from chronic HCV infection. We developed a multiplexed, flow-cytometric microsphere immunoassay to measure anti-HCV-IgG reactivities to the core, NS3, NS4, and NS5 HCV recombinant proteins and applied it to 99 serum samples from 24 anti-HCV seroconverters and 141 anti-HCV-IgG and HCV RNA-positive plasma specimens from chronically infected people. Differences in the geometric means or means of signal/cutoff ratios between the two sample sets were statistically significant for all the antigens tested. A multivariate logistic regression model correctly classified the samples in two groups, with a cross-validation accuracy of 90.8% for the acute group and 97.2% for the chronic group. The immunoassay described has the potential to distinguish acute from chronic HCV infection.
Assuntos
Antígenos Virais , Técnicas de Laboratório Clínico/métodos , Anticorpos Anti-Hepatite C/sangue , Hepatite C/diagnóstico , Hepatite C/imunologia , Proteínas não Estruturais Virais , Proteínas Estruturais Virais , Citometria de Fluxo , Humanos , MicroesferasRESUMO
In this study, the prevalence rate, associated risk factors and genetic diversity of hepatitis C virus (HCV) infection were determined among people who use crack from an international drug trafficking route in Central-West, Brazil. Blood samples were collected from 700 users of crack from Campo Grande and two border cities of Mato Grosso do Sul State and tested for HCV infection using serological and molecular testing methodologies. Anti-HCV was detected in 31/700 (4.5%, 95% CI: 2.9-6.0%) and HCV RNA in 26/31 (83.9%) of anti-HCV positive samples. Phylogenetic analysis of three HCV sub-genomic regions (5'UTR, NS5B and HVR-1) revealed the circulation of 1a (73.9%), 1b (8.7%) and 3a (17.4%) genotypes. Next-generation sequencing and phylogenetic analysis of intra-host viral populations of HCV HVR-1 showed a significant variation in intra-host genetic diversity among infected individuals, with 58.8% composed of more than one sub-population. Bayesian analysis estimated that the most recent common HCV ancestor for strains identified here was introduced to this region after 1975 following expansion of intravenous drug use in Brazil. Multivariate analyses showed that only 'ever having injected drugs' was independently associated with HCV infection. These results indicate an increasing spread of multiple HCV strains requiring public health intervention, such as harm reduction, testing services and treatment among crack users in this important border region of Central Brazil.
Assuntos
Cocaína Crack , Tráfico de Drogas/estatística & dados numéricos , Hepacivirus/genética , Anticorpos Anti-Hepatite C/sangue , Hepatite C/epidemiologia , RNA Viral/genética , Abuso de Substâncias por Via Intravenosa/sangue , Adulto , Brasil/epidemiologia , Estudos Transversais , Feminino , Variação Genética , Genótipo , Humanos , Masculino , Epidemiologia Molecular , Filogenia , Prevalência , Abuso de Substâncias por Via Intravenosa/epidemiologia , Adulto JovemRESUMO
The diagnosis of recent HCV infection remains challenging due to the absence of serological markers specific to the early phase of infection. Clinical follow-up and seroconversion to anti-HCV immunoglobulin (Ig)G, detection of viral RNA and changes in levels of blood biomarkers associated with liver pathology provide circumstantial evidence of recent HCV infection. Studies based on anti-HCV IgG avidity, antigen-specific antibody profiling, HCV viral load fluctuations and signature changes in the HCV genome show potential to discriminate recent from persistent HCV infection. These markers require further evaluation and would necessitate use of samples from infected people originating from broad clinical and epidemiological contexts.
Assuntos
Genoma Viral/genética , Hepacivirus/isolamento & purificação , Anticorpos Anti-Hepatite C/sangue , Hepatite C/diagnóstico , Imunoglobulina G/sangue , RNA Viral/sangue , Afinidade de Anticorpos , Biomarcadores/sangue , Diagnóstico Precoce , Hepacivirus/genética , Hepacivirus/imunologia , Hepatite C/virologia , Humanos , Mutação , RNA Viral/genéticaRESUMO
OBJECTIVE: We have reexamined hepatitis B virus subtypes to determine the role of specific HBsAg amino acids in serologic reactivity because of problematic genotype/subtype associations seen in a set of geographically diverse serum specimens. METHODS: We obtained DNA sequences for 491 HBsAg-positive specimens from geographically distinct locations, determined their genotypes through phylogenetic analysis, and subtyped the specimens using an algorithm derived from published data on the molecular basis of HBsAg subtype reactivity. Problematic samples were subtyped serologically to resolve conflicts based on the amino acid sequence alone. RESULTS: Three isolates were found to have unusual genotype/subtype associations. Examination of the isolates' amino acid sequences suggested amino acid positions 122, 127, 140, 159 and 160 can be used to determine subtype reactivity from HBsAg amino acid sequences, while position 134, previously thought to play a role, is no longer important. CONCLUSIONS: This re-examination of hepatitis B virus subtypes shows the involvement of amino acid positions 122, 127, 140, 159 and 160 in HBsAg reactivity. While d, y, and r reactivities are controlled by single amino acid changes, w reactivity is determined by positions 122, 127, 140, and 159.
Assuntos
Algoritmos , Antígenos de Superfície da Hepatite B/química , Vírus da Hepatite B/classificação , Vírus da Hepatite B/genética , Sequência de Aminoácidos , Anticorpos Monoclonais/imunologia , Genótipo , Hepatite B/virologia , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Dados de Sequência Molecular , Alinhamento de Sequência , SorotipagemRESUMO
Seqüências de DNA de adenovirus são freqüentemente encontradas em linfócitos humanos, tendo sido utilizadas para tal as técnicas de PCR e "Southern blot". Isto é possível apesar dessas células não serem permissivas à replicação de adenovírus, sugerindo persistência do genoma viral. Para investigar esse fenômeno, procuramos detectar em voluntários não sintomáticos DNA adenoviral e expressão do gene E1A. Amostras de DNA obtidas de glóbulos brancos periféricos de 51 voluntários, foram submetidas à PCR utilizando oligonucleotídeos para uma seqüência conservada do gene hexon, seguindo-se uma "nested PCR". Seqüências de adenovirus foram encontradas em 27 amostras (52,9 per center). Depois de mais de um ano, novas amostras desses voluntários positivos foram analisadas e em 70,8 per center dos casos o resultado foi mantido. Como isto poderia ser devido à persistência, decidimos verificar se o gene precoce E1A estava relacionado analisando sua expressão através de RT-PCR. Os resultados foram negativos para todas as amostras. O par de oligonucleotídeos desenvolvido para essa finalidade, que tem como alvo uma região conservada em E1A, permitiu detectar seqüências de adenovírus diretamente por PCR. A concordância encontrada entre essa análise e a pesquisa para o gene hexon foi de 84 per center. Nossos dados sugerem alta ocorrência e persistência de genoma adenoviral em linfócitos humanos, e indicam que uma região distinta de E1A é responsável pela persistência. Podemos também afirmar que a PCR para o gene E1A é uma boa opção quando se quer detectar adenovírus, evitando-se o alto risco de contaminação da "nested PCR" necessária para identificar a presença do gene hexon.