The EEG in acute ischaemic cerebrovascular disease

The electroencephalogram (EEG) is a neurophysiological technique with high temporal resolution and sensibility in the evaluation of brain function in real time. Besides this, EEG is the gold standard for the identification of epileptogenesis and ictogenesis biomarkers. Epileptic seizures and Cerebrovascular disease are two of the most frequent neurological disorders imposing important mutual challenges. Furthermore, in recent years, stroke care has evolved remarkably and, facing a new paradigm of acute standard of care (centred on multidisciplinary Stroke Units), epileptic seizures (as stroke complications) deserve to be rethought. The EEG is an essential neurophysiological exam in the evaluation of patients with epileptic seizures, status epilepticus and/or epilepsy, both for diagnosis and classification, as well as for the establishment of a correct treatment or outcome prediction. Furthermore, EEG has been previously used in cerebrovascular disease with different purposes. However, its clinical usefulness in the differential diagnosis of transient neurological symptoms, specifically in the differentiation between a transient ischaemic attack and some epileptic seizures, and also in the diagnosis or prediction of post-stroke seizures or in post-stroke prognosis prediction, remains uncertain. In this work, we aim to use the clinical model of acute ischaemic cerebrovascular disease to study the value of EEG in the differential diagnosis of transient neurological symptoms, in the diagnosis and prediction of post-stroke seizures and epilepsy, as well as to analyse if electroencephalographic abnormalities and/or epileptic seizures are independent predictors of an anterior circulation ischaemic stroke outcome. Furthermore, since the gold standard of acute stroke care (namely intravenous alteplase treatment) is associated with a reduction of mortality and incapacity of treated patients with possible consequences in post-stroke seizure frequency, but a pro-convulsive and an epileptogenic effect of alteplase has also been described, we aim to test the hypothesis that ischaemic stroke patients treated with intravenous alteplase have a different frequency of epileptic (clinic and/or electroencephalographic) manifestations compared to non-treated patients. Different research methodologies were used in this thesis. A systematic review and meta-analysis of observational studies was performed to evaluate both the frequency of post-stroke (ictal and interictal) epileptiform activity in the EEG, and the quality of studies about this subject. Furthermore, different types of observational studies (including clinical case report, case series and cohort studies) were completed to answer relevant clinical questions. We performed a prospective longitudinal study of possible transient ischaemic attacks (TIA) patients evaluated at a tertiary centre during 36 months, with 1-3 months follow-up and also of acute anterior circulation ischaemic stroke patients, consecutively admitted to a Stroke Unit over 24 months and followed-up for one year. In both studies, patients underwent standardized clinical, diagnostic and neurophysiological assessment. A short duration (≤60 minutes) video-EEG protocol with an extended montage including 64 EEG, two electrooculogram, one electrocardiogram and at least one electromyogram channel was established. Different electroencephalographic investigation technics including visual, back-average and quantitative analysis were used in the clinical workup of patients with possible and definite, transient and established, cerebrovascular disease as tools for the differential diagnosis and for brain functional assessment, concerning not only epileptic manifestations detection and prediction but also to search for predictors of ischaemic stroke functional outcome and vital prognosis. Although epileptic seizures were the most frequent defined final diagnosis (n=13; 16.3%) in our series of 80 patients with difficult-to-diagnose transient neurological symptoms, visual inspection of EEG supported this diagnosis only in 7.5% (n=6) of patients with possible TIA. Moreover, the majority (n=6; 53.8%) of patients with the final diagnosis of epileptic seizures did not have interictal epileptiform activity in an early EEG. Furthermore, early focal slow wave activity, the most frequent EEG abnormality in this patient’s series, did not distinguished between TIA and seizure patients. Our systematic review and random-effects meta-analysis showed that the pooled frequency of post-stroke ictal and interictal epileptiform activity was 7% (95%CI: 3%-12%) and 8% (95%CI: 4%-13%) respectively. Only 2 out of 17 included studies (11.7%) attained the maximum quality score. Moreover, no study exclusively enrolled ischaemic stroke patients, highlighting the need for higher quality studies in the evaluation of epileptiform activity frequency in this type of cerebrovascular disease. Furthermore, due to detection bias, it was not possible to correlate clinical and electrographic seizures. In our prospective cohort of 151 anterior circulation acute stroke patients, we identified different post-stroke, clinical and electroencephalographic, epileptic manifestations including 22.7% (5/22) of acute symptomatic seizures that were exclusively electrographic and therefore could not otherwise be recognised. Furthermore, only EEG back-average analysis allowed the diagnosis of cortical myoclonus during intravenous alteplase perfusion in one clinical vignette included in this work and the recognition of epilepsia partialis continua as a chronic complication of this stroke type in 1.7% of patients. This original work also showed that studied clinical and EEG epileptic manifestations were not significantly different between intravenous alteplase treated and non-treated patients. This thesis work established which abnormalities of an early EEG after acute stroke (background activity asymmetry and the presence of interictal epileptiform activity) are independent predictors of epilepsy in the year after (even when adjusted for clinical and imaging stroke severity). Besides this, early (within the first 72h) post-stroke EEG features, extracted from visual (background activity diffuse slowing and asymmetry) and quantitative (such as delta-theta to alpha-beta ratio and alfa relative power) analysis were recognized as independent predictors of death or functional dependency, at hospital discharge and at 12 months after stroke. Furthermore, outcome models that incorporate delta-theta to alpha-beta ratio or alpha relative power were better than models based exclusively on clinical and imaging-related ischaemic stroke severity at hospital admission. Additionally, post-stroke acute symptomatic seizures and epilepsy were independently associated to death and to an unfavourable outcome 1 year after an acute anterior circulation ischaemic stroke, respectively. Globally, these research projects have shown the value of EEG in the current paradigm of stroke patient’s care. Furthermore, they expand the knowledge both about the EEG role as a complementary neurophysiological tool in general Neurology and about different aspects of the diagnosis and outcome of two of the most prevalent neurological disorders, Cerebrovascular Diseases and Epilepsy, in particular. Beyond the value of specific results, with this work several other research questions about EEG and seizures in ischaemic cerebrovascular disease emerge. Therefore, new possibilities of future research, ideally multicentric, clinical or translational arise

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Field and classroom initiatives for portable sequence-based monitoring of dengue virus in Brazil

This work was supported by Decit, SCTIE, Brazilian Ministry of Health, Conselho Nacional de Desenvolvimento Científico - CNPq (440685/ 2016-8, 440856/2016-7 and 421598/2018-2), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES - (88887.130716/2016-00), European Union’s Horizon 2020 Research and Innovation Programme under ZIKAlliance Grant Agreement (734548), STARBIOS (709517), Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro – FAPERJ (E-26/2002.930/2016), International Development Research Centre (IDRC) Canada (108411-001), European Union’s Horizon 2020 under grant agreements ZIKACTION (734857) and ZIKAPLAN (734548).Fundação Ezequiel Dias. Laboratório Central de Saúde Pública do Estado de Minas Gerais. Belo Horizonte, MG, Brazil / Latin American Genomic Surveillance Arboviral Network.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil / Latin American Genomic Surveillance Arboviral Network.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil Latin American Genomic Surveillance Arboviral Network.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Leônidas e Maria Deane. Laboratório de Ecologia de Doenças Transmissíveis na Amazônia. Manaus, AM, Brazil.Secretaria de Saúde do Estado de Mato Grosso do Sul. Laboratório Central de Saúde Pública. Campo Grande, MS, Brazil.Fundação Ezequiel Dias. Laboratório Central de Saúde Pública do Estado de Minas Gerais. Belo Horizonte, MG, Brazil.Laboratório Central de Saúde Pública Dr. Giovanni Cysneiros. Goiânia, GO, Brazil.Laboratório Central de Saúde Pública Professor Gonçalo Moniz. Salvador, BA, Brazil.Secretaria de Saúde do Estado da Bahia. Salvador, BA, Brazil.Laboratório Central de Saúde Pública Dr. Milton Bezerra Sobral. Recife, PE, Brazil.Laboratório Central de Saúde Pública do Estado de Mato Grosso. Cuiabá, MT, Brazil.Laboratório Central de Saúde Pública do Distrito Federal. Brasília, DF, Brazil.Fundação Ezequiel Dias. Laboratório Central de Saúde Pública do Estado de Minas Gerais. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral dos Laboratórios de Saúde Pública. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral dos Laboratórios de Saúde Pública. Brasília, DF, Brazil.Organização Pan-Americana da Saúde / Organização Mundial da Saúde. Brasília, DF, Brazil.Organização Pan-Americana da Saúde / Organização Mundial da Saúde. Brasília, DF, Brazil.Organização Pan-Americana da Saúde / Organização Mundial da Saúde. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde Coordenação Geral das Arboviroses. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde Coordenação Geral das Arboviroses. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde Coordenação Geral das Arboviroses. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde Coordenação Geral das Arboviroses. Brasília, DF, Brazil.Fundação Hemocentro de Ribeirão Preto. Ribeirão Preto, SP, Brazil.Gorgas Memorial Institute for Health Studies. Panama, Panama.Universidade Federal da Bahia. Vitória da Conquista, BA, Brazil.Laboratorio Central de Salud Pública. Asunción, Paraguay.Fundação Oswaldo Cruz. Bio-Manguinhos. Rio de Janeiro, RJ, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Coordenação Geral dos Laboratórios de Saúde Pública. Brasília, DF, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, BrazilFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, BrazilMinistério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Laboratório Central de Saúde Pública do Estado de Mato Grosso do Sul. Campo Grande, MS, Brazil.Laboratório Central de Saúde Pública do Estado de Mato Grosso do Sul. Campo Grande, MS, Brazil.Instituto de Investigaciones en Ciencias de la Salud. San Lorenzo, Paraguay.Secretaria de Estado de Saúde de Mato Grosso do Sul. Campo Grande, MS, Brazil.Fundação Oswaldo Cruz. Campo Grande, MS, Brazil.Fundação Hemocentro de Ribeirão Preto. Ribeirão Preto, SP, Brazil.Laboratório Central de Saúde Pública Dr. Giovanni Cysneiros. Goiânia, GO, Brazil.Laboratório Central de Saúde Pública Dr. Giovanni Cysneiros. Goiânia, GO, Brazil.Laboratório Central de Saúde Pública Professor Gonçalo Moniz. Salvador, BA, Brazil.Laboratório Central de Saúde Pública Dr. Milton Bezerra Sobral. Recife, PE, Brazil.Laboratório Central de Saúde Pública do Distrito Federal. Brasília, DF, Brazil.Secretaria de Saúde de Feira de Santana. Feira de Santana, Ba, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Secretaria de Saúde do Estado de Minas Gerais. Belo Horizonte, MG, Brazil.Hospital das Forças Armadas. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Brasília, DF, Brazil.Universidade Nova de Lisboa. Instituto de Higiene e Medicina Tropical. Lisboa, Portugal.University of Sydney. School of Life and Environmental Sciences and School of Medical Sciences. Marie Bashir Institute for Infectious Diseases and Biosecurity. Sydney, NSW, Australia.University of KwaZulu-Natal. College of Health Sciences. KwaZulu-Natal Research Innovation and Sequencing Platform. Durban, South Africa.University of Oxford. Peter Medawar Building. Department of Zoology. Oxford, UK.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Universidade Estadual de Feira de Santana. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brazil.Universidade de Brasília. Brasília, DF, Brazil.Universidade Salvador. Salvador, BA, Brazil.Fundação Ezequiel Dias. Belo Horizonte, MG, Brazil.Fundação Ezequiel Dias. Belo Horizonte, MG, Brazil.Fundação Ezequiel Dias. Belo Horizonte, MG, Brazil.Fundação Ezequiel Dias. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Flavivírus. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Hantaviroses e Rickettsioses. Rio de Janeiro, RJ, Brazil.Fundação Oswaldo Cruz. Instituto Leônidas e Maria Deane. Laboratório de Ecologia de Doenças Transmissíveis na Amazônia. Manaus, AM, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Faculdade de Medicina Veterinária. Belo Horizonte, MG, Brazil.Universidade Federal de Minas Gerais. Faculdade de Medicina Veterinária. Belo Horizonte, MG, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brazil.Fundação Oswaldo Cruz. Instituto Gonçalo Moniz. Salvador, BA, Brazil.Laboratório Central de Saúde Pública do Estado do Paraná. Curitiba, PR, Brazil.Laboratório Central de Saúde Pública do Estado de Rondônia. Porto Velho, RO, Brazil.Laboratório Central de Saúde Pública do Estado do Amazonas. Manaus, AM, Brazil.Laboratório Central de Saúde Pública do Estado do Rio Grande do Norte. Natal, RN, Brazil.Laboratório Central de Saúde Pública do Estado de Mato Grosso. Cuiabá, MT, Brazil.Laboratório Central de Saúde Pública Professor Gonçalo Moniz. Salvador, BA, Brazil.Laboratório Central de Saúde Pública Professor Gonçalo Moniz. Salvador, BA, Brazil.Laboratório Central de Saúde Pública Noel Nutels. Rio de Janeiro, RJ, Brazil.Instituto Adolfo Lutz. São Paulo, SP, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade de São Paulo. Instituto de Medicina Tropical. São Paulo, SP, Brazil.Universidade de São Paulo. Instituto de Medicina Tropical. São Paulo, SP, Brazil.Universidade de São Paulo. Instituto de Medicina Tropical. São Paulo, SP, Brazil.University of Oxford. Peter Medawar Building. Department of Zoology. Oxford, UK.Instituto Nacional de Enfermedades Virales Humanas Dr. Julio Maiztegui. Pergamino, Argentina.Gorgas Memorial Institute for Health Studies. Panama, Panama.Gorgas Memorial Institute for Health Studies. Panama, Panama.Gorgas Memorial Institute for Health Studies. Panama, Panama.Instituto de Salud Pública de Chile. Santiago, Chile.Instituto de Diagnóstico y Referencia Epidemiológicos Dr. Manuel Martínez Báez. Ciudad de México, México.Instituto Nacional de Enfermedades Infecciosas Dr Carlos G Malbrán. Buenos Aires, Argentina.Ministerio de Salud Pública de Uruguay. Montevideo, Uruguay.Instituto Costarricense de Investigación y Enseñanza em Nutrición y Salud. Tres Ríos, Costa Rica.Instituto Nacional de Investigacion en Salud Publica Dr Leopoldo Izquieta Pérez. Guayaquil, Ecuador.Instituto Nacional de Investigacion en Salud Publica Dr Leopoldo Izquieta Pérez. Guayaquil, Ecuador.Universidade Federal de Pernambuco. Recife, PE, Brazil.Secretaria de Saúde do Estado de Minas Gerais. Belo Horizonte. MG, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Brasília, DF, Brazil.Ministério da Saúde. Secretaria de Vigilância em Saúde. Brasília, DF, Brazil.Universidade Federal do Rio de Janeiro. Rio de Janeiro, RJ, Brazil.Universidade Federal do Rio de Janeiro. Rio de Janeiro, RJ, Brazil.Universidade Federal do Rio de Janeiro. Rio de Janeiro, RJ, Brazil.Universidade Federal do Rio de Janeiro. Rio de Janeiro, RJ, Brazil.Universidade Federal de Ouro Preto. Ouro Preto, MG, Brazil.Universidade Federal de Ouro Preto. Ouro Preto, MG, Brazil.Universidade Federal de Ouro Preto. Ouro Preto, MG, Brazil.Universidade Federal de Ouro Preto. Ouro Preto, MG, Brazil.Fundação Hemocentro de Ribeirão Preto. Ribeirão Preto, SP, Brazil.Secretaria de Saúde de Feira de Santana. Feira de Santana, BA, Brazil.Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Belo Horizonte, MG, Brazil.Brazil experienced a large dengue virus (DENV) epidemic in 2019, highlighting a continuous struggle with effective control and public health preparedness. Using Oxford Nanopore sequencing, we led field and classroom initiatives for the monitoring of DENV in Brazil, generating 227 novel genome sequences of DENV1-2 from 85 municipalities (2015–2019). This equated to an over 50% increase in the number of DENV genomes from Brazil available in public databases. Using both phylogenetic and epidemiological models we retrospectively reconstructed the recent transmission history of DENV1-2. Phylogenetic analysis revealed complex patterns of transmission, with both lineage co-circulation and replacement. We identified two lineages within the DENV2 BR-4 clade, for which we estimated the effective reproduction number and pattern of seasonality. Overall, the surveillance outputs and training initiative described here serve as a proof-of-concept for the utility of real-time portable sequencing for research and local capacity building in the genomic surveillance of emerging viruses