Dengue serotype circulation in natural populations of Aedes aegypti.

Ae. aegypti is the main vector of dengue (DENV), Zika (ZIKV), and chikungunya (CHIKV) viruses. The transmission dynamics of these arboviruses, especially the arboviral circulation in the mosquito population during low and high transmission seasons in endemic areas are still poorly understood. We conducted an entomological survey to determine dengue infection rates in Ae. aegypti and Aedes albopictus. These collections were performed in 2012-2013 during a Rio de Janeiro epidemic, just before the introduction and spread of ZIKV and CHIKV in the city. MosquiTrap© and BG-Sentinel traps were installed in three fixed and seven itinerant neighborhoods each month over ten months. Mosquitoes were in supernatants pools tested and individually confirmed for DENV infection using RT-PCR. A total of 3053 Aedes mosquitos were captured and Ae. aegypti was much more frequent (92.9%) than Ae. albopictus (6.8%). Ae. aegypti females accounted for 71.8% of captured mosquitoes by MosquitTrap© and were the only species found naturally infected with DENV (infection rate=0.81%). Only one Ae. aegypti male, collected by BG-sentinel, was also tested positive for DENV. The peak of DENV-positive mosquitoes coincided the season of the highest incidence of human cases. The most common serotypes detected in mosquitoes were DENV-3 (24%) and DENV-1 (24%), followed by DENV-4 (20%), DENV-2 (8%) and DENV-1 plus DENV4 (4%), while 95% of laboratory-confirmed human infections in the period were due to DENV-4. These contrasting results suggest silent maintenance of DENV serotypes during the epidemics, reinforcing the importance of entomological and viral surveillance in endemic areas.

Contrasting genetic structure between mitochondrial and nuclear markers in the dengue fever mosquito from Rio de Janeiro: implications for vector control.

Dengue is the most prevalent global arboviral disease that affects over 300 million people every year. Brazil has the highest number of dengue cases in the world, with the most severe epidemics in the city of Rio de Janeiro (Rio). The effective control of dengue is critically dependent on the knowledge of population genetic structuring in the primary dengue vector, the mosquito Aedes aegypti. We analyzed mitochondrial and nuclear genomewide single nucleotide polymorphism markers generated via Restriction-site Associated DNA sequencing, as well as traditional microsatellite markers in Ae. aegypti from Rio. We found four divergent mitochondrial lineages and a strong spatial structuring of mitochondrial variation, in contrast to the overall nuclear homogeneity across Rio. Despite a low overall differentiation in the nuclear genome, we detected strong spatial structure for variation in over 20 genes that have a significantly altered expression in response to insecticides, xenobiotics, and pathogens, including the novel biocontrol agent Wolbachia. Our results indicate that high genetic diversity, spatially unconstrained admixing likely mediated by male dispersal, along with locally heterogeneous genetic variation that could affect insecticide resistance and mosquito vectorial capacity, set limits to the effectiveness of measures to control dengue fever in Rio.

Relato preliminar de reflexões sobre prevenção de impasses no enfrentamento de doenças transmissíveis de origem socioambiental / Preliminary report of reflections on prevention of impasses facing diseases of social-environmental causes

O enfrentamento de doenças transmissíveis de origem socioambiental esbarra frequentemente em dificuldades de etendimento entre comunidades, poder público e cientistas, ainda que haja recursos técnicos abundantes e adequados. Esse trabalho descreve uma experiência de reflexaão sobre dificuldades encontradas pelos integrantes de um grupo interdisciplinar e multissetorial para esse enfrentamento e sugre uma metodologia baseasda em diálogo para prevenção de impasses entre setores, disciplinas e sujeitos. A metoldologia consiste em um processo, ainda em curso, baseado na consolidação de um grupo multissetorial e interdisciplinar, afeito ao diálogo. A reflexão sobre o tema gerou um anteprojeto sobre o comportamento humano ante à transmissão de doenças de veiculação hídrica em municípios do Rio de Janeiro. Outro produto foi um texto em que são sugeridos caminhos para o diálogo

Facing diseases of social-environmental causes is frequently troubled by misunderstanding among communities, public power, and scientists, inspite of the availability of abundant and appropriate technical resources. This work is based on the experience of reflections about difficulties encountered by an interdisciplinary and multisectoral group and proposes dialogue as a method to prevent impasses between sectors, disciplines and subjects. The methodology consists of a process, still in progress, based on the consolidation of a multisectoral and interdisciplinary group accustomed to dialogue. Discussions of this theme generated the proposal of a project about human behavior regarding water-borne diseases in municipal districts of Rio de Janeiro. Another product was a text suggesting methods for achieving dialogue.