Abstract INTRODUCTION: Haemagogus are mosquitoes with diurnal habits that live preferentially in forest areas. In Brazil, they are considered the primary vectors of wild yellow fever. METHODS: The ecological relationships between Haemagogus spegazzinii, the environment, and some of its activities in the semiarid region of Rio Grande do Norte were analyzed by collecting eggs with ovitraps, actively searching in tree holes, capturing adults in Shannon traps, and conducting an investigation for viral infections. RESULTS: A total of 2420 eggs, 271 immature specimens (larvae and pupae), and 206 adults were collected. Egg collection depended on rainfall and relative humidity, with oviposition occurring between January and May. Larvae were found in five plant species, including Tabebuia aurea (craibeira), with 160 larvae collected. We observed shared breeding sites between Hg. spegazzinii and the following species: Aedes albopictus, Aedes terrens, Culex spp., and Toxorhynchites theobaldi. Adults exhibited greater activity between 5 pm and 6 pm, when 191 (92.7%) specimens were captured, while only 1 (0.5%) was collected between 7 pm and 8 pm. The relationship between Hg. spegazzinii and rainfall was significant, with positive correlations with accumulated rainfall 5, 10, 15, 20, and 30 days before mosquito collection. We found that the species was infected with the DENV-2 virus. CONCLUSIONS: This work contributes new information on the bioecology of Hg. spegazzinii, with data on the main reproduction periods, oviposition, breeding sites, activity times, and the relationship between the species and meteorological variables in the Caatinga of northeastern Brazil.

Resumo OBJETIVO: relatar a experiência denominada vigi@dengue realizada no município de Natal-RN, Brasil, em out/2015-maio/2016. MÉTODOS: os indicadores entomológicos foram obtidos a partir das armadilhas de oviposição, e os indicadores epidemiológicos, das notificações no Sistema de Informação de Agravos de Notificação (Sinan-dengue) on-line, da busca ativa de casos e detecção de RNA viral (RTq-PCR) em artrópodes e amostras de soro humano; definiram-se níveis de risco baseados nesses indicadores, estabelecendo-se categorias de intervenções para cada nível. RESULTADOS: identificação precoce do surgimento de epidemia em três áreas da cidade, com orientação do trabalho de campo para áreas mais vulneráveis; Natal-RN apresentou índice de positividade de ovitrampas (IPO) de 40% e índice de densidade de ovos (IDO) de 51 ovos∕ovitrampa; identificou-se cocirculação dos arbovírus CHIKV, DENV-1 e DENV-3 em Natal-RN. CONCLUSÃO: a estratégia identificou precocemente o surgimento de epidemias localizadas; foi útil à orientação das medidas de controle para as áreas de maior risco.

Abstract OBJECTIVE: to report the vigi@dengue experience, held in the municipality of Natal-RN, Brazil, from October/2015 to May/2016. METHODS: entomological indicators were obtained from the oviposition traps, epidemiological indicators from notifications on the online Information System for Notifiable Diseases (Sinan-dengue), active search for cases and viral RNA detection (RTq-PCR) in arthropods and human serum samples; risk levels have been created based on these indicators; categories of interventions for each risk level have been established. RESULTS: early identification of epidemics in three areas of the municipality, with guidance for field work for the most vulnerable areas; the municipality presented ovitrap positivity index (OPI) of 40% and eggs density index (EDI) of 51 eggs/ovitraps; identification of CHIKV, DENV-1 and DENV-3 in Natal-RN. CONCLUSION: the strategy identified the early emergence of epidemics in specific locations; it was helpful in the guidance of control measures for the areas of major risk.

Resumen OBJETIVO: presentar la experiencia llamada vigi@dengue realizada en Natal-RN, Brasil, entre oct/2015-mai/2016. MÉTODOS: se obtuvieron los indicadores entomológicos de las trampas de oviposición y los indicadores epidemiológicos atreves de las notificaciones en el sistema Sinan-dengue online, la búsqueda activa de casos y la detección de ARN viral (RTQ-PCR) en muestras de suero humano y artrópodos; los niveles de riesgo se crearon usando estos indicadores; se han establecido categorías de intervenciones para cada nivel de riesgo. RESULTADOS: identificación temprana del aumento epidémico en tres zonas de la ciudad, con la orientación del trabajo de campo de las zonas más vulnerables; la ciudad de Natal-RN presenta índice de positividad de ovitrampas de 40% y índice de densidad de ovitrampas de 51 huevos/trampa; identificamos la co-circulación de CHIKV, DENV-1 y DENV-3 en Natal-RN. CONCLUSIÓN: la estrategia inicial identificó la aparición de epidemias localizadas y ha sido útil en la dirección de las medidas de control dirigidas a las áreas de mayor riesgo.

Resumo OBJETIVO: relatar a experiência denominada vigi@dengue realizada no município de Natal-RN, Brasil, em out/2015-maio/2016. MÉTODOS: os indicadores entomológicos foram obtidos a partir das armadilhas de oviposição, e os indicadores epidemiológicos, das notificações no Sistema de Informação de Agravos de Notificação (Sinan-dengue) on-line, da busca ativa de casos e detecção de RNA viral (RTq-PCR) em artrópodes e amostras de soro humano; definiram-se níveis de risco baseados nesses indicadores, estabelecendo-se categorias de intervenções para cada nível. RESULTADOS: identificação precoce do surgimento de epidemia em três áreas da cidade, com orientação do trabalho de campo para áreas mais vulneráveis; Natal-RN apresentou índice de positividade de ovitrampas (IPO) de 40% e índice de densidade de ovos (IDO) de 51 ovos∕ovitrampa; identificou-se cocirculação dos arbovírus CHIKV, DENV-1 e DENV-3 em Natal-RN. CONCLUSÃO: a estratégia identificou precocemente o surgimento de epidemias localizadas; foi útil à orientação das medidas de controle para as áreas de maior risco.

Abstract OBJECTIVE: to report the vigi@dengue experience, held in the municipality of Natal-RN, Brazil, from October/2015 to May/2016. METHODS: entomological indicators were obtained from the oviposition traps, epidemiological indicators from notifications on the online Information System for Notifiable Diseases (Sinan-dengue), active search for cases and viral RNA detection (RTq-PCR) in arthropods and human serum samples; risk levels have been created based on these indicators; categories of interventions for each risk level have been established. RESULTS: early identification of epidemics in three areas of the municipality, with guidance for field work for the most vulnerable areas; the municipality presented ovitrap positivity index (OPI) of 40% and eggs density index (EDI) of 51 eggs/ovitraps; identification of CHIKV, DENV-1 and DENV-3 in Natal-RN. CONCLUSION: the strategy identified the early emergence of epidemics in specific locations; it was helpful in the guidance of control measures for the areas of major risk.

Resumen OBJETIVO: presentar la experiencia llamada vigi@dengue realizada en Natal-RN, Brasil, entre oct/2015-mai/2016. MÉTODOS: se obtuvieron los indicadores entomológicos de las trampas de oviposición y los indicadores epidemiológicos atreves de las notificaciones en el sistema Sinan-dengue online, la búsqueda activa de casos y la detección de ARN viral (RTQ-PCR) en muestras de suero humano y artrópodos; los niveles de riesgo se crearon usando estos indicadores; se han establecido categorías de intervenciones para cada nivel de riesgo. RESULTADOS: identificación temprana del aumento epidémico en tres zonas de la ciudad, con la orientación del trabajo de campo de las zonas más vulnerables; la ciudad de Natal-RN presenta índice de positividad de ovitrampas de 40% y índice de densidad de ovitrampas de 51 huevos/trampa; identificamos la co-circulación de CHIKV, DENV-1 y DENV-3 en Natal-RN. CONCLUSIÓN: la estrategia inicial identificó la aparición de epidemias localizadas y ha sido útil en la dirección de las medidas de control dirigidas a las áreas de mayor riesgo.

Circulation of a new dengue virus (DENV)-3 genotype was recently described in Brazil and Colombia, but the precise classification of this genotype has been controversial. Here we perform phylogenetic and nucleotide-distance analyses of the envelope gene, which support the subdivision of DENV-3 strains into five distinct genotypes (GI to GV) and confirm the classification of the new South American genotype as GV. The extremely low genetic distances between Brazilian GV strains and the prototype Philippines/L11423 GV strain isolated in 1956 raise important questions regarding the origin of GV in South America.

A total of 4 243 049 dengue cases have been reported in Brazil between 1981 and 2006, including 5 817 cases of dengue hemorrhagic fever/dengue shock syndrome (DHF/DSS) and a total of 338 fatal cases. Although all Brazilian regions have been affected, the Northeast and Southeast regions have registered the highest number of notifications. DENV-1 and DENV-4 were isolated for the first time in the Amazon region of Brazil in 1981 and 1982. The disease became a nationwide public health problem following outbreaks of DENV-1 and DENV-2 in the state of Rio de Janeiro in 1986 and 1990, respectively. The introduction of DENV-3 in 2000, also in the state of Rio de Janeiro, led to a severe epidemic with 288 245 reported dengue cases, including 91 deaths. Virus strains that were typed during the 2002 epidemic show that DENV-3 has displaced other dengue virus serotypes and entered new areas, a finding that warrants closer evaluation. Unusual clinical symptoms, including central nervous system involvement, have been observed in dengue patients in at least three regions of the country.

En Brasil se han notificado 4 243 049 casos de dengue entre 1981 y 2006, de ellos 5 817 casos de dengue hemorrágico/síndrome de choque por dengue (DH/SCD) y un total de 338 casos mortales. A pesar de que la enfermedad ha afectado a todas las regiones brasileñas, el mayor número de casos se ha notificado en las regiones nororiental y suroriental. Los virus del dengue (DENV) 1 y 4 se aislaron por primera vez en la región amazónica de Brasil en 1981 y 1982. La enfermedad se convirtió en un problema nacional de salud pública después de los brotes de DENV-1 y DENV-2 en el Estado de Río de Janeiro en 1986 y 1990, respectivamente. La introducción del DENV-3 en 2000, también en el Estado de Río de Janeiro, llevó a una grave epidemia con 288 245 casos notificados de dengue y 91 muertes. Las cepas del virus identificadas durante la epidemia de 2002 demostraron que el DENV-3 ha desplazado a los otros serotipos y se ha expandido a nuevas zonas, algo que merece una evaluación más profunda. En los pacientes con dengue de al menos tres regiones del país se han observado síntomas clínicos atípicos, entre ellos alteraciones del sistema nervioso central.

Dengue outbreaks have occurred in several regions in Brazil and cocirculating dengue virus type 1 (DENV-1), DENV-2, and DENV-3 have been frequently observed. Dual infection by DENV-2 and DENV-3 was identified by type-specific indirect immunofluorescence assay and confirmed by reverse transcription polymerase chain reaction in a patient in Ceará with a mild disease. This is the first documented case of simultaneous infection with DENV-2 and DENV-3 in Brazil. Sequencing confirmed DENV-2 and DENV-3 (South-East/American) genotype III and (SriLanka/India), genotype III respectively.