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Modelling the control strategies against dengue in Singapore

BURATTINI, M. N.; CHEN, M.; CHOW, A.; COUTINHO, F. A. B.; GOH, K. T.; LOPEZ, L. F.; MA, S.; MASSAD, E.
Fonte: CAMBRIDGE UNIV PRESS Publicador: CAMBRIDGE UNIV PRESS
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
17.45%
Notified cases of dengue infections in Singapore reached historical highs in 2004 (9459 cases) and 2005 (13 817 cases) and the reason for such all increase is still to be established. We apply a mathematical model for dengue infection that takes into account the seasonal variation in incidence, characteristic of dengue fever, and which mimics the 2004-2005 epidemics in Singapore. We simulated a set of possible control strategies and confirmed the intuitive belief that killing adult mosquitoes is the most effective strategy to control an ongoing epidemic. On the other hand, the control of immature forms was very efficient ill preventing the resurgence of dengue epidemics. Since the control of immature forms allows the reduction of adulticide, it seems that the best strategy is to combine both adulticide and larvicide control measures during an outbreak, followed by the maintenance of larvicide methods after the epidemic has subsided. In addition, the model showed that the mixed strategy of adulticide and larvicide methods introduced by the government seems to be very effective in reducing the number of cases in the first weeks after the start of control.; Universidade de São Paulo - LIM01/HC-FM-USP; FAPESP; CNPq; Courage Fund

Utilização de Bacillus sphaericus Neide, 1904 para controle de Culex quinquefasciatus

Germani, Jose Carlos; Leal, Luiz Fernando Azeredo; Ruas Neto, Antonio Leite; Silveira, Sydnei Mitidieri; Minghelli, Rovena Michel
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Artigo de Revista Científica Formato: application/pdf
POR
Relevância na Pesquisa
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Observou-se neste trabalho a resposta de larvas de terceiro estádio de C. quinquefasciatus à uma formulação experimental de B. sphaericus cepa 2362. A tecnologia para obtenção do larvicida obedeceu às etapas de preparação do inoculo, fermentação envolvendo um subproduto industrial (soro de queijo), e formulação líquida com agente dispersante. Com uma mortalidade nula nos controles com água ou com placebo produzido com os agentes formulantes, observou-se como resultados em duas séries uma CL50 de 0,0007323 ± 0,0001 e CL90 de 0,0042320 ± 0,0001 ppm numa delas e CL50 de 0,0006399 ± 0,0001 e CL90 de 0,0066370 ± 0,0001 ppm na outra, considerando-se 10% de creme sedimentado utilizado nas formulações. Conclui-se que 0,01 ppm de formulações experimentais consideradas integralmente seria uma concentração eficaz num meio aquático semelhante ao testado, o que é estimulante para um incremento da produção e a continuidade dos testes com este agente de controle.; Baccilus sphaericus NEIDE, 1904 IN THE CONTROL OF Culex quinquefasciatus. The susceptibility of third-instar Culex quinquefasciatus say larvae to Bacillus sphaericus strain 2362 experimentally produced was observed. The larvicide was obtained following fermentation in cheese serum...

Eficácia e período residual do diflubenzuron para o controle de larvas de Aedes aegypti resistentes ao temefós

Machado, Angela Aparecida
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: xiii, 53 f. : il.
POR
Relevância na Pesquisa
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Pós-graduação em Agronomia (Entomologia Agrícola) - FCAV; O temefós é o larvicida mais utilizado no país, mas tem-se constatado populações resistentes a este inseticida em diversos locais, e a necessidade de substituição por outro larvicida com mecanismo de ação tóxica diferente ao temefós. O diflubenzuron (DFB), inibidor de síntese de quitina, destaca-se com grande potencial para substituir o temefós. Objetivou-se determinar a razão de resistência (RR95) de larvas de duas populações de campo (Pop. A e Pop. B) ao temefós; avaliar a eficácia do DFB para as duas populações, em condições laboratoriais; e avaliar a eficácia do DFB para as duas populações, em condições de campo, em recipientes de plástico, vidro e borracha, com a concentração de 0,25 mg/L. Em condições de laboratório, os ensaios foram realizados em sala climatizada com 26 ± 2ºC, para avaliar a razão de resistência das populações de campo ao temefós, por meio de ensaios concentração-resposta, e para avaliar a eficácia do DFB. Em condições de campo, os testes foram realizados à sombra, em abrigo coberto, com médias de tempfoitura de 22,4°C e umidade relativa do ar de 61%...

Resistance of Musca domestica L. populations to cyromazine (insect growth regulator) in Brazil

Pinto,Mara Cristina; Prado,Angelo Pires do
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2001 EN
Relevância na Pesquisa
27.45%
Five field populations of Musca domestica L. collected in poultry farms were bioassayed in order to detect possible resistance to the larvicide cyromazine in Brazil. The concentrations used were 0, 0.5, 0.1, 0.2, 0.4, 1, 2, 4 and 8 ppm. Three populations (Petrópolis, RJ, Montes Claros, MG and Promissão, SP) were resistant, while the other two populations (Ibiuna, SP and Monte Mor, SP) were more susceptible than the reference pathern used by the World Health Organization. The presence of three resistant house fly populations to cyromazine in Brazilian poultry farms strongly suggests that the operational aspects of larvicide use are important for the resistance development. Cyromazine is applied as a feed-through, both in Brazil and in the USA, where resistance has already been documented. However, in Denmark, where it was approved only as a topical manure spray, no case of resistance has yet been detected.

Development of a Bacillus sphaericus tablet formulation and its evaluation as a larvicide in the biological control of Culex quinquefasciatus

Medeiros,Flávia P Morais de; Santos,Maria Alice Varjal de Melo; Regis,Leda; Rios,Eugênia M Maranhão; Rolim Neto,Pedro J
Fonte: Instituto Oswaldo Cruz, Ministério da Saúde Publicador: Instituto Oswaldo Cruz, Ministério da Saúde
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/07/2005 EN
Relevância na Pesquisa
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This study aimed to analyze the final fermentation culture of Bacillus sphaericus 2362, standardize it and develop an active tablet formulation for use in urban mosquito breeding sites. It was performed in three phases: analysis and standardization of a B. sphaericus fermented culture; physical, chemical, and biological analysis of the active powder (solubility, residual humidity, particle size, resting angle, flowing off time, compacted density, and biological activity against Culex quinquefasciatus larvae); and the development of fast-disintegrating tablets. Five formulations with differing compositions were developed and a UV protector was added to the selected formulation. The formulation products with or without UV protector, as well as the active powder caused 100% larval mortality from 1 day to 2 months after a single treatment under simulated field conditions. These results show that the UV protector does not affect the initial larvicide activity of B. sphaericus, nor its persistence over a period of two months.

Homeopathic and larvicide effect of Eucalyptus cinerea essential oil against Aedes aegypti

Cavalca,Patrícia Aparecida Mançano; Lolis,Maria Isabel Gomes de Assumpção; Reis,Bruno; Bonato,Carlos Moacir
Fonte: Instituto de Tecnologia do Paraná - Tecpar Publicador: Instituto de Tecnologia do Paraná - Tecpar
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2010 EN
Relevância na Pesquisa
27.45%
The aim of this work to study the homeopathic and larvicide effect of Eucalyptus cinerea essential oil on Aedes aegypti. Essential oil had high larvicide effect with LC50 and LC90 of 0.38 and 0.27 mg mL-1, respectively. Generally, the homeopathy of essential oil affected the A. aegypti development stages. Dynamizations 6CH, 9CH and 12CH reduced the mean number of larvae when compared to that of control. Mean number of mosquitoes decreased through homeopathic dynamization 30CH. Results showed that E. cinerea essential oil was highly promising and could be used in public health system for the control of A. aegypti.

Comparison of the cellular fatty acid composition of a bacterium isolated from a human and alleged to be Bacillus sphaericus with that of Bacillus sphaericus isolated from a mosquito larvicide.

Siegel, J P; Smith, A R; Novak, R J
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em /03/1997 EN
Relevância na Pesquisa
27.14%
The cellular fatty acid (CFA) composition of the cytoplasmic membrane of a bacillus isolated from a human lung and deposited in the National Collection of Type Cultures as Bacillus sphaericus NCTC 11025 was determined by gas-liquid chromatography. The CFA composition of B. sphaericus 2362, isolated from a microbial larvicide, and those of B. sphaericus reference strains obtained from public collections were also determined. Samples were grouped by hierarchical cluster analysis based on the unpaired-group method using arithmetic averages. Samples that linked at a Euclidean distance of < or = 2.0 U were considered to belong to the same strain. NCTC 11025 and the type strain of B. sphaericus, ATCC 14577, were mixed; all other isolates were monotypic. The predominant fatty acid in NCTC 11025 was 12-methyltetradecanoic acid, while the predominant fatty acid in the remaining isolates was 13-methyltetradecanoic acid. NCTC 11025 linked to the other isolates at a Euclidean distance of 83.8 U, and we concluded that it belongs to a different species that we could not identify. We could distinguish among six DNA homology groups of B. sphaericus by using fatty acids. Within DNA homology group IIA, strain 2362 could be distinguished from other strains belonging to serotype H5a...

The value of a spreading agent in larvicidal formulations containing DDT

Msangi, A. S.
Fonte: PubMed Publicador: PubMed
Tipo: Artigo de Revista Científica
Publicado em //1959 EN
Relevância na Pesquisa
17.45%
The value of a spreading agent in a 5% solution of DDT in oil was assessed under semifield conditions using third-stage laboratory-bred larvae of Anopheles gambiae. These larvae were treated with known dosages of the larvicide with and without the addition of spreading agent, and the mortalities produced by the two forms of the larvicide were compared. An attempt was also made to compare the efficacy of the two forms under field conditions. The trials described seem to have shown quite conclusively that, so far as a 5% solution of DDT in oil is concerned, there is no advantage to be gained by adding spreading agents to the larvicide.

Modelling the control strategies against dengue in Singapore

BURATTINI, M. N.; CHEN, M.; CHOW, A.; COUTINHO, F. A. B.; GOH, K. T.; LOPEZ, L. F.; MA, S.; MASSAD, E.
Fonte: Cambridge University Press Publicador: Cambridge University Press
Tipo: Artigo de Revista Científica
EN
Relevância na Pesquisa
17.45%
Notified cases of dengue infections in Singapore reached historical highs in 2004 (9459 cases) and 2005 (13 817 cases) and the reason for such an increase is still to be established. We apply a mathematical model for dengue infection that takes into account the seasonal variation in incidence, characteristic of dengue fever, and which mimics the 2004–2005 epidemics in Singapore. We simulated a set of possible control strategies and confirmed the intuitive belief that killing adult mosquitoes is the most effective strategy to control an ongoing epidemic. On the other hand, the control of immature forms was very efficient in preventing the resurgence of dengue epidemics. Since the control of immature forms allows the reduction of adulticide, it seems that the best strategy is to combine both adulticide and larvicide control measures during an outbreak, followed by the maintenance of larvicide methods after the epidemic has subsided. In addition, the model showed that the mixed strategy of adulticide and larvicide methods introduced by the government seems to be very effective in reducing the number of cases in the first weeks after the start of control.

Identification of Larvicide-Resistant Catch Basins from Three Years of Larvicide Trials in a Suburb of Chicago, IL

Harbison, Justin E; Sinacore, James M; Henry, Marlon; Xamplas, Christopher; Dugas, Lara R; Ruiz, Marilyn O’Hara
Fonte: Libertas Academica Publicador: Libertas Academica
Tipo: Artigo de Revista Científica
Publicado em 13/10/2014 EN
Relevância na Pesquisa
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The tens of thousands of catch basins found in many urban areas are a primary target of local vector control agencies for seasonal application of extended-release larvicides. A concern with using larvicides in these structures is that active ingredients can be hampered by high flows, debris, and sediment, all of which are common to these structures. As such a certain proportion of basins may be “resistant” to larvicide treatments due to site specific characteristics that may promote these and other factors that hinder larvicide action and/or promote mosquito infestation. Analyses from three years of larvicide efficacy trials suggest that over a quarter of basins in the study area may not be receiving adequate protection from a single dose of larvicide that is routinely applied. Implications of increasing the dose and/or toxicity of larvicide treatments are discussed further.

Observed Loss and Ineffectiveness of Mosquito Larvicides Applied to Catch Basins in the Northern Suburbs of Chicago IL, 2014

Harbison, Justin E; Layden, Jennifer E; Xamplas, Christopher; Zazra, Dave; Henry, Marlon; Ruiz, Marilyn O’Hara
Fonte: Libertas Academica Publicador: Libertas Academica
Tipo: Artigo de Revista Científica
Publicado em 21/04/2015 EN
Relevância na Pesquisa
17.45%
In the northeastern part of the greater Chicago metropolitan area, the North Shore Mosquito Abatement District (NSMAD) treats approximately 50,000 catch basins each season with larvicide tablets as part of its effort to reduce local populations of the West Nile virus (WNV) vector Culex pipiens. During the 2014 season, an NSMAD technician monitored a subset of 60–195 basins weekly for 18 weeks among the communities of the District for the presence of mosquitoes. Monitoring found no clear evidence in the reduction of mosquitoes with the use of larvicides, and visual inspections of 211 larvicide-treated basins found that the majority (162, 76.8%) were missing tablets 1–17 weeks after applications. This loss of treatment may be due to the rapid dissolution or flushing of larvicides and would help explain why the larvicide appeared to be ineffective.

ANTHELMINTIC ACTIVITY OF LAPACHOL, β-LAPACHONE AND ITS DERIVATIVES AGAINST Toxocara canis LARVAE

MATA-SANTOS, Taís; PINTO, Nitza França; MATA-SANTOS, Hilton Antônio; DE MOURA, Kelly Gallan; CARNEIRO, Paula Fernandes; CARVALHO, Tatiane dos Santos; DEL RIO, Karina Pena; PINTO, Maria do Carmo Freire Ribeiro; MARTINS, Lourdes Rodrigues; FENALTI, Julia
Fonte: Revista do Instituto de Medicina Tropical de São Paulo Publicador: Revista do Instituto de Medicina Tropical de São Paulo
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
17.63%
Anthelmintics used for intestinal helminthiasis treatment are generally effective; however, their effectiveness in tissue parasitosis (i.e. visceral toxocariasis) is moderate. The aim of this study was to evaluate the in vitroactivity of lapachol, β-lapachone and phenazines in relation to the viability of Toxocara canis larvae. A concentration of 2 mg/mL (in duplicate) of the compounds was tested using microculture plates containing Toxocara canis larvae in an RPMI-1640 environment, incubated at 37 °C in 5% CO2 tension for 48 hours. In the 2 mg/mL concentration, four phenazines, lapachol and three of its derivatives presented a larvicide/larvistatic activity of 100%. Then, the minimum larvicide/larvistatic concentration (MLC) test was conducted. The compounds that presented the best results were nor-lapachol (MLC, 1 mg/mL), lapachol (MLC 0.5 mg/mL), β-lapachone, and β-C-allyl-lawsone (MLC, 0.25 mg/mL). The larvae exposed to the compounds, at best MLC with 100% in vitro activity larvicide, were inoculated into healthy BALB/c mice and were not capable of causing infection, confirming the larvicide potential in vitro of these compounds.

Estudo químico biomonitorado por ensaio com larvas Aedes aegypti das espécies Ocotea velloziana (Meisn.) Mez. e Aiouea trinervis (Meisn.)

Silva, Lilliam May Grespan Estodutto da
Fonte: Universidade Federal de Mato Grosso do Sul Publicador: Universidade Federal de Mato Grosso do Sul
Tipo: Dissertação de Mestrado
POR
Relevância na Pesquisa
17.45%
O estudo químico biomonitorado dos componentes de plantas tem sido adotado como ferramenta para obtenção de princípios ativos. O emprego de produtos naturais para controle de pragas e tratamento de doenças não é recente, sendo utilizado antes do advento dos produtos sintéticos. A biodiversidade do Cerrado e Pantanal é pouco conhecida e muitas espécies são endêmicas desses biomas. O presente estudo químico biomonitorado relata os resultados do teste biológico para a verificação da atividade larvicida frente à larva do mosquito Aedes aegypti (Linneus 1762) dos extratos etanólicos da casca do caule de Ocotea velloziana (Meisn.) Mez. e dos frutos de Aiouea trinervis (Meisn.). O estudo fitoquímico consistiu no isolamento, na identificação e elucidação estrutural dos metabólitos secundários responsáveis pela bio-atividade apresentada pelos extratos. Os extratos etanólicos das duas espécies selecionadas através do ensaio biológico larvicida foram submetidos a técnicas cromatográficas de separação incluindo cromatografia em coluna de sílica gel, sílica gel 60 RP-18, de Sephadex LH-20 e cromatografia líquida de alta eficiência em fase reversa. As determinações estruturais foram efetuadas com base nos dados espectroscópicos de RMN de ¹H...

Experimental comparison of aerial larvicides and habitat modification for controlling disease-carrying Aedes vigilax mosquitoes

de Little, S.; Williamson, G.; Bowman, D.; Whelan, P.; Brook, B.; Bradshaw, C.
Fonte: John Wiley & Sons Ltd Publicador: John Wiley & Sons Ltd
Tipo: Artigo de Revista Científica
Publicado em //2012 EN
Relevância na Pesquisa
27.45%
BACKGROUND: Microbial and insect-growth-regulator larvicides dominate current vector control programmes because they reduce larval abundance and are relatively environmentally benign. However, their short persistence makes them expensive, and environmental manipulation of larval habitat might be an alternative control measure. Aedes vigilax is a major vector species in northern Australia. A field experiment was implemented in Darwin, Australia, to test the hypotheses that (1) aerial microbial larvicide application effectively decreases Ae. vigilax larval presence, and therefore adult emergence, and (2) environmental manipulation is an effective alternative control measure. Generalised linear and mixed-effects modelling and information-theoretic comparisons were used to test these hypotheses. RESULTS: It is shown that the current aerial larvicide application campaign is effective at suppressing the emergence of Ae. vigilax, whereas vegetation removal is not as effective in this context. In addition, the results indicate that current larval sampling procedures are inadequate for quantifying larval abundance or adult emergence. CONCLUSIONS: This field-based comparison has shown that the existing larviciding campaign is more effective than a simple environmental management strategy for mosquito control. It has also identified an important knowledge gap in the use of larval sampling to evaluate the effectiveness of vector control strategies.; Siobhan C de Little...

Evaluating the toxicity of oil of lemon eucalyptus, Corymbia citriodora (Hook.), against larvae of the Asian tiger mosquito and non-target fish and larval amphibians; Evaluación de la toxicidad del aceite del eucalipto limón, Corymbia citriodora (Hook.), contra las larvas de mosquito tigre y peces y anfibios no objetivo

Escartin, Santi; Mariani, Simone
Fonte: Murcia: Servicio de Publicaciones de la Universidad de Murcia Publicador: Murcia: Servicio de Publicaciones de la Universidad de Murcia
Tipo: Artigo de Revista Científica Formato: application/pdf
ENG
Relevância na Pesquisa
27.14%
Hemos probado la toxicidad del aceite del eucalipto limón (OLE) contra las larvas de mosquito tigre Aedes (Stegomya) albopictus (Skuse, 1895) (Diptera: Culicidae) y contra vertebrados acuáticos no objetivo, el pez Gambusia affinis (Baird and Girard, 1853) y el renacuajo de la rana Pelophylax perezi (López-Seodane, 1885). La mezcla acuosa de OLE fue efectiva como larvicida y letal para gambúsias y renacuajos. La mezcla acuosa expuesta durante una semana al aire libre no tuvo efectos sobre las larvas. El OLE puro aplicado sobre la superficie del agua matólas larvas a muy bajas concentraciones y sin tener en cuenta el volumen del agua. El OLE ha mostrado ser un compuesto útil contra las larvas de mosquito tigre especialmente en los lugares de cría aislados de los ecosistemas nativos.; ABSTRACT: We evaluated the toxicity of oil of lemon eucalyptus (OLE) against larvae of the tiger mosquito Aedes (Stegomya) albopictus (Skuse, 1895) (Diptera: Culicidae) and non-target aquatic vertebrates, the fish Gambusia affinis (Baird and Girard, 1853) and the tapole of the frog Pelophylax perezi (López-Seodane, 1885). The water-mixture of OLE was effective as a larvicide and lethal to both mosquitofish and tadpoles in the short-term. The water-mixture left in the open air over a week had no effect on larvae. Pure OLE released on the water surface killed larvae at very low concentrations irrespectively of the volume of water medium. OLE seems a useful compound to be used against tiger mosquito larvae especially in mosquito breeding sites isolated from native ecosystems.

ANTHELMINTIC ACTIVITY OF LAPACHOL, β-LAPACHONE AND ITS DERIVATIVES AGAINST Toxocara canis LARVAE

MATA-SANTOS,Taís; PINTO,Nitza França; MATA-SANTOS,Hilton Antônio; DE MOURA,Kelly Gallan; CARNEIRO,Paula Fernandes; CARVALHO,Tatiane dos Santos; DEL RIO,Karina Pena; PINTO,Maria do Carmo Freire Ribeiro; MARTINS,Lourdes Rodrigues; FENALTI,Juliana Montell
Fonte: Instituto de Medicina Tropical Publicador: Instituto de Medicina Tropical
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
17.63%
Anthelmintics used for intestinal helminthiasis treatment are generally effective; however, their effectiveness in tissue parasitosis (i.e. visceral toxocariasis) is moderate. The aim of this study was to evaluate the in vitroactivity of lapachol, β-lapachone and phenazines in relation to the viability of Toxocara canis larvae. A concentration of 2 mg/mL (in duplicate) of the compounds was tested using microculture plates containing Toxocara canis larvae in an RPMI-1640 environment, incubated at 37 °C in 5% CO2 tension for 48 hours. In the 2 mg/mL concentration, four phenazines, lapachol and three of its derivatives presented a larvicide/larvistatic activity of 100%. Then, the minimum larvicide/larvistatic concentration (MLC) test was conducted. The compounds that presented the best results were nor-lapachol (MLC, 1 mg/mL), lapachol (MLC 0.5 mg/mL), β-lapachone, and β-C-allyl-lawsone (MLC, 0.25 mg/mL). The larvae exposed to the compounds, at best MLC with 100% in vitro activity larvicide, were inoculated into healthy BALB/c mice and were not capable of causing infection, confirming the larvicide potential in vitro of these compounds.

Evaluation of the toxicity and molluscicidal and larvicidal activities of Schinopsis brasiliensis stem bark extract and its fractions

Santos,Clisiane C.S.; Araújo,Silvan S.; Santos,André L.L.M.; Almeida,Elis C.V.; Dias,Antônio S.; Damascena,Nicole P.; Santos,Deisylaine M.; Santos,Matheus I.S.; A.L.R. Júnior,Karlos; Pereira,Carla K.B.; Lima,Amanda C.B.; Shan,Andrea Y.K.V.; Sant'ana,A
Fonte: Sociedade Brasileira de Farmacognosia Publicador: Sociedade Brasileira de Farmacognosia
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
27.14%
Dengue fever and schistosomiasis are major public health issues for which vector control using larvicide and molluscicide substances present in plants provides a promising strategy. This study evaluated the potential toxicity of the extract of hydroethanol Schinopsis brasiliensis Engl., Anacardiaceae, stem bark and its chloroform, hexane, ethyl acetate, and hydromethanol fractions against Artemia salina and Aedes Aegypti larvae and snails Biomphalaria glabrata. All of the assays were performed in triplicate and the mean mortality rates were used to determine the LC50 and LC90 values using the probit method. The hydroethanol hydromethanol extract and fraction were free of toxicity towards A. salina (LC50 > 1000 µg/ml), while chloroform fraction was moderately toxic (LC50 313 µg/ml); ethyl acetate and hexane fractions displayed low toxicity, with LC50 557 and 582 µg/ml, respectively. Chloroform, hexane, and ethyl acetate fractions showed larvicidal potential towards A. aegypti (LC50 values of 345, 527 and 583 µg/ml, respectively), while chloroform and ethyl acetate fractions were highly toxic to B. glabrata (LC90 values of 68 and 73 µg/ml, respectively). Based on these findings, ethyl acetate, chloroform, and hexane fractions should be further investigated for their potential use against the vectors of dengue and schistosomiasis.

ANTHELMINTIC ACTIVITY OF LAPACHOL, β-LAPACHONE AND ITS DERIVATIVES AGAINST Toxocara canis LARVAE; Atividade anti-helmíntica do lapachol, β-lapachona e derivados contra larvas de Toxocara canis

MATA-SANTOS, Taís; PINTO, Nitza França; MATA-SANTOS, Hilton Antônio; DE MOURA, Kelly Gallan; CARNEIRO, Paula Fernandes; CARVALHO, Tatiane dos Santos; DEL RIO, Karina Pena; PINTO, Maria do Carmo Freire Ribeiro; MARTINS, Lourdes Rodrigues; FENALTI, Julia
Fonte: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo Publicador: Universidade de São Paulo. Instituto de Medicina Tropical de São Paulo
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/06/2015 ENG
Relevância na Pesquisa
17.63%
Os anti-helmínticos empregados no tratamento das helmintoses intestinais, de modo geral, são eficazes, porém nas parasitoses teciduais, como é o caso da toxocaríase visceral, a eficácia é moderada. Este estudo teve como objetivo avaliar in vitro a atividade do lapachol, β-lapachona e fenazinas derivadas da β-lapachona sobre a viabilidade de larvas de Toxocara canis. Os compostos foram testados na concentração de 2 mg/mL (em duplicata) em placas de microcultivo, contendo larvas de T. canis em meio RPMI-1640, sendo incubados, a 37 °C, em tensão de CO2 de 5%, por 48 horas. Na concentração de 2 mg/mL, quatro fenazinas, o lapachol e três derivados, apresentaram atividade larvicida/larvostática de 100%. A seguir, foi realizado o teste de concentração larvicida/larvostártica mínima (CLM). Os compostos que apresentaram os melhores resultados foram o nor-lapachol (CLM, 1 mg/mL), lapachol (CLM, 0,5 mg/mL), a β-lapachona e a β-C-alil-lausona (CLM, 0,25 mg/mL). As larvas expostas aos compostos, na melhor CLM 100% in vitro foram inoculadas em camundongos BALB/c saudáveis não sendo capazes de causar infecção, confirmando o potencial larvicida in vitro desses compostos.; Anthelmintics used for intestinal helminthiasis treatment are generally effective; however...

Evaluation of larvicides in developing management guidelines for long-term control of pest blackflies (Diptera: Simuliidae) along the Orange River, South Africa

Palmer,R.W.; Rivers-Moore,N.A.
Fonte: Onderstepoort Journal of Veterinary Research Publicador: Onderstepoort Journal of Veterinary Research
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2008 EN
Relevância na Pesquisa
27.14%
In 2000 and 2001 Orange River levels were higher than normal: associated serious outbreaks of blackfly had a substantial detrimental impact on the local economy. The poor control was attributed to the suspected development of larval resistance to temephos. A long-term solution to blackfly control, through the identification of a suitable replacement to temephos for use during high flow conditions, was proposed. This study, however, failed to identify or register a suitable larvicide for use during high flow conditions. Although permethrin was highly effective against blackfly larvae, it was rejected because of its detrimental impacts on non-target fauna. Various formulations of locally produced dry Bacillus thuringiensis var. israelensis (B.t.i.) were tested, but these were ineffective against blackflies. The study also confirmed that resistance to temephos has developed among Simulium chutteri in the middle and lower Orange River. The feasibility of "reversing" the resistance to temephos through the use of the synergist piperonyl butoxide (PEO) was investigated, but the results were not favourable. Furthermore, PBO was highly toxic to blackflies and non-target organisms, and was not recommended for further testing. This means that B.t.i. currently remains the only symptomatic measure of treatment currently applied. Although resistance to B.t.i. has not been reported for blackflies elsewhere in South Africa...

Optimisation of Bacillus thuringiensis var. israelensis (Vectobac®) applications for the blackfly control programme on the Orange River, South Africa

Rivers-Moore,NA; Bangay,S; Palmer,RW
Fonte: Water SA Publicador: Water SA
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2008 EN
Relevância na Pesquisa
17.76%
The Orange River, South Africa's largest river, is a critical water resource for the country. In spite of the clear economic benefits of regulating river flows through a series of impoundments, one of the significant undesirable ecological consequences of this regulation has been the regular outbreaks of the pest blackfly species Simulium chutteri and S. damnosum s.l. (Diptera: Simuliidae). The current control programme, carried out by the South African National Department of Agriculture, uses regular applications, by helicopter, of the target-specific bacterial larvicide Bacillus thuringiensis var. israelensis. While cost-benefit analyses show significant benefits to the control programme, benefits could potentially be further increased through applying smaller volumes of larvicide in an optimised manner, which incorporates upstream residual amounts of pesticide through downstream carry. Using an optimisation technique applied in the West African Onchocerciasis Control Programme, to a 136 km stretch of the Orange River which includes 31 blackfly breeding sites, we demonstrate that 28.5% less larvicide could be used to potentially achieve the same control of blackfly. This translates into potential annual savings of between R540 000 and R1 800 000. A comparison of larvicide volumes estimated using traditional vs. optimised approaches at different discharges...