Living with 'difference': growing up Chinese in white Australia

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Bionomics of Culex quinquefasciatus within urban areas of Rio de Janeiro, Southeastern Brazil

OBJECTIVE: To evaluate density, parity rates, daily survival and longevity of natural populations of Culex quinquefasciatus in three neighborhoods with distinct socio-economic and infrastructure profiles. METHODS: Mosquito collections of the Culex quinquefasciatus species were performed weekly during two four month periods, from August to November 2008 (spring) and March to June 2009 (fall), in a favela (slum), a suburban area and a middle class area of Rio de Janeiro, Southeastern Brazil. Collections were performed with backpack aspirators, in 20 randomly selected houses in each area per week, during 15-20 minutes per house. Ovaries were removed from captured females and classified as initial, intermediary or final stage. Furthermore, females were dissected for determination of parity based on the condition of the tracheal system. Mosquito survival rate and longevity were estimated on a per month basis for each neighborhood. RESULTS: We collected a total of 2,062 Culex quinquefasciatus, but monthly vector density was not correlated with temperature and rainfall. We dissected the ovaries of 625 Culex quinquefasciatus, and overall, there was a higher proportion of nulliparous females during the dryer months, while gravid females were more frequent in rainy months. In the middle class neighborhood, the parity rate reached up to 93.75% with survivorship of 0.979. Lower parity and survival rates were obtained in the suburban area (as low as 36.4% parity and 0.711 daily survival). Up to 84.7% of Culex quinquefasciatus females could survive the eight day period needed to complete West Nile Virus incubation. CONCLUSIONS: The survival rate of Culex quinquefasciatus varied significantly between the neighborhoods. This suggests that vectorial capacity and disease transmission risk may vary greatly between different urban areas, which is potentially useful information for vector control programs.

PROTECÇÃO INDIVIDUAL À PICADA DE MOSQUITOS: Avaliação Laboratorial e no Campo do Efeito Repelente de Vestuário Tratado com Insecticidas ou Repelentes

RESUMO O controlo vectorial representa uma parte importante da estratégia global actual para a prevenção das principais doenças transmitidas por insectos, como a malária, a febre de dengue ou do West Nile. Uma das vertentes do controlo vectorial é aquela que se associa à protecção individual dos hospedeiros contra a picada de insectos. É no âmbito desta problemática que surge o estudo aqui apresentado. Este teve como um dos objectivos testar em laboratório a eficácia de três compostos diferentes (permetrina, DEET e citronela) contra a picada de mosquitos Anopheles stephensi Liston, 1901, quando aplicados a tecidos de algodão. Com base neste estudo laboratorial, seleccionaram-se os tecidos mais eficientes que foram testados no terreno, na área da Comporta, em ensaios simuladores de uma situação real. Os resultados foram complementados com alguns ensaios preliminares efectuados em laboratório com a espécie Culex theileri Teobald, 1903. Nos primeiros ensaios laboratoriais, tecidos impregnados com permetrina mostraram induzir uma repelência mais eficaz do que tecidos com DEET e citronela micro-encapsulados. O efeito de repelência dos tecidos com permetrina manteve-se, mesmo quando estes foram sujeitos a vários ciclos de lavagem. No entanto, os ensaios de repelência/protecção efectuados no campo demonstraram que a eficácia do tecido impregnado com permetrina é afectada pelo número de lavagens. Testes laboratoriais realizados com Cx. theileri, a espécie mais abundante da área da Comporta, apontam para que a discrepância observada entre os resultados das experiências laboratoriais e de campo possa estar associada a um comportamento diferencial das espécies envolvidas nos dois tipos de ensaio. Em conclusão, embora o uso de vestuário tratado com microcápsulas de repelentes seja um método promissor na protecção contra as picadas de insectos, este terá de beneficiar de algum investimento futuro para que possa vir a ser considerado uma estratégia válida no controlo vectorial a larga escala. Há que melhorar o modo de incorporação e apresentação do composto activo nos tecidos de modo a obter-se um efeito repelente mais efectivo e prolongado e a procura de repelentes naturais, indutores de menor toxicidade e mais repelência, deve ser continuada.

ANTIGENIC RELATEDNESS OF SELECTED FLAVIVIRUSES: STUDY WITH HOMOLOGOUS AND HETEROLOGOUS IMMUNE MOUSE ASCITIC FLUIDS

The antigenic relationship of 9 flaviviruses, Yellow fever (YF) , Wesselsbron (WSL) , Uganda S (UGS) , Potiskum (POT), West Nile (WN) , Banzi (BAN) , Zika (ZK) , Dengue type 1 (DEN-1) and Dengue type 2 (DEN-2), was assessed by cross-haemagglutination-inhibition (Cross-HI) and cross-complement fixation (Cross-CF) reactions between each of the viruses and their homologous immune mouse ascitic fluids. Titre ratios were calculated using the heterologous and homologous titres. Cross-CF reactions revealed wider antigenic variations among viruses than Cross-HI reactions. There was no significant antigenic variation between WSL, POT and YF viruses using either of those methods. However, definite differences in antigenicity were observed between them and UGS, BAN and ZK viruses. There were no significant differences between UGS, BAN and ZK or between DEN-1 and DEN-2. The serological relationship among flaviviruses is important in establishing diagnosis and epidemiology of these infections in Africa.

Molecular characterization of two rocio flavivirus strains isolated during the encephalitis epidemic in são paulo state, brazil and the development of a one-step rt-pcr assay for diagnosis

Rocio virus (ROCV) was responsible for an explosive encephalitis epidemic in the 1970s affecting about 1,000 residents of 20 coastland counties in São Paulo State, Brazil. ROCV was first isolated in 1975 from the cerebellum of a fatal human case of encephalitis. Clinical manifestations of the illness are similar to those described for St. Louis encephalitis. ROCV shows intense antigenic cross-reactivity with Japanese encephalitis complex (JEC) viruses, particularly with Ilheus (ILHV), St. Louis encephalitis, Murray Valley and West Nile viruses. In this study, we report a specific RT-PCR assay for ROCV diagnosis and the molecular characterization of the SPAn37630 and SPH37623 strains. Partial nucleotide sequences of NS5 and E genes determined from both strains were used in phylogenetic analysis. The results indicated that these strains are closely related to JEC viruses, but forming a distinct subclade together with ILHV, in accordance with results recently reported by Medeiros et al. (2007).

Emergent arboviruses in Brazil

Brazil is a large tropical country (8,514,215km²) with 185,360,000 inhabitants. More than one third of its territory is covered by tropical forests or other natural ecosystems. These provide ideal conditions for the existence of many arboviruses, which are maintained in a large variety of zoonotic cycles. The risk that new arboviruses might emerge in Brazil is related to the existence of large, densely populated cities that are infested by mosquitoes such as Culex and the highly anthropophilic Aedes aegypti. Infected humans or animals may come into these cities from ecological-epidemiological settings where arbovirus zoonoses occur. This study analyzes the risk of emergence of the alphaviruses Mayaro, Venezuelan equine encephalitis, Eastern equine encephalitis and Chikungunya; the flaviviruses yellow fever, Rocio, Saint Louis encephalitis and West Nile; and the orthobunyavirus Oropouche.

Novos registros e potencial epidemiológico de algumas espécies de mosquitos (Diptera, Culicidae), no Estado do Rio Grande do Sul

INTRODUÇÃO: A vigilância entomológica tem se mostrado uma importante estratégia de monitoramento da fauna de culicídeos com vistas a predizer o risco de exposição a espécies vetoras de patógenos. Esse trabalho apresenta uma lista de mosquitos identificados pela primeira vez no Rio Grande do Sul e discute o potencial epidemiológico de algumas espécies ocorrentes no Município de Maquiné com registros em outras regiões do Estado. MÉTODOS: Os mosquitos foram coletados com aspirador de Nasci e armadilhas CDC, entre dezembro de 2006 e dezembro de 2008, em área silvestre, rural e urbana do Município de Maquiné. RESULTADOS: Foram verificadas 55 espécies, das quais 22 são registradas pela primeira vez no estado e 10 são potencialmente vetoras do vírus Saint Louis, Oropouche, Aura, Trocara, Ilhéus, Rocio, Una, West Nile e encefalite equina do leste. CONCLUSÕES: Esses dados demonstram a importância da Vigilância Entomológica como ferramenta de informação e ação para a Vigilância em Saúde.

New report on the bionomics of Coquillettidia venezuelensis in temporary breeding sites (Diptera: Culicidae)

INTRODUCTION: Findings of immature forms of Coquillettidia venezuelensis in temporary breeding sites, without the presence of aquatic plants or other submerged plant tissue are reported. METHODS: A systematic scooping technique to collect specimens was used at the breeding site. RESULTS: Immature forms of Coquillettidia venezuelensis, Anopheles rangeli, An. evansae and Culex sp. were collected from areas of the hydroelectric power station of São Salvador, State of Goiás. CONCLUSIONS This is a novel finding relating to the bioecology of Cq. venezuelensis, a species of medical interest that has been found naturally infected with arboviruses, including Oropouche and West Nile virus.

Natural transovarial transmission of dengue virus 4 in Aedes aegypti from Cuiabá, State of Mato Grosso, Brazil

INTRODUCTION: Dengue is the most prevalent arboviral disease in tropical areas. In Mato Grosso, outbreaks are reported every year, but studies on dengue in this state are scarce. METHODS: Natural transovarial infection of Aedes aegypti by a flavivirus was investigated in the Jardim Industriário neighborhood of Cuiabá, Mato Grosso. Eggs were collected with ovitraps during the dry, intermediate, and rainy seasons of 2012. After the eggs hatched and the larvae developed to adulthood, mosquitoes (n = 758) were identified and allocated to pools of 1-10 specimens according to the collection location, sex, and climatic period. After RNA extraction, multiplex semi-nested RT-PCR was performed to detect the four dengue virus (DENV) serotypes, yellow fever virus, West Nile virus and Saint Louis encephalitis virus. RESULTS: DENV-4 was the only flavivirus detected, and it was found in 8/50 pools (16.0%). Three of the positive pools contained females, and five contained males. Their nucleotide sequences presented 96-100% similarity with DENV-4 genotype II strains from Manaus, Amazonas. The minimum infection rate was 10.5 per 1000 specimens, and the maximum likelihood estimator of the infection rate was 11.6 (95% confidence interval: 4.8; 23.3). CONCLUSIONS: This study provides the first evidence of natural transovarial infection by DENV-4 in Ae. Aegypti in Mato Grosso, suggesting that this type of infection might serve as a mechanism of virus maintenance during interepidemic periods in Cuiabá, a city where dengue epidemics are reported every year. These results emphasize the need for efficient vector population control measures to prevent arbovirus outbreaks in the state.

Design of assemblies based on polymer-coated quantum dots and organic dye

During last years, photophysical properties of complexes of semiconductor quantum dots (QDs) with organic dyes have attracted increasing interest. The development of different assemblies based on QDs and organic dyes allows to increase the range of QDs applications, which include imaging, biological sensing and electronic devices.1 Some studies demonstrate energy transfer between QDs and organic dye in assemblies.2 However, for electronic devices purposes, a polymeric matrix is required to enhance QDs photostability. Thus, in order to attach the QDs to the polymer surface it is necessary to chemically modify the polymer to induce electronic charges and stabilize the QDs in the polymer. The present work aims to investigate the design of assemblies based on polymer-coated QDs and an integrated acceptor organic dye. Polymethylmethacrylate (PMMA) and polycarbonate (PC) were used as polymeric matrices, and nile red as acceptor. Additionally, a PMMA matrix modified with 2-mercaptoethylamine is used to improve the attachment between both the donor (QDs) and the acceptor (nile red), as well as to induce a covalent bond between the modified PMMA and the QDs. An enhancement of the energy transfer efficiency by using the modified PMMA is expected and the resulting assembly can be applied for energy harvesting.

Magnetoliposomes based on manganese ferrite nanoparticles as nanocarriers for antitumor drugs

Manganese ferrite nanoparticles with a size distribution of 26 ± 7 nm (from TEM measurements) were synthesized by the coprecipitation method. The obtained nanoparticles exhibit a superparamagnetic behaviour at room temperature with a magnetic squareness of 0.016 and a coercivity field of 6.3 Oe. These nanoparticles were either entrapped in liposomes (aqueous magnetoliposomes, AMLs) or covered with a lipid bilayer, forming solid magnetoliposomes (SMLs). Both types of magnetoliposomes, exhibiting sizes below or around 150 nm, were found to be suitable for biomedical applications. Membrane fusion between magnetoliposomes (both AMLS and SMLs) and GUVs (giant unilamellar vesicles), the latter used as models of cell membranes, was confirmed by F¨orster Resonance Energy Transfer (FRET) assays, using a NBD labeled lipid as the energy donor and Nile Red or rhodamine B-DOPE as the energy acceptor. A potential antitumor thienopyridine derivative was successfully incorporated into both aqueous and solid magnetoliposomes, pointing to a promising application of these systems in oncological therapy, simultaneously as hyperthermia agents and nanocarriers for antitumor drugs.

Susceptibility of Candida biofilms to photodynamic treatment

Dissertação de mestrado em Bioengenharia

Decoloración de tintes por lacasa

Informe de investigación realizado a partir de una estancia en el Instituto de Biotecnología Medioambiental de la Universidad Tecnológica de Graz, Austria, entre Julio y Agosto de 2006. Se ha estudiado la decoloración de varios tintes sintéticos de estructuras químicas diferentes (Rojo Congo, Azul de Naftol, Indigo Carmín, Lanaset Gris, Azul de Nilo) por la enzima lacasa inmovilizada. La inmovilización de la enzima lacasa se llevó a cabo sobre esferas de alúmina (Al2O3) de 3 mm de diámetro debido a la resistecia mecánica de este material. La lacasa y la proteína inmovilizada se determinaron como la diferencia entre las concentraciones iniciales y residuales (obtenidas en los lavados). El porcentaje de lacasa inmovilizada fue del 68% y la cantidad de proteína inmovilizada por gramo de soporte de 5,6 mg. La enzima lacasa inmovilizada fue capaz de decolorar tintes de diferente estructura sin la necesidad de añadir mediadores redox, lo cual la hace una enzima muy adecuada para su aplicación en la decoloración de efluentes procedentes de la industria textil. De todas formas, son necesarios más estudios para optimizar la técnica de inmovilización así como el proceso de decoloración. Es interesante destacar que aunque hay muchos estudios basados en la oxidación de tintes textiles por lacasa la mayoría utilizan la enzima libre y hay muy poca información disponible sobre la aplicación de lacasas inmovilizadas, por lo que el presente estudio constituye una aportación muy interesante y novedosa.