Virus de la influenza / Influenza Virus

El virus de la influenza es un importante agente patógeno humano que causa infecciones respiratorias y una considerable morbimortalidad anual a nivel mundial. El virus puede circular esporádicamente durante brotes locales como parte de una epidemia estacional o puede generar una pandemia mundial. Durante las epidemias estacionales, la mortalidad se reporta principalmente entre personas muy jóvenes y adultos mayores; la Organización Mundial de la Salud estima que cada año se presentan entre tres y cinco millones de casos de enfermedad grave y de 250.000 a 500.000 muertes en el mundo. Las pandemias de influenza se presentan cuando se produce un reordenamiento genético del virus (antigen shift) que da lugar a una variante antigénicamente novedosa para la cual no hay anticuerpos en la población. Hasta la fecha se han reportado pandemias en 1918, 1957, 1968 y 2009, las cuales causaron la muerte de 60 millones de personas, aproximadamente.

[Detection of dengue virus antigen in post-mortem tissues]. / Detección de antígenos del virus del dengue en tejidos post mórtem.

The epidemiological situation of dengue has worsened over the last decade. The difficulties in preventing its transmission and the absence of a vaccine or specific treatment have made dengue a serious risk to public health, health centers and research systems at different levels. Currently, most studies on the pathogenesis of dengue infection focus on the T-cell immune response almost exclusively in secondary infections and are aimed at identifying the mechanisms involved in the development of vascular permeability and bleeding events that accompany the infection. This report describes the case of a baby girl less than 45 days of age with clinical signs of severe dengue, whose diagnosis was confirmed by reverse transcription polymerase chain reaction in post-mortem tissue samples and by the ancillary diagnostic use of immunohistochemistry, which detected viral antigens in all organs obtained at autopsy. This case highlights the importance of studying primary infections associated with severe dengue, particularly in children, who are more likely to develop the severe form of the disease without previous infection, and it further stresses the importance of a diagnosis that should not be based solely on the examination of liver tissue samples when studying the pathogenesis of the viral infection.

Detección de antígenos del virus del dengue en tejidos post mórtem / Detection of dengue virus antigen in post-mortem tissues

El panorama epidemiológico del dengue ha empeorado durante la última década. Las dificultades para prevenir su transmisión, así como la ausencia de una vacuna o tratamiento específico, lo convierten en un riesgo que desafía las medidas de salud pública y desborda la capacidad de los centros de salud y los sistemas de investigación a muchos niveles. Actualmente, la mayoría de los estudios sobre la patogenia de la infección centran su atención en la respuesta inmunitaria de las células T casi exclusivamente en infecciones secundarias y están dirigidos a identificar los mecanismos implicados en el desarrollo de la permeabilidad vascular y de los eventos hemorrágicos que lo acompañan. En este reporte se describe el caso de una menor de 45 días de edad con signos clínicos de dengue grave, cuyo diagnóstico se confirmó por reacción en cadena de la polimerasa de transcripción inversa en muestras de tejido post mórtem y por herramientas de apoyo diagnóstico de inmunohistoquímica, las cuales detectaron antígenos virales en todos los órganos obtenidos en la necropsia. Este caso subraya la importancia del estudio de las infecciones primarias asociadas a dengue grave, particularmente en niños, en quienes es más probable el desarrollo de la forma grave de la enfermedad sin una infección previa, y, además, pone de relieve la importancia de un diagnóstico que no se limite a las muestras de tejido hepático en el estudio de la patogenia de la infección viral.

The epidemiological situation of dengue has worsened over the last decade. The difficulties in preventing its transmission and the absence of a vaccine or specific treatment have made dengue a serious risk to public health, health centers and research systems at different levels. Currently, most studies on the pathogenesis of dengue infection focus on the T-cell immune response almost exclusively in secondary infections and are aimed at identifying the mechanisms involved in the development of vascular permeability and bleeding events that accompany the infection. This report describes the case of a baby girl less than 45 days of age with clinical signs of severe dengue, whose diagnosis was confirmed by reverse transcription polymerase chain reaction in post-mortem tissue samples and by the ancillary diagnostic use of immunohistochemistry, which detected viral antigens in all organs obtained at autopsy. This case highlights the importance of studying primary infections associated with severe dengue, particularly in children, who are more likely to develop the severe form of the disease without previous infection, and it further stresses the importance of a diagnosis that should not be based solely on the examination of liver tissue samples when studying the pathogenesis of the viral infection.

Glucógeno hepático en dengue severo: análisis histopatológico / Hepatic glucogen in cases with severe dengue: histopathological changes

Antecedentes: El virus del dengue afecta distintos órganos, pero se ha determinado que el hígado es el principal blanco de acción y en donde ocurre la mayor severidad del daño. Existen pocos estudios sobre los cambios histológicos durante la infección por dengue. Objetivos: Analizar las alteraciones histopatológicas post-mortem en hígados de pacientes que presentaron la forma grave del dengue. Métodos: Se revisaron los cortes de hígado de 20 pacientes con dengue severo y se realizaron coloraciones y pruebas para glucógeno. Resultados: Encontramos pérdida de glucógeno citoplasmático en todos los casos analizados y la presencia de glucógeno intranuclear en dos de ellos. Conclusiones: En este estudio se reporta por primera vez la presencia de masas de glucógeno intranuclear en hepatocitos de dos niños fallecidos con dengue grave.

Background: Dengue virus affects various organs, but the liver is the main target of damage and where the most severe damage can occur. There are few studies on the histological changes in the liver during dengue infection. Aims: To analyze the histopathological post-mortem alterations in livers from patients with Methods: We revised serial liver sections, which were stained and tested for glycogen, from 20 patients with severe dengue. Results: We found loss of cytoplasmic glycogen in all cases analyzed and the presence of intranuclear glycogen in two of them. Conclusions: This is the first report of the presence of intranuclear glycogen masses during severe dengue.

Alteraciones morfológicas en pulmón por la influenza A H1N1/v09 en autopsias, Colombia, 2009 / Morphological changes in lung tissue of victims associated with the 2009 A H1N1/v09 influenza pandemic in Colombia

Introducción. La influenza es una infección respiratoria aguda que se presenta de forma estacional y pandémica. En el 2009, la Organización Mundial de Salud (OMS) declaró una pandemia por influenza de tipo A en la que se reportaron en Colombia 3.876 casos de infección, de los cuales 239 fallecieron. Objetivo. Describir los cambios morfológicos asociados a la infección por el virus A H1N1/v09 en tejido pulmonar de autopsias de la pandemia de 2009 en Colombia.Materiales y métodos. Se estudiaron 75 casos con diagnóstico por RT-PCR para el virus A H1N1/v09, de los cuales, 20 fueron seleccionados para el estudio morfológico mediante microscopía convencional de luz, microscopía óptica de alta resolución y electrónica de transmisión e inmunohistoquímica.Resultados. De los 75 casos estudiados, 83 % presentaron pneumonitis viral y 17 % alveolitis. Se observaron complicaciones por hemorragia intraalveolar (66 %) y edema (89 %), daño alveolar difuso (2 %) e infección bacteriana concomitante (32 %).Algunos de los cambios morfológicos observados fueron: destrucción del epitelio alveolary el instersticio, edema, macrófagos con citoplasma vacuolado e infiltración de leucocitos polimorfonucleares en la luz alveolar y el intersticio; vacuolización citoplásmica en neumocitos de tipo I y cuerpos electrodensos en restos celulares en la luz alveolar; inmunorreacción de antígenos virales en el epitelio bronquiolar y en células del infiltrado alveolar. Conclusión. El porcentaje bajo de infección bacteriana concomitante observado en los casos de influenza A H1N1/ v09 en este estudio, es una característica sobresaliente que sugiere que el resultado fatal de la infección, probablemente no esté asociado a una enfermedad bacteriana secundaria, como se ha sugerido en reportes previos. Es probable que las lesiones observadas se puedan atribuir al daño tisular en la respuesta inflamatoria celular y humoral asociada a la infiltración por células poliformonucleares y macrófagos en el intersticio y la luz alveolares, como también por la lesión viral.

Introduction. Influenza is an acute respiratory infection that may be seasonal or pandemic. In 2009 The World Health Organization (WHO) declared an influenza pandemia; 3,876 cases and 239 deaths were reported in Colombia. Objective. The morphological changes in lung tissues associated with virus infection H1N1/v09 were described from autopsied victims.Materials and methods. Seventy-five cases were diagnosed by RT-PCR for influenza A H1N1/v09, of which the lungs of 20 were selected for morphological study by light microscopy, optical microscopy, high-resolution transmission electron microscopy and immunohistochemistry. Results. Of the 75 cases, 83% had viral pneumonitis and 17% alveolitis. Complications included intra-alveolar hemorrhage (66%), edema (89%), diffuse alveolar damage (2%), and bacterial co-infection (32%). Morphological changes were as follows: destruction of the alveolar epithelium and interstitium, edema, macrophages with vacuolated cytoplasm,and infiltration of polymorphonuclear leukocytes in the alveolar lumen and interstitium, vacuolization cytoplasmic type I pneumocytes and electron-dense bodies in cellular debris in the alveolar lumen, and immunoreactivity of viral antigens in bronchiolar epithelial cells and alveolar infiltrate. Conclusion. The low percentage of bacterial co-infection observed in these cases was a prominent feature, and suggested that the fatal result was probably not associated with secondary bacterial disease (Indicated by previous reports). The tissue lesions were attributed to tissue damage due to viral lesion, as well as the cellular and humoral inflammatory response associated with infiltration by polymorphonucleocytes and macrophages in the interstitium and alveolar lumen.

[Morphological changes in lung tissue of victims associated with the 2009 A H1N1/v09 influenza pandemic in Colombia]. / Alteraciones morfológicas en pulmón por la influenza A H1N1/v09 en autopsias, Colombia, 2009.

INTRODUCTION: Influenza is an acute respiratory infection that may be seasonal or pandemic. In 2009 The World Health Organization (WHO) declared an influenza pandemia; 3,876 cases and 239 deaths were reported in Colombia. OBJECTIVE: The morphological changes in lung tissues associated with virus infection H1N1/v09 were described from autopsied victims. Materials and methods. Seventy-five cases were diagnosed by RT-PCR for influenza A H1N1/v09, of which the lungs of 20 were selected for morphological study by light microscopy, optical microscopy, high-resolution transmission electron microscopy and immunohistochemistry. RESULTS: Of the 75 cases, 83% had viral pneumonitis and 17% alveolitis. Complications included intra-alveolar hemorrhage (66%), edema (89%), diffuse alveolar damage (2%), and bacterial co-infection (32%). Morphological changes were as follows: destruction of the alveolar epithelium and interstitium, edema, macrophages with vacuolated cytoplasm,and infiltration of polymorphonuclear leukocytes in the alveolar lumen and interstitium, vacuolization cytoplasmic type I pneumocytes and electronedense bodies in cellular debris in the alveolar lumen, and immunoreactivity of viral antigens in bronchiolar epithelial cells and alveolar infiltrate. CONCLUSION: The low percentage of bacterial co-infection observed in these cases was a prominent feature, and suggested that the fatal result was probably not associated with secondary bacterial disease (Indicated by previous reports). The tissue lesions were attributed to tissue damage due to viral lesion, as well as the cellular and humoral inflammatory response associated with infiltration by polymorphonucleocytes and macrophages in the interstitium and alveolar lumen.

Detección por reacción en cadena de la polimerasa de transcriptasa inversa del virus de la fiebre amarilla en monos silvestres: una herramienta sensible para la vigilancia epidemiológica / Detection of yellow fever virus by reverse transcriptase polymerase chain reaction in wild monkeys: a sensitive tool for epidemiologic surveillance

Introducción. La fiebre amarilla es una enfermedad zoonótica mantenida en la naturaleza por primates no humanos; su vigilancia por técnicas sensibles de laboratorio es necesaria para hacer evidente la actividad viral en territorio selvático. Objetivo. Detectar el virus de la fiebre amarilla en muestras de tejido hepático de primates no humanos, mediante la técnica de reacción en cadena de la polimerasa de transcriptasa inversa (RT-PCR) con iniciadores diagnósticos específicos. Materiales y métodos. Se procesaron muestras de tejido hepático de cinco monos del genero Alouatta spp. encontrados muertos en territorio selvático de los departamentos de Cesar y Magdalena entre diciembre de 2003 y junio de 2004. Las muestras fueron tratadas con una solución de lisis para aislar el ARN viral que, posteriormente, fue utilizado en una RT-PCR, utilizando iniciadores específicos para fiebre amarilla; paralelamente, se identificaron proteínas virales mediante inmunohistoquímica sobre cortes de tejido hepático incluidos en parafina. Resultados. Se obtuvieron productos de amplificación del tamaño esperado, (424 pb) en cuatro de las muestras analizadas; estas muestras mostraron, además, una reacción inmunohistoquímica positiva, lo que confirma la presencia del virus. Conclusión. El hallazgo del virus de la fiebre amarilla en monos silvestres representa una evidencia de su actividad enzoótica en nuestro territorio, que incrementa el riesgo de transmisión a humanos y de urbanización por procesos de migración de la población. La detección por técnicas moleculares rápidas y específicas del virus en monos silvestres representa una herramienta de vigilancia epidemiológica que permite activar de manera precoz los sistemas de control necesarios para impedir brotes y epidemias.

Introduction. Yellow fever is a zoonotic infection maintained in nature by non-human primates. Appropriate surveillance with sensitive laboratory techniques is necessary to evidence viral activity in the tropical forest habitats of these primates. Objective. Yellow fever virus was detected in hepatic tissue samples from non-human primates by reverse transcriptase polymerase chain reaction (RT-PCR) technique using specific primers for diagnosis. Materials and methods. Hepatic tissue samples were processed from five monkeys belonging genus Alouatta spp found dead in sylvatic areas of Cesar and Magdalena Provinces, Colombia, between December 2003 and June 2004. Samples were treated with lysis buffer prior to the isolation of viral RNA, which was then subjected to reverse transcriptase polymerase chain reaction (RT-PCR) using yellow fever-specific primers. Simultaneously, viral proteins were identified by immunohistochemistry on parafin-embedded hepatic tissue. Results. The PCR method amplified fragments of the expected size (424 bp) in four of the tested samples. In addition, these samples showed a positive reaction by immunohistochemistry, supporting the evidence that the virus was present. Conclusion. The detection of yellow fever virus in wild monkeys was clear evidence of enzootic activity in northern Colombia. Increased probability of yellow fever transmission among human populations is indicated due to urbanization processes as a consequence of forced migration and displacement of the human populations. Molecular tests for rapid and specific detection of yellow fever in tissue samples of non-human primates is an important tool for epidemiologic surveillance. Rapid virus identification will permit the timely activation of control systems for prevention of further cases and epidemic situations.

[Detection of yellow fever virus by reverse transcriptase polymerase chain reaction in wild monkeys: a sensitive tool for epidemiologic surveillance]. / Detección por reacción en cadena de la polimerasa de transcriptasa inversa del virus de la fiebre amarilla en monos silvestres: una herramienta sensible para la vigilancia epidemiológica.

INTRODUCTION: Yellow fever is a zoonotic infection maintained in nature by non-human primates. Appropriate surveillance with sensitive laboratory techniques is necessary to evidence viral activity in the tropical forest habitats of these primates. OBJECTIVE: Yellow fever virus was detected in hepatic tissue samples from non-human primates by reverse transcriptase polymerase chain reaction (RT-PCR) technique using specific primers for diagnosis. MATERIALS AND METHODS: Hepatic tissue samples were processed from five monkeys belonging genus Alouatta spp found dead in sylvatic areas of Cesar and Magdalena Provinces, Colombia, between December 2003 and June 2004. Samples were treated with lysis buffer prior to the isolation of viral RNA, which was then subjected to reverse transcriptase polymerase chain reaction (RT-PCR) using yellow fever-specific primers. Simultaneously, viral proteins were identified by immunohistochemistry on parafin-embedded hepatic tissue. RESULTS: The PCR method amplified fragments of the expected size (424 bp) in four of the tested samples. In addition, these samples showed a positive reaction by immunohistochemistry, supporting the evidence that the virus was present. CONCLUSION: The detection of yellow fever virus in wild monkeys was clear evidence of enzootic activity in northern Colombia. Increased probability of yellow fever transmission among human populations is indicated due to urbanization processes as a consequence of forced migration and displacement of the human populations. Molecular tests for rapid and specific detection of yellow fever in tissue samples of non-human primates is an important tool for epidemiologic surveillance. Rapid virus identification will permit the timely activation of control systems for prevention of further cases and epidemic situations.

[Image analysis to quantify S100-positive dendritic cells in leprosy-affected skin]. / Utilización de análisis de imágenes para cuantificar células dendríticas S100 positivas en piel con lepra.

A morphometric analysis of skin dendritic cells was done on biopsies of patients with different forms of leprosy. An anti S100 antibody was used to determine dendritic cell quantity and extension. Patients with a better immune response to the bacillus showed a greater number of dendritic cells in the cases of dimorphic tuberculoid leprosy and tuberculoid leprosy. This result contrasted with that from patients with dimorphic lepromatous leprosy and lepromatous leprosy.

Utilización de análisis de imágenes para cuantificar células dendríticas S100 positivas en piel con lepra / Image analysis to cuantify S100 - positive dendritic cells in leprosy - affected skin

Se realizó un análisis morfométrico de células dendríticas de piel, que incluyó la determinación de la cantidad y el área ocupada, empleando un anticuerpo anti-S100 en biopsias de pacientes con diferentes tipos de lepra. El análisis reveló las diferencias entre los pacientes que presentaban una mejor respuesta inmune al bacilo, reflejada en una mayor cantidad de células dendriticas en los casos de lepra dimorfa tuberculoide y lepra tuberculoide con respecto a aquellos pacientes con lepra dimorfa lepromatosa y lepra lepromatosa.