Niños hospitalizados con influenza en un hospital pediátrico de Argentina durante 2019-2022: ¿qué ha cambiado luego de la pandemia por COVID-19? / Children with influenza admitted at a children's hospital in Argentina in the 2019­2022 period: What has changed after the COVID-19 pandemic?

Introducción. Durante 2020 y 2021, la circulación de los virus influenza se mantuvo por debajo de lo esperado en todo el mundo. En Argentina, en el año 2022 observamos una circulación ininterrumpida de influenza todo el año. Nuestros objetivos fueron describir los patrones de circulación y las características clínicas de niños internados con influenza. Población y métodos. Estudio retrospectivo, analítico, observacional. Se incluyeron todos los niños internados en un centro pediátrico con detección del virus influenza durante los años 2019-2022. Resultados. Se internaron 138 pacientes en 4 años; en 2019 se observó una tasa del 4,5/1000 egresos hospitalarios mientras que en 2022, fue del 15,1/1000. En 2020 y 2021 no hubo casos. En el 2019 la mayoría de los casos ocurrieron en invierno, la causa de la internación fue la infección respiratoria aguda baja (IRAB) en el 79 % y se detectó influenza A en el 92 % de los casos. En el 2022, la mayoría de los casos ocurrieron en primavera, el 62 % presentó IRAB y en el 56 % se detectó influenza A. Ambos períodos tuvieron similares frecuencias de vacunación y de comorbilidades. Conclusiones. En el 2022 se registraron más internaciones por influenza, lo que podría corresponder a que se realizaron métodos diagnósticos moleculares, que son más sensibles, y se observó un cambio en la estacionalidad con más casos en primavera. En 2019 predominó influenza A en infecciones del tracto respiratorio inferior, mientras que en el 2022 influenza A y B fueron similares, y hubo más formas extrapulmonares.

Introduction. During 2020 and 2021, the circulation of influenza virus remained below expectations worldwide. In Argentina, in 2022, we observed an uninterrupted circulation of influenza all year round. Our objectives were to describe the circulation patterns and clinical characteristics of hospitalized children with influenza. Population and methods. Retrospective, analytical, observational study. All children with influenza virus admitted to a children's hospital during the 2019­2022 period were included. Results. A total of 138 patients were admitted over 4 years; in 2019, the rate of hospital discharges was 4.5/1000, compared to 15.1/1000 in 2022. No cases were recorded in 2020 and 2021. In 2019, most cases were observed in the winter; in 79%, the cause was acute lower respiratory tract infection (ALRTI); influenza A was detected in 92%. In 2022, most cases occurred in the spring; 62% developed ALRTI; and influenza A was detected in 56%. Similar rates of vaccination and comorbidities were observed in both periods. Conclusions. In 2022, more hospitalizations due to influenza were recorded, which may have correlated with the use of more sensitive molecular diagnostic testing and a change in seasonality, with more cases observed in the spring. In 2019, influenza A predominated in lower respiratory tract infections, while in 2022, cases of influenza A and B were similar, with more extra-pulmonary forms.

Use of oral fluids for efficient monitoring of influenza viruses in swine herds in Colombia

Background: Influenza A virus (IAV) surveillance in swine is critical not only due to the direct impact of the disease in the pork industry but also because IAV are prone to interspecies transmission (from human to pigs and vice versa); therefore, its monitoring is fundamental from a public and animal health perspective. Several diagnostic techniques have been used to detect IAV infection from nasal samples in swine, while samples of oral fluids (OF) are in use as novel alternatives for pathogen detection. The OF allow for efficient and feasible low-cost disease detection at the herd level, with low risk of stress for the animals. Objective: To describe a surveillance strategy of IAV at the herd level during respiratory disease outbreaks in swine farms at tropical settings using porcine oral fluids. Methods: An active surveillance strategy was conducted in several farms with past records of respiratory disease. The IAV detection was conducted in five purposively selected swine farms from years 2014 to 2017. We investigated a total of 18 respiratory outbreaks of the disease. Swine OF were collected for IAV testing. An OF sample is described as a pen-based specimen collected from a group of >20 pigs per pen and/or per barn (stall-housed individually with close contact among them). The IAV infection was investigated in OF by rRT-PCR testing and confirmed by viral isolation in cell culture Results: We found 107 (7.4%) positives to IAV by rRT-PCR from a total of 1,444 OF samples tested. Additionally, 9 IAV isolates were all further identified as H1 subtype. Conclusions: Our results demonstrate that OF can be easily implemented as a novel, user-friendly, welfare-friendly, accurate and cost-effective sampling method for active surveillance and monitoring of IAV infections in swine farms in tropical settings.

Antecedentes: La vigilancia del Virus Influenza A (IAV) en los cerdos es fundamental debido al impacto directo de la enfermedad en la industria porcina, pero también porque los IAV son propensos de transmisión entre especies (humanos a cerdos y viceversa), y por lo tanto su monitoreo es crítico desde las perspectivas de salud pública y animal. Actualmente existen varias técnicas de diagnóstico disponibles para detectar la infección por IAV a partir de muestras nasales en cerdos, sin embargo, se han implementado otras muestras como los fluidos orales (OF) como nuevas alternativas para la detección de patógenos. El OF permite una detección eficiente y factible de enfermedades a menor costo a nivel de rebaño, con menor riesgo de estrés para los animales. Objetivo: Describir una estrategia de vigilancia de IAV a nivel de hato por medio de fluidos orales porcinos durante brotes de enfermedades respiratorias en granjas porcinas en entornos tropicales. Métodos: Se llevó a cabo una estrategia de vigilancia activa en cinco granjas porcinas seleccionadas con antecedentes de enfermedades respiratorias. Se recolectaron OF porcinos para la prueba de IAV. Una muestra de OF se describió como una muestra grupal recolectada de un grupo de >20 cerdos por corral y/o por establo (si estaban alojados individualmente, pero tenían un contacto cercano entre ellos). La infección por IAV se investigó probando OF mediante rRT-PCR y la confirmación mediante aislamiento viral en cultivo celular. Resultados: La detección de IAV se llevó a cabo en cinco granjas seleccionadas intencionalmente entre 2014- 2017. Investigamos un total de 18 eventos de brotes de enfermedades respiratorias. Del total de 1.444 OF muestras analizadas, encontramos 107 (7,4%) positivos a IAV mediante rRT-PCR. Además, solo se obtuvieron 9 aislamientos de IAV y todos se identificaron además como subtipo H1. Conclusiones: Los resultados de nuestro estudio demostraron cómo la OF puede implementarse fácilmente como un método de muestreo novedoso, fácil de usar, amigable con el bienestar animal, preciso y rentable para la vigilancia activa y el monitoreo de infecciones por IAV en granjas porcinas en entornos tropicales.

Antecedentes: A vigilância do vírus Influenza A (IAV) em suínos é crítica devido ao impacto direto da doença na indústria de suínos, mas também porque os IAV são propensos a transmissão interespécies (de humanos para porcos e vice-versa) e, portanto, seu monitoramento é crítico do ponto de vista da saúde pública e animal. Atualmente, existem várias técnicas de diagnóstico disponíveis para detectar a infecção por IAV em amostras nasais de suínos, no entanto, outras amostras, como fluidos orais (OF), têm sido implementadas como novas alternativas para a detecção de patógenos. O OF permite uma detecção eficiente e viável de doenças com menor custo em nível de rebanho, com menor risco de estresse para os animais. Objetivo: Descrever uma estratégia de vigilância de IAV em nível de rebanho durante surtos de doenças respiratórias em granjas de suínos em ambientes tropicais por meio de fluidos orais suínos. Métodos: A estratégia de vigilância ativa foi conduzida em cinco granjas de suínos selecionadas com histórico de doenças respiratórias. Suínos OF foram coletados para teste de IAV. Uma amostra OF foi descrita como um espécime baseado em curral coletado de um grupo de >20 porcos por curral e/ou por celeiro (se eles foram alojados individualmente, mas tendo contato próximo entre eles). A infecção IAV foi investigada testando OF por rRT-PCR e confirmada por isolamento em cultura de células. Resultados: A detecção do IAV foi realizada em cinco fazendas selecionadas propositalmente entre 2014-2017. Nós investigamos um total de 18 eventos de surto de doença respiratória. Do total de 1.444 amostras de OF testadas, encontramos 107 (7,4%) positivas para IAV por rRT-PCR. Além disso, apenas 9 isolados de IAV foram obtidos, e todos foram posteriormente identificados como subtipo H1. Conclusão: Os resultados de nosso estudo demonstraram como o OF pode ser facilmente implementado como um método de amostragem novo, amigável, amigável com o bem-estar, preciso e de baixo custo para vigilância ativa e monitoramento de infecções IAV em fazendas de suínos em ambientes tropicais.

Understanding the outcomes of COVID-19 - does the current model of an acute respiratory infection really fit?

Although coronavirus disease 2019 (COVID-19) is regarded as an acute, resolving infection followed by the development of protective immunity, recent systematic literature review documents evidence for often highly prolonged shedding of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in respiratory and faecal samples, periodic recurrence of PCR positivity in a substantial proportion of individuals and increasingly documented instances of reinfection associated with a lack of protective immunity. This pattern of infection is quite distinct from the acute/resolving nature of other human pathogenic respiratory viruses, such as influenza A virus and respiratory syncytial virus. Prolonged shedding of SARS-CoV-2 furthermore occurs irrespective of disease severity or development of virus-neutralizing antibodies. SARS-CoV-2 possesses an intensely structured RNA genome, an attribute shared with other human and veterinary coronaviruses and with other mammalian RNA viruses such as hepatitis C virus. These are capable of long-term persistence, possibly through poorly understood RNA structure-mediated effects on innate and adaptive host immune responses. The assumption that resolution of COVID-19 and the appearance of anti-SARS-CoV-2 IgG antibodies represents virus clearance and protection from reinfection, implicit for example in the susceptible-infected-recovered (SIR) model used for epidemic prediction, should be rigorously re-evaluated.

Infecção pelo vírus influenza A em suínos no sul de Moçambique / Influenza A virus infection in pigs in southern Mozambique

A influenza suína (IS) é uma doença aguda e altamente contagiosa do trato respiratório de suínos, causada pelo vírus influenza A (VIA). A doença provoca perdas econômicas na suinocultura e também, tem importância na saúde pública devido ao seu potencial zoonótico. O objetivo deste trabalho foi relatar a infecção pelo VIA em suínos de Moçambique e realizar a caracterização anatomopatológica e imuno-histoquímica (IHQ) das lesões pulmonares associadas. Pulmões de 457 suínos abatidos foram avaliados e coletados 38 (8,3%) pulmões de suínos com áreas de consolidação pulmonar em um abatedouro na cidade da Matola, no Sul de Moçambique. As áreas de consolidação em cada lobo pulmonar foram classificadas em 4 graus de acordo com a extensão da lesão. Amostras de pulmões com consolidação foram submetidas ao exame histopatológico e IHQ para a detecção de antígenos do VIA, Circovírus suíno tipo 2 (PCV2) e Mycoplasma hyopneumoniae. Os pulmões coletados apresentaram áreas multifocais ou coalescentes de consolidação pulmonar, frequentemente, observadas nos lobos craniais, mediais e acessório. Estas lesões acometiam principalmente um ou três lobos pulmonares e as lesões de grau 1 e 2 foram as mais frequentes. As principais lesões histopatológicas observadas foram bronquiolite necrotizante (23/38), infiltrado de neutrófilos nos alvéolos (24/38), hiperplasia de pneumócitos tipo II (26/38), hiperplasia de tecido linfoide peribronquiolar (28/38), e pneumonia intersticial mononuclear (29/38). No exame de IHQ, antígenos do VIA foram detectados em 84.3% (32/38) dos pulmões com pneumonia, e a nucleoproteína do vírus foi visualizada, no núcleo de células epiteliais de brônquios e bronquíolos e em macrófagos alveolares. Suínos positivos para o VIA na IHQ eram provenientes do distrito de Matutuine (5/32), distrito da Moamba (2/32), distrito de Namaacha (21/32), distrito de Boane (3/32) e Cidade da Matola (1/32). Todas as amostras foram negativas para PCV2 e Mycoplasma hyopneumoniae pelo exame de IHQ. Os resultados demonstram que o VIA está presente e é causa de pneumonia em suínos em Moçambique.(AU)

Swine influenza (SI) is an acute and highly contagious disease of the respiratory tract of pigs caused by influenza A virus (IAV). The disease causes economic losses in swine production and is of great public importance for its zoonotic potential. The aim of the present study was to report IAV infection in pigs from Mozambique and characterize the anatomopathological and immunohistochemical features of associated lung lesions. Lungs from 457 slaughtered pigs were subjected to gross evaluation and 38 (8.3%) lungs with cranioventral consolidation were collected from a slaughterhouse in Matola City, southern Mozambique. Areas of consolidation in each lung lobe were classified in 4 grades according to the lesion extension. Samples with consolidated lung tissue were examined for histopathology and immunohistochemistry (IHC) for the presence of IAV, Porcine circovirus type 2 (PCV2) and Mycoplasma hyopneumoniae antigens. The lungs had multifocal to coalescing areas of consolidation observed most frequently in the cranial, middle, and accessory lobes. The lesions involved mainly one or three pulmonary lobes and grade 1 and 2 lesions were the most frequent. The main histopathological findings were necrotizing bronchiolitis (23/38), alveolar neutrophil infiltration (24/38), type II pneumocytes hyperplasia (26/38), peribronchiolar lymphoid tissue hyperplasia (28/38) and interstitial mononuclear cells infiltrate (29/38). Immunohistochemistry revealed positive staining in 84.3% (32/38) of the samples and IAV nucleoprotein was present in the nucleus of bronchial and bronchiolar epithelial cells and alveolar macrophages. Positive IHC pigs were from Matutuine district (5/32), Moamba district (2/32), Namaacha district (21/32), Boane district (3/32) and Matola city (1/32). All lung samples were immunohistochemically negative for PCV2 and Mycoplasma hyopneumoniae. These results demonstrate that IAV is a cause of pneumonia in pigs in Mozambique.(AU)

Patients with influenza A (H1N1)pdm09 admitted to the ICU. Impact of the recommendations of the SEMICYUC. / Pacientes con gripe por el virus influenza A (H1N1)pdm09 ingresados en la UCI. Impacto de las recomendaciones de la SEMICYUC.

OBJECTIVES: To evaluate the impact of the recommendations of the SEMICYUC (2012) on severe influenza A. DESIGN: A prospective multicenter observational study was carried out. SETTING: ICU. PATIENTS: Patients infected with severe influenza A (H1N1) from the GETGAG/SEMICYUC registry. INTERVENTIONS: Analysis of 2 groups according to the epidemic period of the diagnosis (2009-2011; 2013-2015). VARIABLES: Demographic, temporal, comorbidities, severity, treatments, mortality, late diagnosis and place of acquisition. RESULTS: A total of 2,205 patients were included, 1,337 (60.6%) in the first period and 868 (39.4%) in the second one. Age and severity on admission were significantly greater in the second period, as well as co-infection. With regard to the impact of the recommendations, in the second period the diagnosis was established earlier (70.8 vs. 61.1%, P<.001), without changes in the start of treatment. Patients received less corticosteroid treatment (39.7 vs. 44.9%, P<.05), more NIMV was used (47.4 vs. 33.2%, P<.001) and more vaccination was made (11.1 vs. 1.7%, P<.001), without changes in mortality (24.2 vs. 20.7%). A decrease in nosocomial infection was also noted (9.8 vs. 16%, P<.001). Patients needed less MV with more days of ventilation, more vasopressor drug use and more ventral decubitus. CONCLUSIONS: The management of patients with severe influenza A (H1N1) has changed over the years, though without changes in mortality. The recommendations of the SEMICYUC (2012) have allowed earlier diagnosis and improved corticosteroid use. Pending challenges are the delay in treatment, the vaccination rate and the use of NIMV.

Functional role of Hsp60 as a positive regulator of human viral infection progression.

Heat shock proteins (Hsps) are a family of proteins highly conserved in evolution. Members of the Hsp family are mainly responsible for proper protein folding, however they perform many other functions in living organisms. Hsp60 is a molecular chaperone that is present in mitochondria and cytosol of eukaryotic cells, as well as on their surface. It is also found in the extracellular space and in the peripheral blood. Apart from its role in assisting protein folding in cooperation with Hsp10, Hsp60 contributes to regulation of apoptosis, as well as participates in modulation of the immune system activity. Hsp60 may favor oncogenesis by promoting survival or growth of some tumor cell types. Hsp60 is a subject of medical research due to its role in pathogenesis of certain tumors and infectious diseases. In this review we discuss mechanisms by which Hsp60 promotes development and progression of infections caused by three human viruses: hepatitis B virus (HBV), human immunodeficiency virus (HIV) and influenza A virus.

Encefalitis hemorrágica por influenza A H1N1: presentación de un caso y revisión de la literatura / H1N1 influenza hemorrhage encephalitis: presentation of a case and review of the literature

RESUMEN Las complicaciones neurológicas asociadas a los virus respiratorios (en especial la influenza) son descritas de manera poco frecuente. Particularmente el virus influenza A subtipo H1N1 tiene escasos reportes, la mayoría proviene de niños y adultos jóvenes. Presentamos el caso del adulto mayor con un cuadro infeccioso respiratorio y múltiples complicaciones sistémicas graves a su cuadro primario, quien durante la estancia hospitalaria presentó un cuadro encefalopático, con características clínicas y radiológicas muy sugestivas de encefalitis hemorrágica debido a su agente primario infeccioso, en este caso influenza A H1N1.

SUMMARY Neurological complications associated with respiratory viruses such as influenza, are described infrequently. Particularly influenza A(H1N1) has few descriptions most of which come from children and young adults. We present the case of the elderly with respiratory infectious picture and multiple serious systemic complications to your primary table, who during the hospital stay has a encephalopathic box with suggestive clinical and radiologic features of hemorrhagic encephalitis due to its infectious primary agent in this case influenza A H1N1.

Perfil epidemiológico dos casos de Influenza A em Santa Catarina, Brasil no ano de 2012 / Epidemiological profile of notified cases of Influenza A in the state of Santa Catarina, Brazil in 2012

O objetivo deste estudo foi descrever o perfil epidemiológico dos casos notificados de Influenza A no Estado de Santa Catarina, Brasil, no ano de 2012. Trata-se de um estudo ecológico envolvendo dados de indivíduos notificados como casos suspeitos de infecção pelo H1N1 em 2012. Dados de notificação compulsória do Sistema de Informação de Agravos de Notificação e do Sistema de Informações sobre Mortalidade foram coletados por técnicos da Diretoria de Vigilância Epidemiológica de Santa Catarina. Para o diagnóstico de infecção pelo H1N1, foi considerada Reação de Cadeia da Polimerase em Tempo Real - RT-PCR positivo como exame laboratorial ou quadro de síndrome respiratória aguda grave. Foram notificados 3.282 casos, nos quais 239 (24,5%) confirmados pelo RT-PCR para H1N1 sazonal. Obteve-se taxa de morbidade de 3,68/100 mil habitantes e taxa de mortalidade de 0,14/100 mil habitantes. A idade média das notificações foi 31 anos. A Região Sul do estado apresentou maior taxa de confirmações. Observou-se maior proporção de casos confirmados em indivíduos com idade ≥60 anos (p<0,001). Não se observou diferença em relação ao sexo, cor de pele, escolaridade e gestação. Os indivíduos não apresentavam vacinação prévia contra o vírus Influenza em 67,5% dos casos. Foi possível observar divergências em relação aos dados nacionais como a faixa etária, no entanto, dados como sinais e sintomas e comorbidades mantiveram-se semelhantes.

The objective of this study was to describe the epidemiological profile of notified cases of influenza A in the State of Santa Catarina, Brazil in 2012. This is an ecological study involving data of individuals reported as suspected cases of H1N1 infection in 2012. Epidemiological surveillance officers collected data from the Brazilian communicable diseases information system. The diagnoses of H1N1 cases were confirmed by positive Real Time Polymerase Chain Reaction - RT-PCR or signs and symptoms characteristic of severe acute respiratory syndrome. 3,282 cases were reported and 239 (24.5%) by seasonal H1N1. The obtained morbidity rate was 3.68/100,000 inhabitants and the mortality rate was 0.14/100,000 inhabitants. The South region had a higher rate of confirmed cases with 13.1%. The average age of notifications was 31 years. Individuals aged ≥60 years presented a higher proportion of confirmed cases (p<0.001). There was no difference in relation to gender, skin color, educational level and pregnancy. 67,5% had no previous vaccination against the virus Influenza (p=0.078). It was observed divergence of national data concerning age, however, signs and symptoms and comorbidities remained similar.

High prevalence of common respiratory viruses and no evidence of Middle East respiratory syndrome coronavirus in Hajj pilgrims returning to Ghana, 2013.

OBJECTIVE: The Middle East respiratory syndrome coronavirus (MERS-CoV) emerged in 2012 on the Arabian Peninsula and has caused severe respiratory disease with more than 800 laboratory-confirmed cases. The return of infected pilgrims to their home countries with a putative spread of MERS-CoV necessitates further surveillance. METHODS: A cross sectional study of 839 adult African Hajj pilgrims returning to Accra in Ghana, West Africa, was conducted in 2013 to assess the prevalence of respiratory symptoms as well as of MERS-CoV, human rhinovirus (HRV), respiratory syncytial virus (RSV) and influenza A virus (FLU A) infection. RESULTS: Six hundred and fifty-one (77.6%) pilgrims had respiratory symptoms. Tests were positive for at least one of the viruses other than MERS-CoV in 179 (21.3%) of all pilgrims, with 22.4% detection in symptomatic vs. 17.6% detection in asymptomatic pilgrims. No MERS-CoV was detected, although common respiratory viruses were prevalent, with positive findings for HRV in 141 individuals (16.8%), RSV in 43 individuals (5.1%) and FLU A in 11 individuals (1.3%). Results were positive for more than one virus in 16 (1.9%) individuals, including 14 (1.7%) RSV/HRV co-infections and 2 (0.2%) FLU A/HRV co-infections. A total 146 (22.4%) of the symptomatic returnees tested positive for at least one respiratory virus compared with 33 (17.6%) of the asymptomatic pilgrims who had at least one detectable virus in their sample. CONCLUSIONS: The prevalence of viral respiratory infections among Hajj pilgrims in both symptomatic and asymptomatic subjects was high. Although it is reassuring that MERS-CoV was not detected in the tested population, there is a need for active surveillance of Hajj pilgrims.

Influenza: evolución a cuatro años de la pandemia: Hospital Nacional Profesor Alejandro Posadas, Argentina / Influenza: A four-year evolution of the pandemic: Prof. Alejandro Posadas National Hospital, Argentina

En el Hospital Nacional Profesor Alejandro Posadas se estudiaron la incidencia de influenza, las características de casos y tipos y subtipos de virus circulantes de enero a agosto de 2013 inclusive, semanas epidemiológicas (SE) 1-35, y se compararon con los años 2009-2012. De fin de mayo a agosto inclusive de 2013 (SE 18 a 35) se observó un aumento del porcentaje de consulta por enfermedades respiratorias, enfermedad tipo influenza e internación por neumonía y se diagnosticaron 207 casos: 153 influenza A (FLU-A)(H1N1pdm09), 46 A(H3), ocho A(sin subtipificar). La mayor frecuencia fue en menores de 5 años, seguida por el grupo de 60 a 64.La chance de tener la enfermedad fue tres veces mayor en el grupo de 40-64 años versus 15-39 o > 64 años. La letalidad, que aumentó con la edad, fue de 7.2% y la chance de morir fue seis veces mayor en los > 64 años. El porcentaje de vacunación entre los casos fue11.6%. Ninguno de los fallecidos estaba vacunado. Luego de la pandemia de 2009 el porcentaje de consultas anuales disminuyó hasta 2012, con un aumento en el período invernal de 2013 de 52.0% con respecto a 2012. La circulación viral en 2013 fue más temprana que en los años anteriores. En 2009 y 2013 la mayor circulación fue FLU-A (H1N1pdm), en 2011 FLU-A(H3) y en 2010 y 2012 FLU-A(H3) y FLU-B.(AU)

As from January to August 2013, epidemiological weeks 1-35 (EW), Influenza incidence, case characteristics, types and subtypes of circulating influenza virus in the Nacional Profesor Alejandro Posadas Hospital were studied, and were compared to incidences during 2009-2012. From late May to the end of August 2013 (EW18-35), an increase was observed in the proportion of patients visits for respiratory disease, influenza-like illness and hospitalizations due to pneumonia; of 207 cases diagnosed with influenza A virus, 153 were infected by H1N1pdm09, 46 by H3, and eight without subtype. The highest proportion of cases was found in children under five years of age, followed by the group 60-64.The chances of having the illness were three times greater among the group 40-64 years old compared to 15-39 or those older than 64. Mortality, which increased with age, was 7.2%, and the odds of death were six times higher among those older than 64. Vaccination rate among the cases was 11.6%. None of the fatal cases had received the vaccine. After the 2009 pandemic, the proportions of annual patients´ visits decreased until 2012; in 2013, an increase of 52.0% during the winter period compared to 2012. The viral circulation started earlier in 2013 compared to previous years. FLU-A(H1N1pdm) was the predominant circulating virus in 2009 and 2013, FLU-A(H3) in 2011, FLU-A(H3) and FLU-B in both 2010 and 2012.(AU)

Influenza: evolución a cuatro años de la pandemia: Hospital Nacional Profesor Alejandro Posadas, Argentina / Influenza: A four-year evolution of the pandemic: Prof. Alejandro Posadas National Hospital, Argentina

En el Hospital Nacional Profesor Alejandro Posadas se estudiaron la incidencia de influenza, las características de casos y tipos y subtipos de virus circulantes de enero a agosto de 2013 inclusive, semanas epidemiológicas (SE) 1-35, y se compararon con los años 2009-2012. De fin de mayo a agosto inclusive de 2013 (SE 18 a 35) se observó un aumento del porcentaje de consulta por enfermedades respiratorias, enfermedad tipo influenza e internación por neumonía y se diagnosticaron 207 casos: 153 influenza A (FLU-A)(H1N1pdm09), 46 A(H3), ocho A(sin subtipificar). La mayor frecuencia fue en menores de 5 años, seguida por el grupo de 60 a 64.La chance de tener la enfermedad fue tres veces mayor en el grupo de 40-64 años versus 15-39 o > 64 años. La letalidad, que aumentó con la edad, fue de 7.2% y la chance de morir fue seis veces mayor en los > 64 años. El porcentaje de vacunación entre los casos fue11.6%. Ninguno de los fallecidos estaba vacunado. Luego de la pandemia de 2009 el porcentaje de consultas anuales disminuyó hasta 2012, con un aumento en el período invernal de 2013 de 52.0% con respecto a 2012. La circulación viral en 2013 fue más temprana que en los años anteriores. En 2009 y 2013 la mayor circulación fue FLU-A (H1N1pdm), en 2011 FLU-A(H3) y en 2010 y 2012 FLU-A(H3) y FLU-B.

As from January to August 2013, epidemiological weeks 1-35 (EW), Influenza incidence, case characteristics, types and subtypes of circulating influenza virus in the Nacional Profesor Alejandro Posadas Hospital were studied, and were compared to incidences during 2009-2012. From late May to the end of August 2013 (EW18-35), an increase was observed in the proportion of patients' visits for respiratory disease, influenza-like illness and hospitalizations due to pneumonia; of 207 cases diagnosed with influenza A virus, 153 were infected by H1N1pdm09, 46 by H3, and eight without subtype. The highest proportion of cases was found in children under five years of age, followed by the group 60-64.The chances of having the illness were three times greater among the group 40-64 years old compared to 15-39 or those older than 64. Mortality, which increased with age, was 7.2%, and the odds of death were six times higher among those older than 64. Vaccination rate among the cases was 11.6%. None of the fatal cases had received the vaccine. After the 2009 pandemic, the proportions of annual patients´ visits decreased until 2012; in 2013, an increase of 52.0% during the winter period compared to 2012. The viral circulation started earlier in 2013 compared to previous years. FLU-A(H1N1pdm) was the predominant circulating virus in 2009 and 2013, FLU-A(H3) in 2011, FLU-A(H3) and FLU-B in both 2010 and 2012.

Orientações para o diagnóstico de influenza em suínos / Guidelines for diagnosis of swine influenza

Este trabalho descreve a colheita adequada de amostras, as técnicas/procedimentos disponíveis para o diagnóstico de influenza A em suínos, assim como os resultados e suas respectivas interpretações, para auxiliar médicos veterinários de campo na identificação dessa doença. Em suínos vivos, as amostras adequadas são: secreção nasal, fluido oral e sangue (soro). Para suínos mortos, colher preferencialmente amostras de pulmão com consolidação cranioventral. Secreção nasal e fragmentos de pulmão refrigerado são utilizados para detectar partícula viral viável (isolamento viral - IV) ou ácido nucleico viral (RT-PCR convencional e RT-PCR em tempo real). As amostras não devem ser congeladas, pois o vírus é inativado a -20°C. A caracterização molecular dos isolados é feita pela análise filogenética obtida pelo sequenciamento de DNA. O soro é utilizado para a detecção de anticorpos (Acs) por meio do teste da inibição da hemaglutinação e ELISA. O fluido oral pode ser utilizado para detecção de anticorpo (ELISA) ou de vírus. Fragmentos de pulmão fixados em formol a 10% são examinados microscopicamente para identificar pneumonia broncointersticial e para detecção de antígeno viral pela imuno-histoquímica (IHQ). Para o sucesso do diagnóstico, as amostras devem ser colhidas de suínos que estão preferencialmente na fase aguda da doença, para aumentar as chances de detecção viral. As melhores opções para o diagnóstico de influenza A em suínos vivos são RT-PCR e isolamento viral de amostras de swab nasal ou fluido oral. Pulmão para análise por RT-PCR, isolamento viral ou IHQ é a amostra de escolha em suínos mortos. Testes sorológicos têm valor diagnóstico limitado e são utilizados apenas para determinar o estado imune do rebanho, não indicando doença clínica, pois os Acs são detectados 7-10 dias pós-infecção (fase subaguda). O diagnóstico de influenza é importante para avaliar o envolvimento desse agente no complexo de doença respiratória suína. Além disso, o isolamento do vírus influenza é essencial para o monitoramento dos principais subtipos circulantes em uma determinada região ou país, assim como para a detecção de novos rearranjos virais, já que influenza é considerada uma zoonose.

This article is intended to describe the adequate sample collection, the laboratory procedures/techniques, the expected results and their interpretation for diagnosis of influenza infection in swine, serving as a support for field veterinarians. In live pigs, the samples to be taken are nasal secretions, oral fluids and blood. For dead pigs, preference should be given to samples of cranioventral lung consolidation. Nasal discharge and chilled lung fragments are used for detection of virus (virus isolation - VI) or viral nucleic acids (conventional RT-PCR and real-time RT-PCR). Samples should not be frozen, because the virus is inactivated at -20°C. Molecular characterization of isolates is performed by phylogenetic analysis of gene sequences obtained by DNA sequencing. Serum is used for the detection of antibodies using hemagglutination inhibition (HI) test and ELISA. Oral fluid may be used for either antibody (ELISA) or viral detection. Fragments of lung fixed in 10% formaldehyde are used for histopathological analysis to identify bronchointerstitial pneumonia, and for immunohistochemistry (IHC) for antigens. For a successful diagnosis, sampling should be preferably performed in the acute phase of the disease to improve chances of virus detection. The best options to perform the diagnosis of influenza A in a swine herd are RT-PCR and VI from nasal swabs or oral fluid in live pigs and/or lung tissue for RT-PCR, VI or IHC in dead pigs. Serological tests are of very limited diagnostic value and are useful only to determine the immune status of the herd, not indicating clinical disease, because antibodies are detected after 7-10 days post infection (subacute phase). The diagnosis of influenza is important to evaluate the involvement of this agent in the complex of respiratory diseases in pigs. Furthermore, the isolation of influenza virus is essential for monitoring the main subtypes circulating in a given region or country, as well as for the detection of potential new viral reassortants, because influenza is considered a zoonosis.

Efeitos do análogo triazólico da Ribavirina, PAR038, sobre a replicação in vitro do vírus influenza / Effects of a ribavirin triazolic analogue, PAR038, in the in vitro replication of influenza virus

Os vírus influenza representam uma das principais causas das infecções respiratórias agudas, e são de grande impacto para saúde pública devido a ocorrência de epidemias sazonais e pandemias. A variabilidade genética deste vírus e seu amplo espectro de hospedeiros dificulta o controle das infecções através da vacinação, o que torna os antivirais importantes na prevenção e tratamento. Até o presente momento, existem duas classes de antivirais disponíveis para o tratamento da infecção pelo vírus influenza, os bloqueadores de canal M2 (amandadina e rimantadina), que não são mais utilizados clinicamente pois as cepas circulantes são resistentes e os inibidores de neuraminidase (NAIs – oseltamivir e zanamivir), classe em uso clínico embora já tenham sido descritas cepas resistentes ao oseltamivir. Existe também a ribavirina, um antiviral de amplo espectro que inibe DNA/RNA polimerases virais mas é altamente citotóxico. Devido ao número limitado de drogas anti-influenza, vem sendo realizados estudos sobre a eficácia da ribavirina e sua combinação com NAIs para tratamento das infecções causadas pelo influenza. A RNA polimerase do vírus influenza vem sendo cada vez mais explorada como alvo para novas drogas, e, desta forma, o objetivo deste trabalho foi investigar o efeito antiviral do PAR038, um análogo triazólico da ribavirina como potencial inibidor da polimerase. O composto PAR038 se mostrou menos citotóxico para células MDCK e 400 vezes mais potente que a ribavirina, com CC50 > 1000 miM e IC50 = 0,07 miM. Nosso composto foi capaz de inibir a RNA polimerase do vírus influenza com EC50 igual a 1,6 +/- 0.15 miM, além de inibir a replicação viral em células A549 (IC50 = 21,2 miM) e apresentar propriedades imunomodulatórias, já que diminuiu os níveis de IL-8 e MCP-1 no sobrenadante das células A549 infectadas com o vírus influenza...

Influenza virus represents one of the main causes of acute respiratory infections, beinga major cause of mortality, morbidity and burden to public health system. The geneticvariability of influenza viruses and broad spectrum of these viruses` hosts impose difficultiesin control strategies through vaccination. Therefore, antiviral drugs have become critical in theprevention and treatment of the infections caused by influenza viruses. There are two classesof anti-influenza drugs, M2 channel blockers (amantadine and rimantadine), which are nolonger used since circulating strains are resistant to these antivirals, and neuraminidaseinhibitors (NAIs – oseltamivir and zanamivir), in clinical use. Despite that, oseltamivirresistantstrains have been described. An additional antiviral, ribavirin, is endowed with abroad spectrum activity against DNA/RNA polymerases, although high cytotoxic has beendescribed. Due to the limited number of anti-influenza drugs, studies have been carried out onthe effectiveness of ribavirin and its combination with NAIs for treating influenza infections.Thus, influenza RNA polymerase still is a valid target for development of novel antiviral.Based on that, we aimed here to investigate the antiviral effect of PAR038, a triazolicanalogue of ribavirin. PAR038 is 400-fold potent than ribavirin, with CC50 > 1000 µM andIC50 = 0,07 µM towards MDCKs cytotoxicity and influenza in vitro replication. Ourcompound inhibits influenza RNA polymerase with an EC50 of 1,6 ± 0,15 µM and alsoinhibits viral replication in an A549 cells (IC50 = 21,2 µM)...

Histopathological and immunohistochemical findings of swine with spontaneous influenza A infection in Brazil, 2009-2010 / Achados histopatológicos e imuno-histoquímicos de suínos com infecção espontânea de influenza A no Brasil, 2009-2010

Swine influenza (SI) is caused by the type A swine influenza virus (SIV). It is a highly contagious disease with a rapid course and recovery. The major clinical signs and symptoms are cough, fever, anorexia and poor performance. The disease has been associated with other co-infections in many countries, but not in Brazil, where, however, the first outbreak has been reported in 2011. The main aim of this study was to characterize the histological features in association with the immunohistochemical (IHC) results for influenza A (IA), porcine circovirus type 2 (PCV2) and porcine reproductive and respiratory syndrome virus (PRRSV) in lung samples from 60 pigs submitted to Setor de Patologia Veterinária at the Universidade Federal do Rio Grande do Sul (SPV-UFRGS), Brazil, during 2009-2010. All of these lung samples had changes characterized by interstitial pneumonia with necrotizing bronchiolitis, never observed previously in the evaluation of swine lungs in our laboratory routine. Pigs in this study had showed clinical signs of a respiratory infection. Swine samples originated from Rio Grande do Sul 31 (52%), Santa Catarina 14 (23%), Paraná 11 (18%), and Mato Grosso do Sul 4 (7%). Positive anti-IA IHC labelling was observed in 45% of the cases, which were associated with necrotizing bronchiolitis, atelectasis, purulent bronchopneumonia and hyperemia. Moreover, type II pneumocyte hyperplasia, alveolar and bronchiolar polyp-like structures, bronchus-associated lymphoid tissue (BALT) hyperplasia and pleuritis were the significant features in negative anti-IA IHC, which were also associated with chronic lesions. There were only two cases with positive anti-PCV2 IHC and none to PRRSV. Therefore, SIV was the predominant infectious agent in the lung samples studied. The viral antigen is often absent due to the rapid progress of SI, which may explain the negative IHC results for IA (55%); therefore, IHC should be performed at the beginning of the disease. This study has shown how important a careful histological evaluation is for the diagnosis. Since 2009, a new histological feature of swine pneumonia in animals with respiratory clinical signs has been observed in samples from pigs with clinical respiratory disease submitted to SPV-UFRGS. In addition, the results proved the importance of histological evaluation for swine herd health management.

Influenza suína (IS) é uma doença altamente contagiosa, de curso rápido e pronta recuperação, causada pelo vírus influenza tipo A (SIV). Os principais sinais clínicos são tosse, febre, anorexia e baixo desenvolvimento. A doença está presente em outros países e, geralmente, está associada com outros agentes infecciosos. No Brasil, a primeira descrição ocorreu em 2011 e foi associada ao vírus H1N1 pandêmico (pH1N1). O principal objetivo deste estudo foi caracterizar as alterações histológicas em casos de doença respiratória suína sugestiva de IS e estudar a associação dessas alterações com os resultados de imuno-histoquímica (IHQ) anti-vírus da influenza A (SIV), anti-circovírus suíno tipo 2 (PCV2) e anti-vírus da síndrome reprodutiva e respiratória (PRRSV). Para tanto, foram estudadas amostras de pulmões de 60 suínos selecionadas dos materiais do arquivo do Setor de Patologia Veterinária da Universidade Federal do Rio Grande do Sul (SPV-UFRGS), de casos de doença respiratória remetidos no período de 2009 a 2010 e que apresentavam alterações histopatológicas compatíveis com pneumonia viral causada pelo SIV. Todas as amostras apresentavam pneumonia intersticial e bronquiolite necrótica muito peculiar que não eram vistas antes na rotina do nosso laboratório. Trinta e uma amostras (52%) tiveram origem no estado do Rio Grande do Sul, 14 (23%) do Paraná, 11 (18%) de Santa Catarina e quatro (7%) do Mato Grosso do Sul. A IHQ para IA confirmou a presença do agente viral em 45% das amostras analisadas. Os achados histológicos mais significativos associados à IHQ positiva para IA foram bronquiolite necrótica, atelectasia, broncopneumonia purulenta e hiperemia. Por outro lado, as alterações histológicas dos pulmões estudados, mais significativamente associadas às IHQ negativa para IA foram hiperplasia dos pneumócitos tipo II, estruturas similares a pólipos em alvéolo e bronquíolo, hiperplasia de tecido linfoide associado a brônquios (BALT) e pleurite, que são alterações associadas a processos crônicos. Somente dois casos apresentaram marcação positiva na IHQ para PCV2 e nenhum pulmão foi positivo para PRRSV. Esses resultados sugerem que as lesões histológicas encontradas no presente estudo foram, predominantemente, causadas pelo SIV. Os casos negativos de IHQ para IA (55%) podem ser explicados pela ausência do antígeno viral nos tecidos estudados. Como o curso da doença é muito rápido, o teste de IHQ é mais indicado para diagnóstico no início da doença. Este estudo possibilitou demonstrar um conjunto de novas alterações histológicas pulmonares de suínos com problemas respiratórios, observadas em amostras pulmonares enviadas ao SPV-UFRGS a partir de 2009. O presente trabalho também reforça a importância de estudos histopatológicos dos casos de campo para auxiliar na monitoria da sanidade dos rebanhos suínos.

Influenza virus A H5N1 and H1N1: features and zoonotic potential / Virus de Influenza A H5N1 y H1N1: características y potencial zoonótico / Os virus da Influenza A H5N1 e H1N1: características e potencial zoonótico

Influenza A viruses which belong to the Orthomyxoviridae family, are enveloped, pleomorphic, and contain genomes of 8 single-stranded negative-sense segments of RNA. Influenza viruses have three key structural proteins: hemagglutinin (HA), neuraminidase (NA) and Matrix 2 (M2). Both HA and NA are surface glycoproteins diverse enough that their serological recognition gives rise to the traditional classification into different subtypes. At present, 16 subtypes of HA (H1-H16) and 9 subtypes of NA (N1-N9) have been identified. Among all the influenza A viruses with zoonotic capacity that have been described, subtypes H5N1 and H1N1, have shown to be the most pathogenic for humans. Direct transmission of influenza A viruses from birds to humans used to be considered a very unlikely event but its possibility to spread from human to human was considered even more exceptional. However, this paradigm changed in 1997 after the outbreaks of zoonotic influenza affecting people from Asia and Europe with strains previously seen only in birds. Considering the susceptibility of pigs to human and avian influenza viruses, and the virus ability to evolve and generate new subtypes, that could more easily spread from pigs to humans, the possibility of human epidemics is a constant menace. A recent example was the outbreak of H1N1 influenza in 2009 that crossed species and geographical borders affecting up to 20 to 40% of the people in some parts of the world. Vaccines and control measures are continuously being developed to address a threat that every year claims human and animal lives, and makes us fear for a new and more lethal strain of the virus.

Los virus de influenza tipo A pertenecen a la familia Orthomyxoviridae, son envueltos, pleomórficos, y contienen 8 segmentos de ARN de cadena negativa. Dichos agentes poseen tres proteínas estructurales claves: Hemaglutinina (HA), Neuraminidasa (NA) y proteína de Matriz 2 (M2). La HA y la NA son glicoproteínas de superficie, que debido a su gran diversidad fueron usadas para crear la clasificación y nomenclatura de subtipos de virus de influenza, basada en la reactividad serológica contra ellas. De acuerdo con lo anterior, hasta la fecha se han identificado 16 subtipos de HA (H1-H16) y 9 subtipos de NA (N1-N9). De los virus tipo A, los denominados H5N1 y H1N1 han demostrado ser los más patógenos. El contagio directo de los virus de influenza A de las aves a los humanos se consideraba un evento raro y su dispersión se creía que era aún más limitada, percepción que ha cambiado desde 1997 y particularmente con los últimos brotes zoonóticos de influenza en Asia y Europa. Adicionalmente, si se considera que el porcino es una especie susceptible a virus de influenza provenientes de humanos y aves, y que estos agentes infecciosos tienen la capacidad de realizar un cambio antigénico al reasociarse generando así nuevos subtipos, la potencialidad de nuevas amenazas a la población humana es cada vez más tangible. Ejemplo de lo anterior es la reciente pandemia de influenza A H1N1 en el año 2009, que atravesó fronteras sin discriminación geográfica o de especie, afectando entre el 20 y el 40% de las personas en algunas partes del mundo. Vacunas y medidas de control se desarrollan en la actualidad para afrontar esta amenaza que cada año cobra vidas humanas y animales, y nos hace temer por una nueva y más mortífera epidemia en el futuro.

Os vírus da influenza A pertencem à família Orthomyxoviridae, são envolvidos, pleomórficas, e contem oito segmentos de RNA de cadeia negativa. Os vírus da influenza têm três principais proteínas estruturais: HA (hemaglutinina), NA (neuraminidase) e proteína de matriz 2M. A hemaglutinina e a neuraminidase são glicoproteínas de superfície, que dão nome a os tipos e subtipos dos vírus da Influenza até agora têm sido identificados 16 subtipos da HA (H1-H16) e nove subtipos da NA (N1-N9). Dos vírus tipo A, chamado H5N1 e H1N1 tem demostrado que são os mais patogênicos. A transmissão direta do vírus da influenza A das aves para os humanos foi considerado um evento raro e sua propagação parecia ser mais limitada, esta percepção mudou com os recentes surtos zoonóticos da influenza. Além disso, considerando que o suíno é uma espécie suscetível ao vírus da influenza de humanos e aves, e que esses agentes infecciosos são capazes de fazer uma alteração no antígeno ao associar novamente, gerando assim novos subtipos, o potencial para novas ameaças na população humana, esta tem-se tornando mais palpável. Um exemplo disso é a recente pandemia da influenza H1N1 no 2009, que atravessou as fronteiras sem discriminação geográfica ou de espécie afectando entre o 20 o 40% das pessoas em algumas partes do mundo. Vacinas e medidas de controle são atualmente desenvolvidas para tratar a pandemia que ainda hoje continua a afetando vidas humanas e animais, e o medo latente de uma nova e mais mortal ainda não chega.

Brote comunitario de influenza A H1N1 2009 en el período post-pandémico inmediato: descripción epidemiológica en una localidad aislada de la región de Aysén, Patagonia chilena / Epidemiologic description of a post-pandemic outbreak of influenza A H1N1 2009 in an isolated community of the region of Aysén, Chilean patagonia

On August 10th 2010 the World Health Organization (WHO) announced the end of the influenza A H1N1 2009 pandemic. On August 13th, three cases of influenza A H1N1 2009 from the local school were confirmed at the Hospital de Chile Chico. An epidemiological investigation was conducted in conjunction with the regional health authority (SEREMI), in order to monitor the outbreak and establish appropriate control strategies. During the study period (august 7 to 21), 304 cases of influenza-like-illness (ILI) were reported, with an incidence of 6171 cases per 100.000 in epidemiological week n° 33. Most of the affected people were 19 years old or younger (68 percent of cases). Hospitalized patients (n: 7) had a favorable outcome, without severe symptoms or need for transfer to an intensive care unit. A female patient with a congenital heart defect who had not been vaccinated was the only fatal case. The outstanding features of this post-pandemic outbreak were its intensity and the demonstration of the importance of control measures to prevent further spread of influenza A H1N1 2009 infections, in the community setting.

El 10 de agosto de 2010 la Organización Mundial de la Salud (OMS) declaró el fin de la pandemia por el virus influenza A H1N1 2009. El 13 de agosto, se confirmaron tres casos de influenza A H1N1 2009 en el Hospital de Chile Chico provenientes de la escuela local. Se inició una investigación epidemiológica en conjunto con la autoridad sanitaria regional (SEREMI) para monitorizar la evolución del brote y para implementar medidas de prevención y mitigación del contagio. Durante el período de estudio (7 al 21 de agosto) se registraron 304 casos de enfermedad tipo influenza (ETI), alcanzando una incidencia durante la semana epidemiológica 33 de 6.171 casos por 100.000 habitantes. Los menores de 19 años fueron el grupo etario más afectado (68 por ciento de los casos). Los pacientes que requirieron hospitalización (n: 7) evolucionaron favorablemente y ninguno requirió traslado a una unidad de cuidado intensivo. Sólo se consignó un caso fatal durante el brote, en una paciente con co-morbilidad cardiaca y sin vacuna. Este brote infeccioso destaca por su intensidad en el contexto del período post-pandémico e ilustra sobre la importancia de las medidas de prevención del contagio por influenza A H1N1 2009 a nivel comunitario.

Importancia de las imágenes y el diagnóstico etiológico en el paciente inmunocomprometido con afección del sistema nervioso central: Segunda parte / Importance of images and etiological diagnosis in the immunocompromised patient with central nervous system envolvement: Part II

We present the case of a 12-year-old boy with acute lymphocytic leukemia who developed pneumonia and multiple brain infarcts compatible with acute necrotic encephalitis. The infectious disease screening tests revealed influenza A H1N1 virus, Staphylococcus aureus in broncho alveolar lavage, E. coli and galactomannan antigen in blood. CNS influenza associated complications are reviewed. This case highlights the importance of magnetic resonance imaging as a diagnostic tool in the assessment of immunocompromised patients with CNS compromise and the value of brain biopsy in the final identification of an infectious disease etiology.

Escolar de 12 años de edad, con Leucemia Linfocítica Aguda en tratamiento que desarrolla una bronconeumonía bilateral, infartos cerebrales compatibles con encefalitis necrosante aguda. El estudio infectológico demostró más de una causas infecciosa que pudiera explicar su evolución destacando influenza A H1N1, Staphylococcus aureus meticilina sensible en lavado bronco alveolar, E. coli y galactomanano en sangre. Se revisa el compromiso del SNC por influenza A H1N1. Se destaca la importancia del uso de resonancia magnética nuclear al evaluar pacientes inmunocomprometidos con complicaciones neurológicas y el aporte de una biopsia cerebral en aclarar la etiología de este compromiso.

Impacto de la obesidad en pacientes con neumonía grave por virus influenza A/H1N1: estudio multicéntrico chileno / Impact of obesity with severe pneumonia by influenza A/H1N1 virus: a Chilean multicenter study

En la primera pandemia del siglo XXI por virus influenza A/H1N1, una importante proporción de paciente que desarrollaron neumonía y Falla Respiratoria Aguda (FRA) eran obesos. La obesidad ha sido propuesta como un factor de riesgo que aumenta la morbimortalidad; sin embargo, hay controversia al respecto. Objetivo: evaluar el impacto de la obesidad en complicaciones, estadía y/o mortalidad en pacientes adultos graves por virus influenza A/H1N1. Estudio observacional y multicéntrico realizado en 17 UCIs de Chile durante el periodo mayo-agosto 2009. Fueron incluidos en el estudio solo paciente con infección por virus Influenza A/H1N1 confirmada o probable. Los paciente obesos (IMC>30) fueron comparados con pacientes no obesos. Resultados: De un total de 136 pacientes incluidos en el estudio, 64 (47 por ciento) fueron obesos y de estos 13 obesos mórbidos (BMI >40). Los pacientes obesos tienen mayor frecuencia de: comorbilidades, ventilación mecánica y complicaciones. La estadía en UCI y en el hospital fue más prolongada en pacientes obesos (18,1+/-15 vs. 10,9+/-10,2, p=0,002 y 27,2+/-24,7 vs17,7 +/- 14,6, p=0,01 respectivamente). La mortalidad fue mayor en pacientes obesos (36 por ciento vs. 19,4 por ciento; OR 2,32; IC95 por ciento 1,07-5,05, p=0.035). El estudio de regresión logística encuentra que la FOM es un factor pronóstico independiente de mortalidad en pacientes obesos. Conclusiones: Los pacientes obesos con neumonía grave por virus influenza A/H1N1 tienen una mayor morbi-mortalidad y prolongación de su estadía en UCI y en el hospital. El desarrollo de FOM en pacientes obesos es un factor de mal pronóstico.

In the first pandemic of the 21st century due to influenza A/H1N1 virus, a significant proportion of patients who developed pneumonia and acute respiratory failure (ARF) were obese. Obesity has been proposed as a risk factor that increases morbidity and mortality, however, there is controversy about it. Objective: To determine the impact of obesity on complications, stay and / or mortality in adult patients with severe influenza A/H1N1 virus. Multicenter observational study conducted in 17 ICUs of Chile during the period May to August 2009. Were included only patients with influenza A/H1N1 virus infection confirmed or probable. Obese patients (BMI> 30) were compared with non obese patients. The results: Of a total of 136 patients included in the study, 64 (47 percent) were obese and of these 13 morbidly obese (BMI> 40). Obese patients have a higher frequency of: comorbidities, mechanical ventilation and complications. The stay in ICU and hospital was longer in obese patients (18.1 +/- 15 vs. 10.9 +/- 10.2, p = 0.002 and 27.2 +/- 24.7 vs17, 7 +/- 14.6, p = 0.01 respectively). Mortality was higher in obese patients (36 percent vs. 19.4 percent, OR 2.32, 95 percent CI 1.07 to 5.05, p = 0,035). The logistic regression analysis found that the MOF is an independent predictor of mortality in obese patients. Conclusions: Obese patients with severe pneumonia due to the influenza A/H1N1 virus have a high morbidity and mortality and prolonged stay in ICU and hospital. MOF development in obese patients is a poor prognostic factor.