Aspectos generales sobre la estructura del coronavirus del síndrome respiratorio agudo grave 2 (SARS-CoV-2) / General aspects about the structure of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2)

Introduction: In late 2019, a new coronavirus named Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that causes respiratory-related illness was reported in Wuhan, China. This virus can attack human lung cells causing a disease called coronavirus disease 2019 (COVID-19), which can lead to pneumonia and acute respiratory distress syndrome. Objective: Describe the structural characteristics of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Methods: A review was written from 47 bibliographic references. Articles and information from national and international journals available in the PubMed, Scopus, Medline, SciELO databases were used. The quality, reliability and validity of the selected articles were analyzed to carry out an adequate review. Analysis-synthesis and logical deduction methods were applied. Development: An introduction to the general aspects of the structure of SARS-CoV-2 is provided by stating the characteristics of the structural and non-structural proteins encoded by the viral genome, which provides the basis for understanding viral entry mechanisms to the host cell, and may be useful to stimulate the search for novel insights and possible therapeutic targets to fight the infection. Conclusions: Knowledge of the structure of the SARS-CoV-2 virus and the characteristics of the structural and non-structural proteins provides the basis for understanding the viral mechanisms of infection and the strategies for developing effective therapeutics(AU)

Introducción: A finales de 2019 se informó el brote de un nuevo coronavirus en Wuhan, China, llamado Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) que causa alteraciones en el aparato respiratorio. Este virus puede atacar las células humanas del pulmón causando una enfermedad denominada enfermedad por coronavirus 2019 (COVID-19), que puede producir neumonía y un síndrome de dificultad respiratoria aguda. Objetivo: Describir las características estructurales del virus SARS-CoV-2. Métodos: Se realizó una revisión bibliográfica a partir de 47 referencias. Se utilizaron artículos e información de revistas nacionales e internacionales disponibles en las bases de datos PubMed, Scopus, Medline, SciELO. Para llevar a cabo una revisión adecuada, se analizaron la calidad, fiabilidad y validez de los artículos seleccionados. Se aplicaron métodos de análisis-síntesis y deducción lógica. Desarrollo: Se proporciona una introducción de los aspectos generales de la estructura del SARS-CoV-2. Se enuncian las características de las proteínas estructurales y no estructurales codificadas por el genoma viral, lo que provee la base para comprender los mecanismos virales de entrada a la célula huésped. El artículo resulta de utilidad para estimular la búsqueda de nuevos conocimientos y posibles objetivos terapéuticos para combatir la infección. Conclusiones: El conocimiento sobre la estructura del virus SARS-CoV-2 y las características de las proteínas estructurales y no estructurales que lo forman ampara significativamente las bases para entender los mecanismos virales de la infección y las estrategias para el desarrollo terapéutico efectivo(AU)

Virus chikungunya: Características virales y evolución genética / Chikungunya Virus: Viral Features and Genetic Evolution

Resumen El virus chikungunya pertenece al género Alphavirus, de la familia de los Togaviridae. Es transmitido por artrópodos, en particular por la picada de especies de mosquitos, tales como Aedes aegypti y Aedes albopictus. El curso clínico característico de la infección incluye fiebres, artralgias y exantema. Desde que fue reportado en 1952 en los límites de Tanzania y Mozambique ha generado brotes de enorme significado epidemiológico. Recientemente fue causado un brote en las Américas por una cepa del virus, aparentemente, asiática. En esta revisión presentamos su filogenia, estructura y organización del genoma. Enfatizaremos en el mecanismo de multiplicación y la expresión genética. Finalmente, la interacción virus-huésped y sus mecanismos de adaptación a vectores específicos también son discutidos.

Abstract Chikungunya virus belongs to the Alphavirus genus of the family Togaviridae. It is transmitted by arthropods, in particular by the biting of mosquito species such as Aedes aegypti and Aedes albopictus. The characteristic clinical course of the infection includes fever, arthralgia, and rash. Since it was reported on 1952 on the borders of Tanzania and Mozambique, it has been triggered outbreaks with tremendous epidemiological significance. Recently an outbreak was caused in the Americas by an apparent Asian strain of this virus. In this review we present its phylogeny, structure and genome organization. We will emphasize the mechanism of replication and gene expression. Finally, the virus-host interaction and its mechanisms of adaptation to specific vectors are also discussed.

Actualización sobre fiebres hemorrágicas virales / Updating on viral hemorrhagic fevers

Fundamento: en el mundo emergen nuevos brotes de fiebres hemorrágicas virales, al mismo tiempo que antiguos brotes resurgen. Objetivo: facilitar información a estudiantes y trabajadores de la salud. Métodos: se realizó una búsqueda bibliográfica en la red Infomed en las bases de datos EBSCO, PUBMED y SCIELO con los descriptores fiebres hemorrágicas virales y viral hemorrhagic fever. Desarrollo: se caracterizó este grupo de enfermedades en su conjunto, se analizaron las coincidencias y las medidas generales para prevención y control. Conclusiones: es una información útil para el profesional y estudiante de la salud, pues coinciden en la utilización de métodos participativos de equipos transdisciplinarios, la generación de bases de datos confiables y efectivas, la diversificación de métodos analíticos y la necesidad de preparación del personal de salud para enfrentar los brotes epidémicos.

Background: outbreaks of viral hemorrhagic fevers are emerging and reemerging around the world. Objective: to provide information for health workers and students. Methods: a bibliographic search was made in Infomed (in the data bases EBSCO, PUBMED and SciELO) with the descriptors fiebres hemorrágicas virales and viral hemorrhagic fevers. Development: this group of diseases was characterized as a whole. The coincidences and general measures for control and prevention were analyzed. Conclusions: this paper is condensed and useful information for health professionals and students since there are coincidences in the use of participatory methods of transdisciplinary teams, in the generation of reliable and effective data bases, in the diversification of analytical methods and in the necessity of preparing the health staff to face these epidemic outbreaks.

Identificação do gene EBER1 e EBNA1 do vírus de Epstein Barr (EBV) em tecidos de pacientes com doença de Hodgkin na região Norte do Brasil / Identification of gene EBER1 and EBNA 1 of Epstein Barr virus (EBV) in tissues of patients with Hodgkin’s disease in Northern Brazil

O vírus de Epstein Barr (EBV) é o agente causador da mononucle¬ose infecciosa e está associado a várias desordens proliferativas malignas tais como: linfoma de Burkitt, linfoma de Hodgkin e lin¬fomas não Hodgkin. Objetivo: detectar o genoma do EBV mediante a identificação dos genes EBER1 e EBNA1 em casos de doença de Hodgkin. Métodos: um total de 65 casos de linfomas diagnosti¬cados no Hospital Ophir Loyola no período de 1996 e 2005 foram analisados no Instituto Evandro Chagas, Ananindeua, Brasil. Todos os espécimes parafinizados foram analisados por hibridização in situ (gene EBER1) e PCR em tempo real (EBNA1). Resultados: do total, 64,6% (42/65) dos pacientes eram do sexo masculino e 35,4% (23/65) do sexo feminino. O EBV foi identificado por HIS nas células Reed Sternberg e variantes em 76,9% (50/65) dos casos com idade média de 28,3 anos (variação 2-84 anos). Os subtipos histológicos de casos EBV-positivos foram os seguintes: esclerose nodular em 50% (25/50), celularidade mista em 28% (14/50), depleção linfocitária em 14% (7/50) e predominância linfocitária em 8% (4/50). O DNA do EBV foi detectado em 53% (26/49) dos casos de doença de Hodgkin com um coeficiente de regressão para a curva padrão de 0,99. Conclusão: este estudo foi a primeira descrição do vírus de Epstein Barr em casos de linfoma de Hodgkin na Amazônia Brasileira, reforçando a hipótese de que o EBV seja um co-fator no processo de transformação neoplásica em conjunto com a predisposição genética e imunidade do paciente

Introduction: EBV is the causative agent of infectious mononucleosis and is associated with several malignant proliferative disorders such as Burkitt’s lymphoma, Hodgkin’s lymphoma, some B and T cell non-Hodgkin’s lymphomas. Objective: The main objective of the study was to determine the prevalence of EBER 1 gene and EBNA1 gene in cases of Hodgkin’s disease. Material and Methods: A total of 65 cases of lymphomas diagnosed between 1996 and 2005 were obtained from “Instituto Ofir Loyola” and analyzed at the “Instituto Evandro Chagas” Ananindeua, Brazil. The EBV antigens using EBER 1 probe in situ hybridization (HIS) and real time quantitative PCR. Results: From the total obtained, 64.6% (42/65) were male and 35.4% (23/65) female. EBV was identified in the Reed- Sternberg cells and variants in 76.9% (50/65) of Hodgkin’s disease cases, the median age were 28.3 years (range 2-84). The histologic subtypes of EBV-positive cases were as follows: nodular sclerosis in 50% (25/50), mixed cellularity in 28% (14/50), lymphocyte depletion in 14% (7/50) and lymphocyte predominance in 8% (4/50). We detected EBV DNA in 53% (26/49) with a coefficient of regression for the standard curve of a minimum of 0.99. Conclusion: These results were the first demonstration of the role of Epstein Barr virus in cases of Hodgkin diseases in northern Brazil and are consistent with the hypothesis that the presence of EBV during neoplasic transformation could be an additional cofactor acting together with both genetic predisposition and immunity of the patient

Alta prevalência do genótipo 1 em portadores de hepatite C crônica em Belo Horizonte, MG / High prevalence of genotype 1 in individuals with hepatitis C in Belo Horizonte, MG

O vírus da hepatite C é caracterizado pela significativa heterogeneidade genética e é atualmente classificado em seis genótipos principais e diversos subtipos. A determinação do genótipo do vírus tem importância na prática clínica para orientar o tratamento dos pacientes portadores de hepatite C crônica. A prevalência dos diferentes genótipos e subtipos do vírus da hepatite C não tem sido amplamente estudada em algumas regiões do Brasil. Neste estudo foram analisadas 788 amostras de pacientes portadores de hepatite C crônica atendidos nos Centros de Referência em Hepatites Virais de Belo Horizonte, entre 2002 e 2006. A genotipagem do vírus foi realizada por seqüenciamento direto da região 5’ UTR. Adicionalmente, foi realizada análise filogenética incluindo todas as variantes genotípicas obtidas. Observou-se alta prevalência do genótipo 1 (78,4 por cento; 1b [40,4 por cento], 1a [37,5 por cento] e 1a/b [0,5 por cento]), seguida pelo genótipo 3a (17,9 por cento) e pelo 2b (3,1 por cento). Foram identificadas três amostras (0,4 por cento) com o genótipo 2a/c e duas amostras (0,2 por cento) com o genótipo 4. A análise filogenética mostrou a segregação esperada das seqüências obtidas junto às seqüências de referência para os genótipos 1, 2, 3 e 4, exceto em duas amostras do genótipo 1a. A alta prevalência do genótipo 1 (78,4 por cento), encontrada na população de Belo Horizonte é semelhante à previamente descrita em outras cidades, como Rio de Janeiro, mas superior à encontrada em São Paulo e no Sul do país. A presença de raras seqüências atípicas da região 5’UTR sugere a presença de variantes do vírus da hepatite C nesta população.

The hepatitis C virus is characterized by significant genetic heterogeneity. It is currently classified into six main genotypes and several subtypes. Determining the genotype of the virus is important in clinical practice for guiding the treatment for individuals with chronic hepatitis C. The prevalence of different genotypes and subtypes of the hepatitis C virus has not been fully studied in some regions of Brazil. In this study, 788 samples from patients with chronic hepatitis C who were attended at the Viral Hepatitis Reference Centers in Belo Horizonte were analyzed between 2002 and 2006. The genotyping of the virus was performed by direct sequencing of the 5’ UTR region. Additionally, phylogenetic analysis was performed, including all of the genotypic variants obtained. High prevalence of genotype 1 (78.4 percent; 1b [40.4 percent], 1a [37.5 percent] and 1a/b [0.5 percent]) was observed, followed by genotypes 3a (17.9 percent) and 2b (3.1 percent). Three samples were identified as genotype 2a/c (0.4 percent) and two as genotype 4 (0.2 percent). The phylogenetic analysis showed the expected segregation of the sequences obtained, with regard to the reference sequences for genotypes 1, 2, 3 and 4, except for two samples of genotype 1a. The high prevalence of genotype 1 (78.4 percent) found in this population from Belo Horizonte was similar to previous reports from other cities such as Rio de Janeiro, but it was higher than what has been described in São Paulo and in the south of the country. The presence of rare atypical sequences from the 5’ UTR region suggests that variants in the hepatitis C virus exist in this population.

Dengue viruses in Brazil, 1986-2006 / Virus del dengue en Brasil, 1986­2006

A total of 4 243 049 dengue cases have been reported in Brazil between 1981 and 2006, including 5 817 cases of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) and a total of 338 fatal cases. Although all Brazilian regions have been affected, the Northeast and Southeast regions have registered the highest number of notifications. DENV-1 and DENV-4 were isolated for the first time in the Amazon region of Brazil in 1981 and 1982. The disease became a nationwide public health problem following outbreaks of DENV-1 and DENV-2 in the state of Rio de Janeiro in 1986 and 1990, respectively. The introduction of DENV-3 in 2000, also in the state of Rio de Janeiro, led to a severe epidemic with 288 245 reported dengue cases, including 91 deaths. Virus strains that were typed during the 2002 epidemic show that DENV-3 has displaced other dengue virus serotypes and entered new areas, a finding that warrants closer evaluation. Unusual clinical symptoms, including central nervous system involvement, have been observed in dengue patients in at least three regions of the country.

En Brasil se han notificado 4 243 049 casos de dengue entre 1981 y 2006, de ellos 5 817 casos de dengue hemorrágico/síndrome de choque por dengue (DH/SCD) y un total de 338 casos mortales. A pesar de que la enfermedad ha afectado a todas las regiones brasileñas, el mayor número de casos se ha notificado en las regiones nororiental y suroriental. Los virus del dengue (DENV) 1 y 4 se aislaron por primera vez en la región amazónica de Brasil en 1981 y 1982. La enfermedad se convirtió en un problema nacional de salud pública después de los brotes de DENV-1 y DENV-2 en el Estado de Río de Janeiro en 1986 y 1990, respectivamente. La introducción del DENV-3 en 2000, también en el Estado de Río de Janeiro, llevó a una grave epidemia con 288 245 casos notificados de dengue y 91 muertes. Las cepas del virus identificadas durante la epidemia de 2002 demostraron que el DENV-3 ha desplazado a los otros serotipos y se ha expandido a nuevas zonas, algo que merece una evaluación más profunda. En los pacientes con dengue de al menos tres regiones del país se han observado síntomas clínicos atípicos, entre ellos alteraciones del sistema nervioso central.

Detecção de roteiros e adenovírus na Grande São Paulo no período 1984-1986: estudo eletroforético do genoma dos rotavírus / Rotavirus and adenovirus detection in the Greater Säo Paulo in 1984-1986: eletrophoretic study of the rotavirus genome

No período de 1984 a 1986, 285 amostras de fezes de crianças com sintomatologia diarreica foram submetidas às provas diagnósticas de ensaio imunoenzimático, eletroforese em gel de poliacrilamida e microscopia eletrônica. Destas amostras, 15,4% foram positivas para rotavírus e 3,2% para adenovírus. Das 44 (15,4%) amostras positivas para rotavírus pelo método imunoenzimático, 37 apresentaram perfil eletroforético do RNA característico dos rotavírus. Destas últimas, 27 foram analisadas segundo o esquema de Lourenço et alii, 1981, tendo sido verificada grande heterogeneidade de perfis e predominância dos rota vírus do subgrupo 1 foi detectada (AU).