Molecular biology of coronaviruses: an overview of virus-host interactions and pathogenesis / Biología molecular de los coronavirus: una visión panorámica de las interacciones virus-hospedero y de la patogénesis

Abstract Coronaviruses (CoV) are enveloped, plus-strand RNA viruses that have the largest known RNA genomes and infect birds and mammals, causing various diseases. Human coronaviruses (HCoVs) were first identified in the mid-1960s and have been known to cause enteric or respiratory infections. In the last two decades, three HCoVs have emerged, including the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which initiated the ongoing pandemic. SARS-CoV-2 causes a respiratory illness that presents as a mild upper respiratory disease but may result in acute respiratory distress syndrome, multi-organ failure and can be fatal, especially when underlying comorbidities are present. Children account for a low percentage of coronavirus disease 2019 (COVID-19) cases, with seemingly less severe disease. Most pediatric patients present mild or moderate symptoms or are asymptomatic. However, some cases may be severe. Therefore, SARS-CoV-2 infection and COVID-19 in pediatric patients must be studied in detail. This review describes general features of the molecular biology of CoVs and virus-host interactions that may be implicated in the pathogenesis of SARS-CoV-2.

Resumen Los coronavirus son virus envueltos de ARN de polaridad positiva, con los genomas más grandes que se conocen. Infectan aves y mamíferos, y causan una amplia variedad de enfermedades. Los coronavirus humanos se identificaron a mediados de la década de 1960 y se sabe que causan infecciones entéricas y respiratorias. En las últimas dos décadas han emergido tres coronavirus humanos pandémicos, incluido el coronavirus 2 del síndrome agudo respiratorio grave (SARS-CoV-2) que ha causado la pandemia actual. El SARS-CoV-2 produce enfermedad respiratoria que se presenta con padecimientos moderados de las vías respiratorias altas, pero puede resultar en síndrome respiratorio agudo, falla multiorgánica y muerte, en especial en casos con morbilidad subyacente. Los casos de COVID-19 en niños representan un porcentaje bajo y con síntomas menos graves de la enfermedad. La mayoría de los pacientes pediátricos son asintomáticos o presentan enfermedad leve o moderada; sin embargo, también en niños la enfermedad puede ser grave, por lo que la infección con SARS-CoV-2 y la COVID-19 en pacientes pediátricos deben estudiarse con detalle. En esta revisión se describen las características generales de la biología molecular de los coronavirus y de las interacciones virus-hospedero que se conocen para los coronavirus humanos identificados previamente, y que podrían estar implicados en la patogénesis del SARS-CoV-2.

COVID-19 en la terapia intensiva: Análisis de la experiencia durante el primer mes de la pandemia / COVID-19 in the intensive care unit. Analysis of the experience during the first month of pandemic

Se trata de un análisis de características clínicas, hallazgos radiológicos, variables de laboratorio y mecánica respiratoria en pacientes con enfermedad por coronavirus 2019 (COVID-19) durante el primer mes de la pandemia en Buenos Aires. Es un estudio descriptivo de casos, de un solo centro. Se incluyeron todos los casos confirmados de COVID-19 internados en la unidad de terapia intensiva de adultos (UTIA) del Hospital Italiano de Buenos Aires. Todos los casos se confirmaron por reacción en cadena de la polimerasa con transcriptasa inversa. Un total de 7 pacientes con COVID-19 fueron atendidos en la UTIA. La mediana de edad fue de 71 años (intervalos intercuartílicos: 52-75), 4 hombres y 3 mujeres. Las manifestaciones clínicas más comunes fueron fiebre (7), tos (5), astenia (4) y disnea (3). Entre los hallazgos radiológicos, cinco de ellos mostraron opacidades intersticiales y un paciente consolidación pulmonar bilateral. Cinco requirieron ventilación mecánica invasiva y múltiples sesiones de decúbito prono. Ninguno murió durante la hospitalización, aunque aún tres permanecen en UCI.

This is an analysis of clinical characteristics, images findings, laboratory variables and respiratory mechanics in patients with coronavirus disease 2019 (COVID-19) during the first month of the pandemic outbreak in Buenos Aires. In this descriptive case study of a single-centre, we included all confirmed cases of COVID-19 hospitalized in intensive care unit (ICU). All cases were confirmed by reverse transcription polymerase chain reaction. A total of 7 patients with confirmed COVID-19 were referred to out ICU. The median age was 71 years (interquartile range 52-75), including 4 men and 3 women. Patients most common clinical manifestations were fever (7), cough (5), asthenia (4) and shortness of breath (3). Among the radiological findings, five of them showed interstitial opacities and one patient had bilateral pulmonary consolidation. Five required invasive mechanical ventilation and multiple prone sessions. None died during hospitalization, although three still remain in the ICU. According to imaging examination, 71.4% showed interstitial opacities and one patient bilateral consolidation. Five patients required invasive mechanical ventilation and multiple prone sessions. None of them died during hospitalization, although three still remain in the ICU.

Imaging findings in COVID-19 pneumonia

The coronavirus disease (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in Wuhan city and was declared a pandemic in March 2020. Although the virus is not restricted to the lung parenchyma, the use of chest imaging in COVID-19 can be especially useful for patients with moderate to severe symptoms or comorbidities. This article aimed to demonstrate the chest imaging findings of COVID-19 on different modalities: chest radiography, computed tomography, and ultrasonography. In addition, it intended to review recommendations on imaging assessment of COVID-19 and to discuss the use of a structured chest computed tomography report. Chest radiography, despite being a low-cost and easily available method, has low sensitivity for screening patients. It can be useful in monitoring hospitalized patients, especially for the evaluation of complications such as pneumothorax and pleural effusion. Chest computed tomography, despite being highly sensitive, has a low specificity, and hence cannot replace the reference diagnostic test (reverse transcription polymerase chain reaction). To facilitate the confection and reduce the variability of radiological reports, some standardizations with structured reports have been proposed. Among the available classifications, it is possible to divide the radiological findings into typical, indeterminate, atypical, and negative findings. The structured report can also contain an estimate of the extent of lung involvement (e.g., more or less than 50% of the lung parenchyma). Pulmonary ultrasonography can also be an auxiliary method, especially for monitoring hospitalized patients in intensive care units, where transfer to a tomography scanner is difficult.

Concordance of chest ct and nucleic acid testing in diagnosing coronavirus disease outside its district of origin (Wuhan, China)

OBJECTIVES: This study aimed to determine the concordance between CT and nucleic acid testing in diagnosing coronavirus disease (COVID-19) outside its district of origin (Wuhan, China). METHODS: Twenty-three consecutive patients with COVID-19, confirmed by nucleic acid testing, were enrolled from two designated hospitals outside the district of disease origin. We collected clinical, laboratory, and CT data and assessed the concordance between CT manifestations and nucleic acid test results by comparing the percentage of patients with and without abnormal CT findings. Furthermore, using Chi-square tests, we analyzed the differences in CT manifestations between patients with and without an exposure history or symptoms. RESULTS: Multiple ground-glass opacities (GGOs), with or without consolidation, were observed on the initial CT scans of 19 patients (82.6%), whereas the remaining 4 (17.4%) showed no CT abnormalities, indicating that the initial chest CT findings were not entirely concordant with the nucleic acid test results in diagnosing COVID-19. Among the latter 4 patients, we observed multiple GGOs with and without consolidation in 2 patients on the follow-up chest CT scans taken on days 7 and 14 after admission, respectively. The remaining 2 patients showed no abnormalities on the follow-up CT scans. Furthermore, abnormal CT findings were found more frequently in patients who had been exposed to COVID-19 in its district of origin than in those who had not been exposed and in symptomatic patients than in asymptomatic patients (all p<0.05). CONCLUSIONS: Patients with positive results on nucleic acid testing may or may not have the abnormal CT manifestations that are frequently found in symptomatic patients with a history of exposure to the district of COVID-19 origin.

Abdominal symptoms as initial manifestation of COVID-19: a case series / Sintomas abdominais como manifestação inicial da COVID-19: uma série de casos

ABSTRACT The COVID-19 became a pandemic in early 2020. It was found, at first, that the main manifestations of this new virus occur through respiratory and constitutional symptoms. Therefore, chest tomography was elected as the best imaging test to assess the extent of pulmonary involvement and as a good prognostic predictor for the disease. However, as new studies were produced, the gastrointestinal involvement of COVID-19 becomes more evident, with reports from patients who manifested mainly or only gastrointestinal symptoms in the course of the disease. Thus, in some cases, the initial investigation is carried out at the emergency department with an abdominal computed tomography. We report a case series of ten patients who came to the emergency department of our institution with a chief gastrointestinal complaint, and were initially submitted to an abdominal computed tomography as the first investigation. Although most of the patients did not have significant changes in the abdominal images, most reported patients had pulmonary findings visualized at the lung bases, which were later designated as typical COVID-19 pulmonary findings on chest computed tomography. Only one patient had atypical COVID-19 lung changes on chest computed tomography. All patients had a positive real-time polymerase chain reaction for COVID-19. It is imperative to alert radiologists, especially abdominal radiologists, with the possibility of COVID-19 isolated gastrointestinal symptoms. Besides, it must become a habit to radiologists to assess the pulmonary basis on abdominal scans, a site commonly affected by the new coronavirus.

RESUMO A COVID-19 foi declarada uma pandemia no início de 2020. Constatou-se, inicialmente, que as principais manifestações desse novo vírus ocorrem por meio de sintomas respiratórios e constitucionais. A tomografia do tórax foi eleita o exame de imagem para avaliar a extensão do comprometimento pulmonar e como um fator preditivo do prognóstico para a doença. No entanto, à medida que novos estudos são produzidos, o envolvimento gastrointestinal da COVID-19 torna-se mais evidente, com relatos de pacientes que manifestaram principalmente ou apenas sintomas gastrointestinais no decorrer da doença. Em alguns casos, a investigação inicial é realizada no pronto-socorro, com tomografia computadorizada do abdome. Relatamos uma série de casos de dez pacientes que compareceram ao serviço de emergência da instituição com uma queixa principal gastrointestinal e foram submetidos inicialmente a uma tomografia computadorizada de abdome como primeira investigação. Embora a maioria dos pacientes não tenha apresentado alterações significativas nas imagens abdominais, eles apresentaram achados pulmonares visualizados nas bases pulmonares, que depois foram caracterizadas como achados pulmonares típicos de COVID-19 nas tomografias de tórax subsequentes. Apenas um paciente apresentou achados atípicos para COVID-19 na tomografia. Todos os pacientes tiveram reação em cadeia da polimerase em tempo real positiva para o novo coronavírus. É muito importante alertar os radiologistas, principalmente os radiologistas abdominais, da possibilidade de sintomas gastrointestinais isolados no contexto da COVID-19. Além disso, deve ser um hábito para todos os radiologistas avaliar as bases pulmonares nas tomografias de abdome, local comumente afetado pela COVID-19.

Family COVID-19 cluster analysis of an infant without respiratory symptoms

Abstract Diagnosing cases of coronavirus disease (COVID-19) with only non-respiratory symptoms has been challenging. We reported the diagnosis of a child who tested positive for COVID-19 with abdominal pain/diarrhea and tracked his family cluster. One member of the family tested positive for COVID-19 on real-time reverse-transcription polymerase chain reaction assay and three other family members had anti-SARS-CoV-2 antibodies.

COVID-19 and acute myocarditis: current literature review and diagnostic challenges

SUMMARY INTRODUCTION In the current literature, there has been an upsurge of cases of COVID-19-induced acute myocarditis. In this case-based review, we aimed to describe the clinical characteristics, imaging findings, and in-hospital course of acute myocarditis. In addition, the limitations of the myocarditis diagnosis were discussed since only fulminant myocarditis cases have been mentioned in the current literature. METHODS We performed a review of the literature of all patients who were diagnosed with COVID-19-induced acute myocarditis using the databases of PubMed, Embase, and the Cochrane. RESULTS 16 case reports were found to be related to COVID-19-induced acute myocarditis. We observed that the ECG findings in most of the COVID-19 patients were non-specific, including diffuse ST-segment elevation, non-specific intraventricular conduction delay, sinus tachycardia, and inverted T-waves in anterior leads. Echocardiographic findings of COVID-19-induced acute myocarditis patients ranged from preserved left ventricular ejection fraction (LVEF) without segmental abnormalities to reduced LVEF with global hypokinesia. Interestingly, a few patients with COVID-19-induced acute fulminant myocarditis were steroid-responsive and had an amelioration with glucocorticoid and immunoglobulin therapy. CONCLUSION Despite the COVID-19 pandemic worldwide, a limited number of cases has been shared in the current literature. There are a lot of difficulties in the differential diagnosis of acute myocarditis in the context of COVID-19.

RESUMO INTRODUÇÃO Na literatura atual, houve um aumento dos casos apresentados com doença coronavírus de 2019 (COVID-19) induzida por miocardite aguda. Nesta revisão baseada em casos, buscamos descrever as características clínicas, achados de imagem e curso hospitalar de miocardite aguda. Além disso, as limitações em relação ao diagnóstico de miocardite foram discutidas, uma vez que apenas casos de miocardite fulminante foram mencionados na literatura atual. MÉTODOS Fizemos uma revisão da literatura de todos os pacientes diagnosticados com miocardite aguda induzida por COVID-19 com a utilização das bases de dados PubMed, Embase e Cochrane. RESULTADO Dezesseis casos relatados estão relacionados com a miocardite aguda induzida pela COVID-19. Observamos que os achados de ECG na maioria dos pacientes com COVID-19 não eram específicos, incluindo elevação difusa do segmento ST, atraso não específico da condução intraventricular, taquicardia sinusal e ondas T invertidas em pistas anteriores. Os resultados ecocardiográficos de doentes com miocardite aguda COVID-19 variaram entre a fração de ejeção ventricular esquerda preservada (LVEF) sem anomalias segmentais e a LVEF reduzida com hipocinésia global. Curiosamente, alguns pacientes com COVID-19 induzidos à miocardite aguda fulminante eram sensíveis aos esteroides e tinham uma melhoria com glucocorticoides e terapia com imunoglobulina. CONCLUSÃO Apesar da pandemia de COVID-19 em todo o mundo, um número limitado de casos tem sido compartilhado na literatura atual. Há muitas dificuldades para o diagnóstico diferencial de miocardite aguda no contexto da COVID-19.

The diagnostic process of covid-19 in the emergency department: laboratory and imaging methods

SUMMARY OBJECTIVES The 2019 Novel coronavirus disease puts a serious burden on the health system. Therefore, the detection of particularly serious patients at an early stage is extremely important in terms of controlling the outbreak and improving the prognosis. We investigated the role of inflammatory markers studied in patients suspected of COVID-19 at an emergency department in predicting PCR and CT results. METHODS This retrospective study was carried out with 133 patients who were admitted between 13 March and 1st April 2020 with suspicion of COVID-19. The patients were divided into four groups according to CT and RT-PCR results and evaluated. RESULTS Considering all patients, no specific findings were found in the hematological and biochemical values of patients in the laboratory analyses. Although all of the results remained within the reference range, there was a significant difference in white blood cell, neutrophil, platelet, and lymphocyte values when the groups were compared [p = 0.000; p = 0.004; p = 0.022; p = 0.023]. CONCLUSION Laboratory is not specific enough in the pre-diagnosis. In addition, this result does not alter with PCR or CT positivity. However, minimal changes observed in laboratory results may be partially guiding in patients in whom both PCR and CT are positive.

RESUMO OBJETIVOS A nova doença de coronavírus de 2019 coloca um fardo sério para o sistema de saúde. Portanto, a detecção de pacientes especialmente graves em um estágio inicial é extremamente importante em termos de controle do surto e melhoria do prognóstico. Investigamos o papel dos marcadores inflamatórios estudados em pacientes suspeitos de COVID-19 no pronto-socorro na previsão de resultados de PCR e CT. MÉTODOS Este estudo retrospectivo foi realizado entre 133 pacientes que foram admitidos entre 13 de março e 1o de abril de 2020 com suspeita de COVID-19. Os pacientes foram divididos em quatro grupos de acordo com os resultados da TC e RT-PCR e avaliados. RESULTADOS Considerando todos os pacientes, não foram encontrados achados específicos nos valores hematológicos e bioquímicos dos pacientes em análises laboratoriais. Embora todos os resultados tenham permanecido dentro do intervalo de referência, houve uma diferença significativa nos valores de glóbulos brancos, neutrófilos, plaquetas e linfócitos quando os grupos foram comparados [p = 0,000; p = 0,004; p = 0,022; p = 0,023]. CONCLUSÃO O laboratório não é suficientemente específico no pré-diagnóstico. Além disso, este resultado não se altera com a positividade para PCR ou CT. No entanto, alterações mínimas observadas nos resultados laboratoriais podem ser parcialmente norteadoras em pacientes com PCR e CT positivos.

Detecção de coronavírus em amostras de fezes diarreicas de búfalos ( Bubalus bubalis ) criados no Estado de São Paulo / Detection of coronavirus in diarrhea samples from water buffaloes ( Bubalus bubalis ) raised in the State of São Paulo, Brazil

A diarreia neonatal pode ser consequência de infecções bacterianas, endoparasitarárias e virais. Enquanto esses agentes virais são extensamente estudados nos rebanhos bovinos, faltam informações sobre a importância destes para os rebanhos bubalinos brasileiros. O objetivo deste trabalho foi avaliar a presença de rotavírus e coronavírus em amostras de fezes diarreicas de búfalos (Bubalus buballis) criados em oito propriedades localizadas em Pariquera-açu, Registro, Pirassununga, Dourado, São João da Boa Vista e Congonhas, Estado de São Paulo. Foram coletadas 40 amostras de fezes diarreicas de bezerros búfalos (Bubalus bubalis). A detecção de coronavírus foi realizada pela nested-PCR, enquanto que a detecção de rotavírus foi realizada pela Eletroforese em Gel de Poliacrilamida (PAGE) com coloração com nitrato de prata. Enquanto rotavírus não foi identificado, duas amostras (2/40, 5,0%) foram positivas para coronavírus. Embora no presente trabalho tenha havido baixa detecção de coronavírus e a ausência de rotavírus nos rebanhos estudados, a possível interferência desses vírus no desenvolvimento dos quadros diarreicos não deve ser descartada. Considerando o escasso material encontrado na literatura a respeito da diarreia em bezerros búfalos, principalmente aquele relativo ao coronavírus, nossos resultados são um incentivo para que novos estudos sejam realizados para impulsionar o desenvolvimento da bubalinocultura em nosso país.(AU)

Neonatal diarrhea can be a consequence of bacterial, endoparasite and viral infections. Although virus involved in diarrhea is frequently studied in cattle herds, there is lack of studies in Brazilian buffalo herds. The aim of this study was evaluate the presence of rotavirus and coronavirus in diarrhea samples of buffaloes (Bubalus buballis) raised on eight farms in Pariquera-açu, Registro, Pirassununga, Dourado, São João da Boa Vista e Congonhas, State of São Paulo, Brazil. We collected 40 diarrhea samples from water buffalo calves. While coronavirus was detected using nested polymerase chain reaction, rotavirus was detected using Polyacrylamide Gel Electrophoresis (PAGE) with silver stain. Rotavirus was not detected, while two samples (2/40, 5.0%) were positive for coronavirus. Although we did not detect rotavirus, a low percentage of coronavirus was observed; possible interference of these viruses in the development of diarrhea should not be discarded. Considering the lack of literature about diarrhea in water buffalo calves, particularly the one related with coronavirus, our results encourage new studies to enhance buffalo health in our country.(AU)

Human Coronavirus in the 2014 Winter Season as a Cause of Lower Respiratory Tract Infection

PURPOSE: During the late autumn to winter season (October to December) in the Republic of Korea, respiratory syncytial virus (RSV) is the most common pathogen causing lower respiratory tract infections (LRTIs). Interestingly, in 2014, human coronavirus (HCoV) caused not only upper respiratory infections but also LRTIs more commonly than in other years. Therefore, we sought to determine the epidemiology, clinical characteristics, outcomes, and severity of illnesses associated with HCoV infections at a single center in Korea. MATERIALS AND METHODS: We retrospectively identified patients with positive HCoV respiratory specimens between October 2014 and December 2014 who were admitted to Severance Children’s Hospital at Yonsei University Medical Center for LRTI. Charts of the patients with HCoV infection were reviewed and compared with RSV infection. RESULTS: During the study period, HCoV was the third most common respiratory virus and accounted for 13.7% of infections. Coinfection was detected in 43.8% of children with HCoV. Interestingly, one patient had both HCoV-OC43 and HCoV-NL63. Mild pneumonia was most common (60.4%) with HCoV, and when combined with RSV, resulted in bronchiolitis. Two patients required care in the intensive care unit. However, compared with that of RSV infection, the disease course HCoV was short. CONCLUSION: Infections caused by HCoVs are common, and can cause LRTIs. During an epidemic season, clinicians should be given special consideration thereto. When combined with other medical conditions, such as neurologic or cardiologic diseases, intensive care unit (ICU) care may be necessary.

Hospital outbreak of MERS

A cluster of MERS-CoV cases was reported from a university hospital in Riyadh, Saudi Arabia in recent time. A total of 18 laboratory-confirmed case of Middle East respiratory syndrome [MERS], including one related death was reported from this cluster. Most of the cases were asymptomatic and were detected following an active screening of close contacts of the index patient. A total of 12 asymptomatic health care workers were identified from this cluster

Detection of respiratory viruses by real-time polymerase chain reaction in outpatients with acute respiratory infection

Viruses are the major contributors to the morbidity and mortality of upper and lower acute respiratory infections (ARIs) for all age groups. The aim of this study was to determine the frequencies for a large range of respiratory viruses using a sensitive molecular detection technique in specimens from outpatients of all ages with ARIs. Nasopharyngeal aspirates were obtained from 162 individuals between August 2007-August 2009. Twenty-three pathogenic respiratory agents, 18 respiratory viruses and five bacteria were investigated using multiplex real-time reverse transcriptase polymerase chain reaction (RT-PCR) and indirect immunofluorescence assay (IIF). Through IIF, 33 (20.4%) specimens with respiratory virus were recognised, with influenza virus representing over half of the positive samples. Through a multiplex real-time RT-PCR assay, 88 (54.3%) positive samples were detected; the most prevalent respiratory viral pathogens were influenza, human rhinovirus and respiratory syncytial virus (RSV). Six cases of viral co-detection were observed, mainly involving RSV. The use of multiplex real-time RT-PCR increased the viral detection by 33.9% and revealed a larger number of respiratory viruses implicated in ARI cases, including the most recently described respiratory viruses [human bocavirus, human metapneumovirus, influenza A (H1N1) pdm09 virus, human coronavirus (HCoV) NL63 and HCoV HKU1].

Research of Viral Agent in Free-living Pigeon Feces (Columba livia) in the City of São Paulo, SP, Brazil, for Transmission Electron Microscopy / Investigación de Agentes Virales en Heces de Palomas de Vida Libre (Columba livia) en la Ciudad de São Paulo, SP, Brasil, Através de Miscroscopía Electrónica de Transmisión

The pigeon feces are vehicle of diseases both for humans and other animal species. In these birds, the most important viral diseases of the digestive tract are transmitted by the paramyxovirus, adenovirus and coronavirus. Avian paramyxoviruses have been isolated from a variety of species of free living and domestic birds worldwide, with several symptoms and clinical signs and economic losses. Paramyxoviruses belong to the Paramyxoviridae family and Avulovirus genus that includes nine serotypes (APMV 1 to 9). Avian adenoviruses belong to the Adenoviridae family and Aviadenovirus genus. In pigeons, cause classical adenovirosis and necrotizing hepatitis. The respiratory and enteric tracts are common targets of coronavirus. They belong to the Coronaviridae family and to 3a and 3c groups. In this study, we described the presence of viral agents in free-living pigeon feces (Columba livia) from the city of São Paulo, Brazil. The feces were processed by negative staining technique (rapid preparation) for transmission electron microscopy. In this technique paramyxoviruses particles, pleomorphic, roughly spherical or filamentous, measuring 100 to 500 nm of diameter containing an envelope covered by spikes, with characteristic helical herring-bone-like nucleocapsid, measuring 15 to 20 nm in diameter, were visualized in 45 (79 percent) out of 57 feces samples. In 2 (3.5 percent) samples, paramyxovirus and adenovirus particles were simultaneously visualized. Adenovirus particles were isometric, spherical, characterized as "complete "or" empty ", measuring between 70 and 90 nm in diameter. Paramyxovirus and coronavirus particles were detected in 3 (5.2 percent) samples. Coronaviruses were pleomorphic with a diameter of 75-160 nm containing a solar corona-shaped envelope, with projections of approximately 20 nm of diameter. Seven (12.3 percent) samples were negative for viral particles.

Los heces de las palomas constituyen vehículos de enfermedades importantes, tanto para el Hombre como para otras especies animales. En estas aves, las enfermedades virales más importantes del tracto digestivo son transmitidas por los paramixovirus, adenovirus y coronavirus. Paramixovirus aviario, en todo el mundo, ha sido aislado de una variedad de especies de vida libre y de aves domésticas, que causan variados síntomas y señales clínicas con pérdidas económicas. El Paramixovirus pertenece a la familia Paramyxoviridae y al género Avulavirus que incluye nueve serotipos (APMV 1 a 9). Adenovirus aviario pertenece al género de la familia Adenoviridae y género Aviadenovirus. En las palomas, causan la adenovirosis clásica y la hepatitis necrotizante. El tracto respiratorio y entérico son los albos comunes de los coronavirus. Ellos pertenecen a la familia Coronaviridae y a los grupos 3a y 3c. En este trabajo, se describe la presencia de agentes virales en las heces de palomas de vida libre (Columba livia) en la ciudad de São Paulo, Brasil. Las heces se procesaron para la técnica de microscopía electrónica de transmisión, a través de la técnica de contrastación negativa (preparación rápida). A través de esta técnica fueron visualizadas las partículas de paramixovirus, pleomórficas, más o menos esféricas o filamentosas, de 100 a 500 nm de diámetro que contiene un envoltorio cubierto con espículas, con nucleocapside con características helicoidales, midiendo de 15 a 20 nm de diámetro en 45 (79 por ciento) de 57 muestras. En 2 (3,5 por ciento) muestras, fueron observadas simultáneamente partículas de paramixovirus y de adenovirus. Las partículas de adenovirus eran isométricas, esféricas, caracterizadas como “completa " o “vacía ", midiendo entre 70 y 90 nm de diámetro. Fueron analizadas en tres muestras (5,2 por ciento) las partículas de paramixovirus y coronavirus. Los coronavirus son pleomórficos, con un diámetro de 75 a 160 nm, que contiene un capa en forma de corona solar con proyecciones de aproximadamente 20 nm de diámetro. Siete (12,3 por ciento) muestras fueron negativas para las partículas virales.

Detection of coronavirus in capybaras (Hydrochoeris hydrochaeris) by transmission electron microscopy in São Paulo, Brazil / Detección de coronavirus in capybaras (Hydrochoeris hydrochaeris) por microscopía electrónica de transmisión en São Paulo, Brasil

Coronaviruses are enveloped, positive-stranded RNA, belongs to the Nidovirales order, Coronaviridae family and are classified into three groups. Groups 3a and 3c comprising the avian coronaviruses. They are worldwide in distribution and can cause respiratory, enteric and in some cases hepatitis and neurological diseases in a wide variety of animals, resulting in economic losses to breeders and breeding. In this study, we describe an outbreak of diarrhea in a herd of capybaras found in the city of Piracicaba, São Paulo, Brazil. The animals had sudden symptoms of anorexia, profuse and watery diarrhea, yellowish or greenish, dehydration, weight loss, sharp and twisting of limbs leading to death in less than a week, mostly weaned and with an age of three months. A total of 59 stool samples and 10 fragments of small intestine were processed for negative staining technique (rapid preparation). By transmission electron microscope a large number of particles with morphology similar to coronavirus, pleomorphic, rounded or elongated features with radial projections form a corona and measuring 80-140 nm in diameter, was visualized in all samples analyzed. The technique was extremely useful for rapid viral diagnosis in the affected animals.

Coronavirus están envueltos en una cadena positiva de ARN, (orden Nidovirales, familia Coronaviridae) y se clasifican en tres grupos. Grupos que integran la tercera 3c y los coronavirus aviario. Se distribuyen por todo el mundo y pueden causar enfermedades respiratorias, entéricas y, en algunos casos, hepatitis y enfermedades neurológicas en una amplia variedad de animales, resultando en pérdidas económicas a la ganadería y los criadores. En este trabajo se describe un brote de diarrea en un rebaño de capibaras en la ciudad de Piracicaba, São Paulo, Brasil. Los animales presentaron súbitamente, los síntomas de anorexia, diarrea, profusa y acuosa, de color amarillento o verdoso, deshidratación, pérdida de peso, agudo, torsión de los miembros y la muerte en menos de una semana, en su mayoría con tres meses de edad. Un total de 59 muestras de heces y 10 trozos de intestino delgado se procesaron por la técnica de contraste negativo (preparación rápida). En todas las muestras analizadas, al microscopio electrónico de transmisión se visualizó un gran número de partículas con morfología similar a los coronavirus, pleomórficas, con características redondeadas o alargadas con proyecciones radiales en forma de corona midiendo de 80-140 nm de diámetro. La técnica es sumamente útil para el diagnóstico rápido de virus en animales afectados.

A coronavirus detected in the vampire bat Desmodus rotundus

This article reports on the identification of a group 2 coronavirus (BatCoV DR/2007) in a Desmodus rotundus vampire bat in Brazil. Phylogenetic analysis of ORF1b revealed that BatCoV DR/2007 originates from a unique lineage in the archetypical group 2 coronaviruses, as described for bat species elsewhere with putative importance in Public Health.