Nuevos y viejos aspectos de la gripe / Old and new aspects of influenza

La gripe es una enfermedad infecciosa clásica que, a través de la continua variación que experimentan los virus que la producen, nos impone nuevos retos que debemos solventar con la mayor celeridad posible. La pandemia de COVID-19 ha modificado sustancialmente el comportamiento de la gripe y de otros virus respiratorios, y en los próximos años tendremos que convivir con un nuevo patógeno que probablemente interactuará con los existentes bajo un prisma que de momento no alcanzamos a vislumbrar. Sin embargo, los conocimientos previos a la pandemia nos permiten focalizar en los aspectos que se deben modificar para que la gripe sea un reto asumible a futuro. En esta revisión se hace hincapié en los aspectos más relevantes de la epidemiología, la carga de enfermedad, el diagnóstico y la prevención mediante vacunas, y cómo fluyen las tendencias científicas y clínicas en dichos aspectos desde lo anteriormente conocido a los retos futuros (AU)

Influenza is a classic infectious disease that, through the continuous variation of the viruses that produce it, imposes new challenges that we must solve as quickly as possible. The COVID-19 pandemic has substantially modified the behavior of influenza and other respiratory viruses, and in the coming years we will have to coexist with a new pathogen that will probably interact with existing pathogens in a way that we cannot yet glimpse. However, knowledge prior to the pandemic allows us to focus on the aspects that must be modified to make influenza an acceptable challenge for the future. In this review, emphasis is placed on the most relevant aspects of epidemiology, disease burden, diagnosis, and vaccine prevention, and how scientific and clinical trends in these aspects flow from the previously known to future challenges (AU)

Old and new aspects of influenza. / Nuevos y viejos aspectos de la gripe.

Influenza is a classic infectious disease that, through the continuous variation of the viruses that produce it, imposes new challenges that we must solve as quickly as possible. The COVID-19 pandemic has substantially modified the behavior of influenza and other respiratory viruses, and in the coming years we will have to coexist with a new pathogen that will probably interact with existing pathogens in a way that we cannot yet glimpse. However, knowledge prior to the pandemic allows us to focus on the aspects that must be modified to make influenza an acceptable challenge for the future. In this review, emphasis is placed on the most relevant aspects of epidemiology, disease burden, diagnosis, and vaccine prevention, and how scientific and clinical trends in these aspects flow from the previously known to future challenges.

Virology: syndromic diagnosis of meningitis and encephalitis. / Virología: diagnóstico sindrómico de meningitis y encefalitis.

Viral infections of the nervous system represent a major health problem. It is estimated that the incidence of viral meningitis in the general population ranges from 5-17 cases per 100,000 inhabitants per year in developed countries. This heading encompasses highly varied clinical pictures, ranging from meningitis to encephalitis. This article presents the agents involved in our environment and discusses their expressiveness. In immunocompetent patients, the course of these infections is usually benign. Nucleic acid amplification techniques are the gold standard for their etiological diagnosis. The introduction of polymerase chain reaction and serological diagnosis of the main arboviruses has increased the diagnostic capabilities in a wide spectrum of these clinical entities.

False-negative result in molecular diagnosis of SARS-CoV-2 in samples with amplification inhibitors / Resultado falso negativo no diagnóstico molecular de SARS-CoV-2 em amostras com inibidores de amplificação

ABSTRACT Introduction: Although reverse transcription-polymerase chain reaction (rRT-PCR) is the gold standard method for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), some factors, such as the presence of amplification inhibitors, lead to false-negative results. Objective: Here we describe the differences between rRT-PCR results for SARS-CoV-2 infection in normal and diluted samples, simulating the need for dilution due to the presence of amplification inhibitors. Material and method: Viral ribonucleic acid (RNA) from samples of nasopharyngeal swabs from 20 patients previously detected as "Negative" and 21 patients detected as "Positive" for SARS-CoV-2 was performed with the EasyExtract DNA-RNA kit (Interprise®). The rRT-PCR was performed with the OneStep/COVID-19 kit (IBMP), with normal and diluted (80 µl of H2O RNAse free) samples, totaling 82 tests. Results: The results indicate that there is an average variation (a < 0.05) delaying the Cq between the results of amplification of the internal control (IC), N gene (NG), and ORF1ab (OF), 1.811 Cq, 3.840 Cq, and 3.842 Cq, respectively. Discussion: The extraction kit does not completely purify the inhibitor compounds; therefore, no amplified product result may occur. In this study, we obtained a 19.04% false-negative diagnosis after sample dilution; this process reduces the efficiency of rRT-PCR to 29.8% in detecting SARS-CoV-2. Conclusion: Knowing the rRT-PCR standards of diluted samples can assist in the identification of false-negative cases and, consequently, avoid incorrect diagnosis.

RESUMEN Introducción: Aunque la reacción en cadena de la polimerasa con transcriptasa reversa en tiempo real (rRT-PCR) sea el método de referencia para detección del coronavirus tipo 2 del síndrome respiratorio agudo grave (Sars-CoV-2), algunos factores como la presencia de inhibidores de amplificación conducen a resultados falsos negativos. Objetivo: Describimos las diferencias entre los resultados de rRT-PCR para infección por Sars-CoV-2 en muestras normales y diluidas, simulando la necesidad de dilución debido a la presencia de inhibidores de amplificación. Material y método: La extracción de ácido ribonucleico (ARN) viral de muestras de hisopos nasofaríngeos de 20 pacientes previamente detectados como "negativos" y 21 pacientes detectados como "positivos" para Sars-CoV-2 se realizó con el kit Easy Extract DNA-RNA (Interprise®). La rRT-PCR se realizó con el kit OneStep/Covid-19 (IBMP), con muestras normales y diluidas (80 µl de H2O libre de ARNasa), totalizando 82 pruebas. Resultados: Los resultados indican que hay una variación media (a < 0,05) retrasando el ciclo de cuantificación (Cq) entre los resultados de amplificación del control interno (CI), gen N (GN) y ORF1ab (OF) de 1,811 Cq, 3,840 Cq y 3,842 Cq. Discusión: El kit de extracción no purifica completamente los compuestos inhibidores; por lo tanto, puede ocurrir no amplificación. Obtuvimos un diagnóstico falso negativo de 19,04% después de la dilución de la muestra; ese proceso reduce la eficiencia de la rRT-PCR hacia 29,8% en la detección de Sars-CoV-2. Conclusión: Conocer los patrones de la rRT-PCR de muestras diluidas puede ayudar en la identificación de casos falsos negativos y, por consiguiente, evitar un diagnóstico equivocado.

RESUMO Introdução: Embora a reação em cadeia da polimerase de transcrição reversa (rRT-PCR) seja o método padrão-ouro para detecção de coronavírus da síndrome respiratória aguda grave 2 (SARS-CoV-2), alguns fatores como a presença de inibidores de amplificação levam a resultados falso negativos. Objetivo: Descrevemos as diferenças entre os resultados de rRT-PCR para infecção por SARS-CoV-2 em amostras normais e diluídas, simulando a necessidade de diluição devido à presença de inibidores de amplificação. Material e método: A extração de ácido ribonucleico (RNA) viral de amostras de suabes nasofaríngeos de 20 pacientes previamente detectados como "negativos" e 21 pacientes detectados como "positivos" para SARS-CoV-2 foi realizada com kit o EasyExtract DNA-RNA (Interprise®). A rRT-PCR foi realizada com o kit OneStep/COVID-19 (IBMP), com amostras normais e diluídas (80 µl de H2O RNAse-free), totalizando 82 testes. Resultados: Os resultados indicam que existe uma variação média (a < 0,05) atrasando o Cq entre os resultados de amplificação do controle interno (CI), gene N (GN) e ORF1ab (OF) de 1,811 Cq, 3,840 Cq e 3,842 Cq, respectivamente. Discussão: O kit de extração não purifica completamente os compostos inibidores, portanto, pode ocorrer não amplificação. Obtivemos um diagnóstico falso negativo de 19,04% após a diluição da amostra; esse processo reduz a eficiência da rRT-PCR para 29,8% na detecção de SARS-CoV-2. Conclusão: Conhecer os padrões da rRT-PCR de amostras diluídas pode auxiliar na identificação de casos falso negativos e, consequentemente, evitar um diagnóstico incorreto.

[Microbiological diagnosis of emerging arboviral and rodent borne diseases]. / Diagnóstico microbiológico de arbovirosis y robovirosis emergentes.

Vector borne viruses (VBV) include viruses transmitted by arthropods, rodents and other animals. In Spain the three main autochthonous VBVs causing human diseases are: Toscana, West Nile and Lymphocytic Choriomeningitis viruses. There are also other imported viruses that are potential threats to our public health, due to the presence of competent transmission vectors (dengue and chikungunya viruses in areas infested with Aedes albopictus), or due to the potential person-to-person transmission (Lassa and other viruses causing haemorrhagic fever). The Spanish Society for Infectious Diseases and Clinical Microbiology has responded to the emergence of VBVs by publishing a special issue of Microbiological Proceedings focused on the diagnosis of those emerging vector borne viruses of major concern in our country.

Aislamientos virales en niños y adultos con infecciones respiratorias agudas / Viral isolations in children and adults with acute respiratory infections

Introducción: las infecciones respiratorias agudas constituyen un grupo de enfermedades que varían desde un catarro común hasta procesos broncopulmonares graves. Entre los agentes causales figuran los virus, los cuales se diseminan por las secreciones respiratorias. Objetivos: mostrar la positividad de aislamientos virales en niños y adultos, vivos o fallecidos, con infecciones respiratorias agudas.Métodos: se efectuó un estudio descriptivo y observacional de 364 pacientes de la provincia de Camagüey, ingresados con el diagnóstico de infecciones respiratorias agudas, desde enero de 2011 hasta diciembre de 2012. A cada enfermo se le llenó una encuesta epidemiológica y se le tomó muestra de exudado nasofaríngeo o biopsia del tejido pulmonar en el caso de los fallecidos. Estas se inocularon en medio de transporte y fueron remitidas a centros especializados para realizar el diagnóstico virológico. Resultados: del total de pacientes con positividad viral, 221 eran niños (30,3 por ciento) y 143 adultos (36,3 por ciento). Entre los virus predominantes figuraron: rinovirus, sincitial respiratorio de tipo A e influenza A (H1N1) pdm09. Conclusiones: más de la cuarta parte de los pacientes tuvieron virus respiratorios. La población infantil fue la más dañada, la de mayor letalidad y coinfecciones de rinovirus con otros virus respiratorios(AU)

Introduction: the acute respiratory infections constitute a group of diseases which vary from a common cold to serious bronchopulmonary processes. Among the causal agents there are the viruses, which are disseminated by the respiratory secretions. Objectives: to show the positivity of viral isolations in children and adults, alive or dead, with acute respiratory infections. Methods: a descriptive and observational study of 364 patients in Camagüey province admitted with the diagnosis of acute respiratory infections was carried out from January, 2011 to December, 2012. An epidemiological survey was filled and samples of nasopharyngeal exudates were taken from each sick person, or lung tissue biopsy were obtained in cases of deads. These were inoculated in transport media and they were referred to specialized centers to carry out the virological diagnosis.Results: of the total of patients with viral positivity, 221 were children (30.3 percent) and 143 adults (36.3 percent). Among the predominant viruses there were: rhinovirus, respiratory syncytial type A and influenza A (H1N1) pdm09.Conclusions: more than the fourth part of patients had respiratory virus and the child population was the most affected, with higher lethality and rhinovirus coinfections with other respiratory viruses(AU)

Aislamientos virales en niños y adultos con infecciones respiratorias agudas / Viral isolations in children and adults with acute respiratory infections

Introducción: las infecciones respiratorias agudas constituyen un grupo de enfermedades que varían desde un catarro común hasta procesos broncopulmonares graves. Entre los agentes causales figuran los virus, los cuales se diseminan por las secreciones respiratorias. Objetivos: mostrar la positividad de aislamientos virales en niños y adultos, vivos o fallecidos, con infecciones respiratorias agudas. Métodos: se efectuó un estudio descriptivo y observacional de 364 pacientes de la provincia de Camagüey, ingresados con el diagnóstico de infecciones respiratorias agudas, desde enero de 2011 hasta diciembre de 2012. A cada enfermo se le llenó una encuesta epidemiológica y se le tomó muestra de exudado nasofaríngeo o biopsia del tejido pulmonar en el caso de los fallecidos. Estas se inocularon en medio de transporte y fueron remitidas a centros especializados para realizar el diagnóstico virológico. Resultados: del total de pacientes con positividad viral, 221 eran niños (30,3 %) y 143 adultos (36,3 %). Entre los virus predominantes figuraron: rinovirus, sincitial respiratorio de tipo A e influenza A (H1N1) pdm09. Conclusiones: más de la cuarta parte de los pacientes tuvieron virus respiratorios. La población infantil fue la más dañada, la de mayor letalidad y coinfecciones de rinovirus con otros virus respiratorios.

Introduction: the acute respiratory infections constitute a group of diseases which vary from a common cold to serious bronchopulmonary processes. Among the causal agents there are the viruses, which are disseminated by the respiratory secretions. Objectives: to show the positivity of viral isolations in children and adults, alive or dead, with acute respiratory infections. Methods: a descriptive and observational study of 364 patients in Camagüey province admitted with the diagnosis of acute respiratory infections was carried out from January, 2011 to December, 2012. An epidemiological survey was filled and samples of nasopharyngeal exudates were taken from each sick person, or lung tissue biopsy were obtained in cases of deads. These were inoculated in transport media and they were referred to specialized centers to carry out the virological diagnosis. Results: of the total of patients with viral positivity, 221 were children (30.3%) and 143 adults (36.3%). Among the predominant viruses there were: rhinovirus, respiratory syncytial type A and influenza A (H1N1) pdm09. Conclusions: more than the fourth part of patients had respiratory virus and the child population was the most affected, with higher lethality and rhinovirus coinfections with other respiratory viruses.

[Microbiological diagnosis of viral respiratory infections in the adult patient]. / Diagnóstico microbiológico de las infecciones virales respiratorias en el paciente adulto.

Conventional techniques for the diagnosis of respiratory viruses are still being used, although molecular methods are now considered as a gold standard in this field. Molecular techniques have a great number of advantages such as an excellent sensitivity, specificity, adaptability to emerging viruses, capability for multiplex and for automation. With all the available repertoire of techniques for microbiological diagnosis, the knowledge relative to respiratory viruses is growing up not only for new aetiological agents but also for its epidemiology. The advances in molecular and non-molecular fast diagnostic methods for one or more respiratory viruses allow quick decisions in the management of the patient. However, there are also disadvantages. The great sensitivity of molecular techniques has meant a significant increase in the rate of multiple detections of respiratory viruses, whose clinical involvement is difficult to interpret. Finally, it remains to show whether the use of new techniques, of high cost, in the microbiological routine diagnosis of acute respiratory viral infections in the hospitalized patient, is cost effective.

Diagnóstico virológico de la infección por virus sincitial respiratorio / Virological diagnosis of respiratory syncytial virus

La enfermedad respiratoria aguda se define como un conjunto de infecciones del tracto respiratorio que pueden ser causadas por una gran variedad de microorganismos tanto virales como bacterianos, y que constituyen un importante problema de salud pública en el mundo. La infección por Virus Sincitial Respiratorio (VSR) está catalogada como una de las principales causas de enfermedad respiratoria aguda, presentándo se especialmente en niños menores de dos años. La falta de diagnóstico confiable de la etiología en las infecciones respiratorias, da como resultado un manejo inadecuado de los pacientes, lo cual puede originar varios tipos de complicaciones. Por tal razón, en esta revisión de la literatura nos enfocamos en presentar un panorama general de la situación de las infecciones respiratorias debidas a VSR en Latinoamérica y las principales dificultades que se presentan al realizar el diagnostico virológico. Para el caso puntual del VSR debido a que todos los agentes etiológicos producen signos y síntomas similares, estos no pueden ser tomados como referencia para distinguir el agente etiológico asociado, así que, en este trabajo se describen las estrategias para realizar el diagnostico de VSR como por ejemplo los que se encargan de detectar anticuerpos específicos en el suero y también los métodos de detección del virus directamente en la muestra de secreción respiratoria, es decir el aislamiento viral en cultivo celular, la detección de antígenos por fluorescencia y la detección de ácidos nucleicos.

Acute respiratory disease is defined as a set of respiratory tract infections that can be caused by a variety of both viral and bacterial microorganisms, which constitute a major public health problem in the world. Respiratory Syncytial Virus (RSV) infection is listed as a major cause of acute respiratory disease, occurring especially in children less than two years old. The lack of accurate diagnosis of respiratory infections etiology, results in an inadequate management of patients, which can cause lots of complications. Thus, this review is focused on presenting an overview of the status of respiratory infections due to RSV in Latin America and the main difficulties related with performing the virological diagnosis. For the specific case of RSV, since all etiologic agents produce similar symptoms, clinical signs cannot be taken as a reference to distinguish the etiological agent of the disease, so, in this paper we describe strategies for diagnosis of RSV such as those that detects specific antibodies in serum and also methods that directly detects the virus in the respiratory secretion sample, in other words, the viral isolation in cell culture, antigens and nucleic acid detection.