Diversidad genética del complejo de virosis asociadas a la enfermedad del mosaico de la caña de azúcar en Tucumán, Argentina Genetic diversity of sugarcane mosaic virus complex in Tucuman, Argentina

El mosaico de la caña de azúcar es una de las enfermedades sistémicas de mayor importancia de este cultivo. El virus del mosaico de la caña de azúcar (SCMV) y el virus del mosaico del sorgo (SrMV) son los principales agentes causales de esta enfermedad. Mediante RT-PCR-RFLP (siglas del "reverse transcriptase-polymerase chain reaction"-"restriction fragment length polymorphism") y secuenciación del gen de la proteína de la cápside, se analizaron muestras de caña de azúcar con síntomas de mosaico para evaluar la presencia y estimar la diversidad genética de ambos virus en el área cañera de Tucumán. Noventa y tres por ciento de las muestras resultaron positivas para SCMV al utilizar los cebadores específicos SCMVF4/R3 y 33% de ellas exhibió el perfil RFLP de la raza E. El resto de las muestras presentó nueve perfiles diferentes que no se correspondieron con los de las razas descritas. El análisis de la secuencia indicó que 20% de las muestras de perfil RFLP desconocido presentó una alta identidad con la raza D, mientras que las muestras restantes resultaron divergentes entre sí. Mediante microscopía electrónica de transmisión, se confirmó la presencia de los típicos viriones flexuosos de los potyvirus. Asimismo, se detectó la presencia de SrMV en 90% de las muestras con los cebadores específicos y la coexistencia de ambos virus en 85% de las mismas. Mediante RFLP, se identificaron las razas M e I del virus del sorgo en 68% y 14% de las muestras, respectivamente, y en 18% de los casos se detectó coexistencia entre las razas M y H de esta virosis. Solo una de las muestras no amplificó para ninguno de los dos virus, lo que sugeriría la existencia de otro agente responsable de una sintomatología similar.Sugarcane mosaic is one of the most important systemic diseases of sugarcane. Sugarcane mosaic virus (SCMV) and Sorghum mosaic virus (SrMV) are the causal agents of the disease. Sugarcane leaves with mosaic symptoms were analysed by RT-PCR-RFLP (reverse transcriptase-polymerase chain reaction- restriction fragment length polymorphism) and the nucleotide sequences of the coat protein (CP) genes amplified to assess the presence and genetic diversity of both viruses in the sugarcane producing area in Tucumán. Using the primers SCMVR3/F4, 93% of samples were SCMV positive and 33% of them had the E strain RFLP profile, while the rest produced nine different profiles that did not match those of any known strains. Sequence analyses showed that 20% of the samples with the unknown profiles were highly identical to the SCMV D strain, while the rest differed significantly from each other. The presence of the flexuous virions typical of potyviruses was confirmed by transmission electron microscopy. Also, using the specific primers, the presence of SrMV was detected in 90% of the samples, and co-existence of both viruses was found in 85% of the samples. RFLP analysis determined the presence of SrMV strains M and I in 68% and 14% of the samples, respectively, while in approximately 18% of the cases, both M and H strains were present. No RT-PCR product was produced by either SCMV or SrMV primer pairs in one symptomatic sample, suggesting the presence of another pathogen producing similar symptomatology

Effects of pre-operative isolation on postoperative pulmonary complications after elective surgery: an international prospective cohort study an international prospective cohort study

We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care. We aimed to determine the impact of pre-operative isolation on postoperative pulmonary complications after elective surgery during the global SARS-CoV-2 pandemic. We performed an international prospective cohort study including patients undergoing elective surgery in October 2020. Isolation was defined as the period before surgery during which patients did not leave their house or receive visitors from outside their household. The primary outcome was postoperative pulmonary complications, adjusted in multivariable models for measured confounders. Pre-defined sub-group analyses were performed for the primary outcome. A total of 96,454 patients from 114 countries were included and overall, 26,948 (27.9%) patients isolated before surgery. Postoperative pulmonary complications were recorded in 1947 (2.0%) patients of which 227 (11.7%) were associated with SARS-CoV-2 infection. Patients who isolated pre-operatively were older, had more respiratory comorbidities and were more commonly from areas of high SARS-CoV-2 incidence and high-income countries. Although the overall rates of postoperative pulmonary complications were similar in those that isolated and those that did not (2.1% vs 2.0%, respectively), isolation was associated with higher rates of postoperative pulmonary complications after adjustment (adjusted OR 1.20, 95%CI 1.05–1.36, p = 0.005). Sensitivity analyses revealed no further differences when patients were categorised by: pre-operative testing; use of COVID-19-free pathways; or community SARS-CoV-2 prevalence. The rate of postoperative pulmonary complications increased with periods of isolation longer than 3 days, with an OR (95%CI) at 4–7 days or ≥ 8 days of 1.25 (1.04–1.48), p = 0.015 and 1.31 (1.11–1.55), p = 0.001, respectively. Isolation before elective surgery might be associated with a small but clinically important increased risk of postoperative pulmonary complications. Longer periods of isolation showed no reduction in the risk of postoperative pulmonary complications. These findings have significant implications for global provision of elective surgical care