Spatial Evaluation and Modeling of Dengue Seroprevalence and Vector Density in Rio de Janeiro, Brazil

Dengue is a major public health problem in many tropical regions of the world, including Brazil, where Aedes aegypti is the main vector. We present a household study that combines data on dengue fever seroprevalence, recent dengue infection, and vector density, in three neighborhoods of Rio de Janeiro, Brazil, during its most devastating dengue epidemic to date. This integrated entomological–serological survey showed evidence of silent transmission even during a severe epidemic. Also, past exposure to dengue virus was highly associated with age and living in areas of high movement of individuals and social/commercial activity. No association was observed between household infestation index and risk of dengue infection in these areas. Our findings are discussed in the light of current theories regarding transmission thresholds and relative role of mosquitoes and humans as vectors of dengue viruses

Mosquito anthropophily: implications on malaria transmission in the Northern Brazilian Amazon

Submitted by Kamylla Nascimento ([email protected]) on 2018-08-15T11:15:14Z No. of bitstreams: 1 Mosquito Anthropophily Implications on Malaria Transmission in the.pdf: 220797 bytes, checksum: 22f70d0e7248b32c9da049766f835c9d (MD5)Approved for entry into archive by Kamylla Nascimento ([email protected]) on 2018-08-15T11:27:18Z (GMT) No. of bitstreams: 1 Mosquito Anthropophily Implications on Malaria Transmission in the.pdf: 220797 bytes, checksum: 22f70d0e7248b32c9da049766f835c9d (MD5)Made available in DSpace on 2018-08-15T11:27:18Z (GMT). No. of bitstreams: 1 Mosquito Anthropophily Implications on Malaria Transmission in the.pdf: 220797 bytes, checksum: 22f70d0e7248b32c9da049766f835c9d (MD5) Previous issue date: 2010Instituto Interamericano para a Mudança Global. Bolsa de pesquisa CRN no. 048Universidade Federal de Pernambuco. Departamento de Zoologia. Recife, PE, Brasil.Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Transmissores de Hematozoários. Rio de Janeiro, RJ, Brasil.Fundação Oswaldo Cruz. Instituto Aggeu Magalhães. Departamento de Imunologia. Recife, PE, Brasil.Seasonal variation of adults and larvae of anophelines was studied during 2003 and 2004 in Roraima State, located in the Northern region of Brazilian Amazon. Species diversity increased with distance of capture to human dwellings. Greater diversity was found in extradomiciliary collections than in peridomiciliary or intradomiciliary. A significant association between Anopheles darlingi Root and An. albitarsis (s.l.) Arribálzaga (Diptera: Culicidae) breeding sites and the proximity to human dwellings was observed. Malaria Sporozoite Antigen Panel Assay (VectestTM Malaria) indicated An. albitarsis s.l. as one of the local vectors in the studied area. In this study, an index to describe the anthropophilic behavior of each anopheline species is proposed

Larvicidal activity of Ottonia anisum metabolites against Aedes aegypti: A potential natural alternative source for mosquito vector control in Brazil

Submitted by Sandra Infurna ([email protected]) on 2017-04-25T15:17:22Z No. of bitstreams: 1 nildimar_honorio_etal_IOC_2017.pdf: 285283 bytes, checksum: 258d00de4d51d5f0c1878a247188f7b5 (MD5)Approved for entry into archive by Sandra Infurna ([email protected]) on 2017-04-25T15:43:34Z (GMT) No. of bitstreams: 1 nildimar_honorio_etal_IOC_2017.pdf: 285283 bytes, checksum: 258d00de4d51d5f0c1878a247188f7b5 (MD5)Made available in DSpace on 2017-04-25T15:43:34Z (GMT). No. of bitstreams: 1 nildimar_honorio_etal_IOC_2017.pdf: 285283 bytes, checksum: 258d00de4d51d5f0c1878a247188f7b5 (MD5) Previous issue date: 2017Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto Walter Mors de Pesquisa em Produtos Naturais. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto Walter Mors de Pesquisa em Produtos Naturais. Rio de Janeiro, RJ, Brasil.Universidade Severino Sombra. Laboratório de Insetos Vetores. Vassouras, RJ, Brasil.Universidade Severino Sombra. Laboratório de Insetos Vetores. Vassouras, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório Interdisciplinar de Vigilância Entomológica em Diptera e Hemiptera. Rio de Janeiro, RJ. BrasilFundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Mosquitos Transmissores de Hematozoários. Rio e Janeiro, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Núcleo Operacional Sentinela de Mosquitos Vetores. Rio de Janeiro, RJ, Brasil.Universidade Federal do Rio de Janeiro. Centro de Ciências da Saúde. Instituto Walter Mors de Pesquisa em Produtos Naturais. Rio de Janeiro, RJ, Brasil.Universidade Severino Sombra. Laboratório de Insetos Vetores. Vassouras, RJ, Brasil / Universidade Severino Sombra. Curso de Mestrado Profissional em Ciências Ambientais. Curso de Mestrado Profissional em Ciências da Saúde. Vassouras, RJ, Brasil / Fundação Oswaldo Cruz. Instituto Oswaldo Cruz. Laboratório de Entomologia Médica e Forense. Rio de Janeiro, RJ, Brasil.Background & objectives: Aedes aegypti mosquito is the principal vector of the viruses responsible for urban yellow fever, dengue, dengue haemorrhagic fever, as well as Zika and chikungunya in Brazil. The present study was aimed to investigate the insecticidal potential of the extract and fractions of Ottonia anisum, along with special metabolites isolated from it, as natural alternatives against larvae (L3) of Ae. aegypti, vector of potentially deadly tropical infections in Brazil. Methods: The plant species O. anisum was collected in March 2015, at Xerém area, in Rio de Janeiro City, Brazil. Crude extracts and the isolated pure compounds were screened for toxicity against Ae. aegypti larvae (L3). Bioassays were performed on 20 larvae (L3) of Ae. aegypti in triplicate. The samples were dissolved in a mixture of acetone and DMSO at final concentrations of 1–200 μg/ml. The toxicity of the solutions was evaluated towards the growth and development of Ae. aegypti larvae till emergence of adults. Results: The crude hexane extract showed 100% larval mortality 24 h after treatment at a concentration of 200 μg/ ml. The bioassays using 1-butyl-3,4-methylenedioxybenzene revealed 100% mortality among L3 larvae, 24 h after the treatment at a concentration of 30 μg/ml, the LC50 recorded was 1.6 μg/ml. At concentration of 10 μg/ml, the L3 larval mortality recorded was 92%. Interpretation & conclusion: The metabolite 1-butyl-3,4-methylenedioxybenzene showed potent toxicity against Ae. aegypti larvae. This arylbutanoid agent could be used as a natural alternative adjuvant pesticide, in new compositions that would be environmentally safer

Better to Be in Bad Company than to Be Alone? <i>Aedes</i> Vectors Respond Differently to Breeding Site Quality in the Presence of Others

<div><p>This study focuses on two competing species, Aedes aegypti and Aedes albopictus (Diptera: Culicidae), both invasive mosquitoes of the New World. Context-specific competition between immature forms inside containers seems to be an important determinant of the coexistence or displacement of each species in different regions of the world. Here, competition experiments developed at low density (one, two or three larvae) and receiving four different resource food concentration, were designed to test whether Ae. albopictus and Ae. aegypti respond differently to competition, and whether competition can be attributed to a simple division of resources. Three phenotypic traits - larval development, adult survival under starvation and wing length - were used as indicators of performance. Larvae of neither species were limited by resource concentration when they were alone, unlike when they developed with competitors. The presence of conspecifics affected Ae. aegypti and Ae. albopictus, inducing slower development, reduced survival and wing length. The response to resource limitation was different when developing with heterospecifics: Ae. aegypti developing with one heterospecific showed faster development, producing smaller adults with shorter lives, while in the presence of two competitors, development increased and adults lived longer. Aedes albopictus demonstrated a better performance when developing with heterospecifics, with no loss in their development period and improved adult survival. Overall, our results suggest that response to competition can not simply be attributed to the division of resources, and that larvae of both species presented large phenotypic plasticity in their response to the presence or absence of heterospecifics and conspecifics.</p></div

Larvicidal activity of Ottonia anisum metabolites against Aedes aegypti: A potential natural alternative source for mosquito vector control in Brazil

Background & objectives: Aedes aegypti mosquito is the principal vector of the viruses responsible for urban yellow fever, dengue, dengue haemorrhagic fever, as well as Zika and chikungunya in Brazil. The present study was aimed to investigate the insecticidal potential of the extract and fractions of Ottonia anisum, along with special metabolites isolated from it, as natural alternatives against larvae (L3) of Ae. aegypti, vector of potentially deadly tropical infections in Brazil. Methods: The plant species O. anisum was collected in March 2015, at Xerém area, in Rio de Janeiro City, Brazil. Crude extracts and the isolated pure compounds were screened for toxicity against Ae. aegypti larvae (L3). Bioassays were performed on 20 larvae (L3) of Ae. aegypti in triplicate. The samples were dissolved in a mixture of acetone and DMSO at final concentrations of 1-200 μg/ml. The toxicity of the solutions was evaluated towards the growth and development of Ae. aegypti larvae till emergence of adults. Results: The crude hexane extract showed 100% larval mortality 24 h after treatment at a concentration of 200 μg/ ml. The bioassays using 1-butyl-3,4-methylenedioxybenzene revealed 100% mortality among L3 larvae, 24 h after the treatment at a concentration of 30 μg/ml, the LC50 recorded was 1.6 μg/ml. At concentration of 10 μg/ml, the L3 larval mortality recorded was 92%. Interpretation & conclusion: The metabolite 1-butyl-3,4-methylenedioxybenzene showed potent toxicity against Ae. aegypti larvae. This arylbutanoid agent could be used as a natural alternative adjuvant pesticide, in new compositions that would be environmentally safer