Virtual reality and augmented reality as strategies for teaching social skills to individuals with intellectual disability: A systematic review.

Virtual reality (VR) and augmented reality (AR) programs have proliferated significantly in recent years and they are finding their way into different educational and therapeutic purposes. This systematic review aims at analyzing the virtual reality and augmented reality programs designed to promote the development of social skills in individuals with intellectual disability. Searches were carried out in the Scopus, Science Direct, Springer and Web of Science databases in the period from 2005 to 2020. A total of six articles met the inclusion criteria. A descriptive data analysis was performed. The results show that the clinical profile of the individuals who participated in the interventions is diverse. It can be concluded that there is some scientific evidence that points to the usefulness of VR and AR in the development of intervention programs to improve the social skills of individuals diagnosed with developmental deficits. However, it is necessary to acknowledge methodological limitations such as the lack of control groups, follow-up measures and of generalization of the results.

Efectos del entrenamiento en marcos relacionales de condicionalidad sobre el responder relacional deíctico / Effects of Training in Conditional Relational Framing on the Deictic Relational Responding

Resumen Desde la Teoría de los Marcos Relacionales, la toma de perspectiva se concibe como un patrón de responder relacional arbitrariamente aplicable bajo control de claves contextuales deícticas personales, espaciales y temporales. Además, se asume necesaria la capacidad para responder relacionalmente bajo el control de claves contextuales condicionales. Sin embargo, no se ha reportado evidencia empírica que permita identificar la relación existente entre los marcos de condicionalidad y la precisión en el responder relacional deíctico. El objetivo del estudio fue analizar si el entrenamiento en marco de condicionalidad podría facilitar el desempeño sobre el responder deíctico. Participaron cuatro niños con desarrollo normalizado que fueron divididos en dos condiciones experimentales (C1 y C2). Los participantes de ambas condiciones se expusieron a un protocolo de evaluación y entrenamiento en marcos deícticos. A su vez, solo los participantes de la C2 se expusieron a una fase de evaluación y entrenamiento en marcos de condicionalidad previo al entrenamiento en marcos deícticos. Los resultados mostraron que todos los participantes exhibieron mejoras en sus ejecuciones post-test en las relaciones deícticas y que los participantes de C2 obtuvieron mejores resultados con respecto a su pre-test en los niveles de mayor complejidad deíctica tras el entrenamiento en marcos condicionales. Se discute la necesidad de protocolos de toma de perspectiva más naturalistas que posibiliten indagar en cómo se desarrollan los términos relacionales y se abstrae la función de las claves contextuales que permiten interpretar, atribuir y predecir el comportamiento de otro.

Abstract According to Relational Frame Theory, perspective taking is conceived as an arbitrarily applicable relational pattern of relational responding under the control of personal, spatial, and temporal deictic contextual cues. Furthermore, the ability to respond relationally under the control of conditional contextual cues is assumed to be necessary. However, no empirical evidence has been reported to identify the relationship between conditionality frames and accuracy in deictic relational responding. The study aimed to analyze whether training in conditionality frames could facilitate performance on deictic responding. Four children with normalized development participated and were divided into two experimental conditions (C1 and C2). Participants in both conditions were exposed to an evaluation protocol and training on deictic frames. In turn, only C2 participants were exposed to an evaluation and training phase in conditionality frames before the training in deictic frames. Results showed that all the participants exhibited improvements in their post-test performances on deictic relations and that the C2 participants performed better with respect to their pre-test on the levels of greater deictic complexity after training in conditional frames. We discuss the need for more naturalistic perspective-taking protocols that allow us to investigate how relational terms are developed and abstract the role of contextual cues that allow us to interpret, attribute, and predict another's behavior.

Reversal of Resistance to the Larvicide Temephos in an Aedes aegypti (Diptera: Culicidae) Laboratory Strain From Cuba.

The objective of this investigation was to know whether the organophosphate temephos resistance developed in larvae from a laboratory strain of Aedes aegypti (Linnaeus, 1762) from Cuba could be reversed. The resistant laboratory strain of Ae. aegypti, named SAN-F6, was left without temephos selection pressure for 12 generations. The level of temephos resistance was determined using WHO bioassays and mechanisms of metabolic resistance were determined based on enzyme activity levels detected by biochemical assays. Bioassays and biochemical assays were conducted on the SAN-F6 parental strain and every three reversal generations (SANRevF3, SANRevF6, SANRevF9, and SANRevF12) without temephos selection pressure. After 19 yr of keeping the SAN-F6 strain under selection pressure with the LC90 of temephos, the resistance ratio (RR50) was 47.5×. Biochemical assays indicated that esterase and glutathione S-transferase are still responsible for temephos resistance in this strain, but not mixed-function oxidase. Experiments on resistance reversal showed that temephos susceptibility could be recovered as α esterase activity levels decreased. The SAN-F6 strain has provided an essential basis for studies of temephos resistance in Cuba. It was demonstrated that the resistance developed to the larvicide temephos in Ae. aegypti from this Cuban lab strain is a reversible phenomenon, which suggests that similar outcomes might be expected in field populations. As such, the use of temephos alternated with other larvicides recommended by WHO such as Bti or pyriproxyfen is recommended to maintain the effectiveness of temephos and to achieve more effective control of Ae. aegypti.

Evaluación de la resistencia a insecticidas de una cepa de Aedes aegypti de El Salvador / Assessing the insecticide resistance of an Aedes aegypti strain in El Salvador

OBJETIVOS: Evaluar el nivel de susceptibilidad a insecticidas de una cepa de Aedes aegypti procedente de El Salvador y describir los posibles mecanismos de resistencia al temefós. MÉTODOS: Se evaluó una cepa de A. aegypti procedente del municipio de Soyapango, departamento de San Salvador, El Salvador. Mediante bioensayos se determinó la susceptibilidad de las larvas al insecticida organofosforado temefós y a tres piretroides (deltametrina, lambdacialotrina y cipermetrina) y de los adultos a un insecticida organofosforado (clorpirifós). Se determinó el factor de resistencia (FR50) con respecto a una cepa sensible de referencia (Rockefeller). Se estableció el mecanismo de resistencia al temefós mediante el empleo de sustancias sinergistas, ensayos bioquímicos de actividad enzimática y zimogramas en gel de poliacrilamida. RESULTADOS: Las larvas de la cepa estudiada mostraron una alta resistencia al temefós (FR50 = 24,16). De las enzimas analizadas, se encontró que solo la esterasa A4 estaba vinculada al mecanismo de resistencia al temefós. Los mosquitos adultos resultaron susceptibles a la lambdacialotrina y al clorpirifós y su resistencia a la deltametrina y la cipermetrina quedó en la categoría de verificación. CONCLUSIONES: La resistencia al temefós podría reducir la eficacia del control químico del mosquito A. aegypti en la zona estudiada de El Salvador. Los insecticidas clorpirifós, lambdacialotrina y cipermetrina son buenos candidatos alternativos a utilizar en las nuevas intervenciones de control de este vector.

OBJECTIVES: To assess the level of insecticide susceptibility of a certain Aedes aegypti strain found in El Salvador and to explain the mechanisms for its resistance to temephos. METHODS: An A. aegypti strain from the municipality of Soyapango, Department of San Salvador, El Salvador, was studied. Bioassays were used to determine the susceptibility of the larvae to the organophosphate insecticide temephos and to three pyrethroids (deltamethrin, lambda-cyhalothrin, and cypermethrin); and of adults to an organophosphate insecticide (chlorpyrifos). The resistance factor (RF50) with determined with respect to a reference susceptible strain (Rockefeller). The mechanism of temephos resistance was determined through the use of synergistic substances, biochemical assays for enzymatic activity, and polyacrylamide gel zymograms. RESULTS: The larvae of the strain studied proved highly resistant to temephos (RF50 = 24.16). Of the enzyme samples analyzed, only the esterase A4 was linked to the mechanism of temephos resistance. The adult mosquitoes were susceptible to lambda-cyhalothrin and chlorpyrifos; and resistance to deltamethrin and cypermethrin fell into the category needing further verification. CONCLUSIONS: Temephos resistance could reduce the efficiency of chemical control of the A. aegypti mosquito in El Salvador study area. Chlorpyrifos, lambda-cyhalothrin, and cypermethrin are good alternative insecticides for use in new efforts to control this vector.

[Assessing the insecticide resistance of an Aedes aegypti strain in El Salvador]. / Evaluación de la resistencia a insecticidas de una cepa de Aedes aegypti de El Salvador.

OBJECTIVES: To assess the level of insecticide susceptibility of a certain Aedes aegypti strain found in El Salvador and to explain the mechanisms for its resistance to temephos. METHODS: An A. aegypti strain from the municipality of Soyapango, Department of San Salvador, El Salvador, was studied. Bioassays were used to determine the susceptibility of the larvae to the organophosphate insecticide temephos and to three pyrethroids (deltamethrin, lambda-cyhalothrin, and cypermethrin); and of adults to an organophosphate insecticide (chlorpyrifos). The resistance factor (RF50) with determined with respect to a reference susceptible strain (Rockefeller). The mechanism of temephos resistance was determined through the use of synergistic substances, biochemical assays for enzymatic activity, and polyacrylamide gel zymograms. RESULTS: The larvae of the strain studied proved highly resistant to temephos (RF50 = 24.16). Of the enzyme samples analyzed, only the esterase A4 was linked to the mechanism of temephos resistance. The adult mosquitoes were susceptible to lambda-cyhalothrin and chlorpyrifos; and resistance to deltamethrin and cypermethrin fell into the category needing further verification. CONCLUSIONS: Temephos resistance could reduce the efficiency of chemical control of the A. aegypti mosquito in El Salvador study area. Chlorpyrifos, lambda-cyhalothrin, and cypermethrin are good alternative insecticides for use in new efforts to control this vector.

Determinación in vivo del papel de las enzimas esterasas y glutation transferasa en la resistencia a piretroides en Aedes aegypti (Diptera: Culicidae) / Determination in vivo of the role of esterase and gluthation transferase enzymes in pyrethroid resistance of Aedes aegypti (Diptera: Cullicidae)

Se realizó un estudio in vivo a través del uso de 2 sinergistas, el trifenil fosfato (TFF) inhibidor específico de esterasas y el ácido etacrínico (AE), inhibidor específico de la enzima glutation transferasa (GST), para determinar si estas enzimas eran responsables de la resistencia a piretroides en Aedes aegypti. Para el trabajo se utilizaron 2 cepas de Aedes aegypti resistentes a insecticidas, una cepa que fue seleccionada con temefos por 6 generaciones de selección (SAN-F6) y otra con deltametrina por 12 generaciones de selección con este insecticida (SAN-F12), ambas resultaron ser resistentes a insecticidas piretroides. Se demostró a través del uso de los sinergistas TFF y AE que las enzimas esterasas y GST son responsables de la resistencia a los piretroides en estas cepas. Esos resultados demuestran la existencia de un fenómeno de resistencia cruzada y multirresistencia, lo cual debe tenerse en cuenta en las estrategias de uso de insecticidas para el control de este vector.

An in vivo study of two synergists, that is, Triphenil phosphate -specific esterase inhibitor- and ethacrynic acid specific gluthation transferase inhibitor- was performed to determine if these enzymes were responsible for pyrethroid resistance of Aedes aegypti. To this end, two insecticide resistant Aedes aegypti strains were used, one strain selected with temephos by six selection generations (SAN-F6) and the other strain with delmamethrin by 12 selection generations (SAN-F12), being both strains resistant to pyrethroid insecticices. Through the use of TPP and EA synergists, it was proved that esterase and gluthation-s-transferase (GST) enzymes were responsible for pryrethroid resistance of these strains. These results showed the existence of cross-resistance and multidrug resistance, which should be taken into account for insecticide use strategies aimed at vector control.

Levels of insecticide resistance and resistance mechanisms in Aedes aegypti from some Latin American countries.

Eight Latin American strains of Aedes aegypti were evaluated for resistance to 6 organophosphates (temephos, malathion, fenthion, pirimiphos-methyl, fenitrothion, and chlorpirifos) and 4 pyrethroids (deltamethrin, lambdacyhalothrin, betacypermethrin, and cyfluthrin) under laboratory conditions. In larval bioassays, temephos resistance was high (resistance ratio [RR50], > or =10X) in the majority of the strains, except for the Nicaragua and Venezuela strains, which showed moderate resistance (RR50, between 5 and 10X). The majority of the strains were susceptible to malathion, fenthion, and fenitrothion. However, resistance to pirimiphos-methyl ranged from moderate to high in most of the strains. Larvae from Havana City were resistant to 3 of the pyrethroids tested and moderately resistant to cyfluthrin. The Santiago de Cuba strain showed high resistance to deltamethrin and moderate resistance to the other pyrethroids (lambdacyhalothrin, betacypermethrin, and cyfluthrin). The rest of the strains were susceptible to pyrethroids, except for the Jamaica and Costa Rica strains, which showed moderate resistance to cyfluthrin, and Peru and Venezuela, which showed resistance to deltamethrin. Adult bioassays showed that all the strains were resistant to dichlorodiphenyl-trichloroethane and to the majority of pyrethroids evaluated. The use of the synergists S,S,S,-tributyl phosphorotrithioate and piperonil butoxide showed that esterase and monooxygenases played an important role in the temephos, pirimiphos-methyl, and chlorpirifos resistance in some strains. Biochemical tests showed high frequencies of esterase and glutathione-S-transferase activity; however, the frequency of altered acetylcholinesterase mechanism was low. The polyacrylamide electrophoresis gel detected the presence of a strong band called Est-A4. Insecticide resistance in Ae. aegypti is a serious problem facing control operations, and integrated control strategies are recommended to help prevent or delay the temephos resistance in larvae and pyrethroids resistance in adults.

Selection of insensitive acetylcholinesterase as a resistance mechanism in Aedes aegypti (Diptera: Culicidae) from Santiago de Cuba.

A sample of Aedes aegypti (L.) (Diptera: Culicidae) from Santiago de Cuba, Cuba, with a high level of propoxur resistance compared with the reference susceptible Rockefeller strain (12.60 x at the 50% lethal concentration [LC50] and 18.08 at the 90% lethal concentration [LC90]), with a 4.3% frequency of insensitive acetylcholinesterase (AChE) frequency, was subjected to propoxur selection for 13 successive generations to increase the frequency of this resistance mechanism in Ae. aegypti. High resistance to propoxur was developed during this selection (41.73-fold), and the frequency of insensitive AChE mechanism was increased 13.25-fold. Other mechanisms (overproduced esterases, glutathione transferases, or monooxygenases) were not detected in the propoxur-selected strain. The selection of an insensitive AChE resistance mechanism in Ae. aegypti has important implications and will be a valuable resource for genetic studies and molecular characterization of the ace gene mutation(s) associated with insecticide resistance in Ae. aegypti.

Pyrethroid insecticide-resistant strain of Aedes aegypti from Cuba induced by deltamethrin selection.

A sample of Aedes aegypti L. from Santiago de Cuba with a high level of deltamethrin resistance (113.7 x at the 50% lethal concentration [LC50]), was subjected to deltamethrin selection to determine the capacity of this population to evolve higher resistance under intensive laboratory selection pressure, to characterize that resistance, to attempt to identify some of the mechanisms involved, and to use it as a reference strain for future molecular research. High resistance developed after 12 generations of selection (1,425 x). After selection for 12 generations with deltamethrin, the Santiago de Cuba colony (SAN-F12) showed little or no cross-resistance to the organophosphates evaluated, but high cross-resistance was observed for all the pyrethroids in larvae from this strain: lambdacyhalothrin (197.5 x), cypermethrin (45 x), and cyfluthrin (41.2 x). Adult bioassays reveal that a SAN-F12 strain was resistant to the pyrethroid and the organochlorine dichlorodiphenyltrichloroethane (DDT). Synergism tests implicated detoxifying esterase or glutathione S-transferase (GST) and monooxygenase in pyrethroid resistance. Biochemical tests reveal that acetylcholinesterase was not involved in deltamethrin resistance. The frequency of GST enzyme increased from 0.43 in Santiago de Cuba to 0.88 in SAN-F12. Esterase frequency increased from 0.12 in Santiago de Cuba to 0.63 in SAN-F6 and it diminished to 0.38 in SAN-F12. The polyacrylamide gel electrophoresis and inhibition study suggests the presence of elevated esterase activity not associated with pyrethroid resistance. The presence of both DDT and pyrethroid resistance in the SAN-F12 strain suggests the presence of a knockdown (Kdr)-type resistance mechanism, although the frequency of this mechanism was low. Resistance to deltamethrin could be associated with esterase or GST mechanisms, and more investigation is required. This information contributes to the improvement of resistance management strategies in the Cuban Ae. aegypti control program.

Cross-resistance to pyrethroid and organophosphorus insecticides induced by selection with temephos in Aedes aegypti (Diptera: Culicidae) from Cuba.

A sample of Aedes aegypti (L.) from Santiago de Cuba, Cuba, with a high level of temephos resistance (19.58x at the 50% lethal concentration [LC50]), was subjected to temephos selection to evaluate the utility of this organophosphate insecticide for mosquito control. High resistance developed after six generations of selection (200.00x). Little or no cross-resistance was observed to the organophosphates, malathion and fenitrothion, but high cross-resistance was observed for the pyrethroid deltamethrin (337.5x) and the organophosphate fenthion (12.74x). Synergism tests implicated detoxifying esterases in temephos and fenthion resistance and deltamethrin resistance was associated with a cytochrome P450 monooxygenasa. Biochemical tests, polyacrylamide gel electrophoresis (PAGE), and inhibition studies confirmed the presence of elevated esterase activity associated with temephos resistance. Pyrethroid resistance could be associated with a glutathione-S-transferase mechanism but not the esterases. The cross-resistance to deltamethrin from temephos selection could limit the use of both insecticides for Ae. aegypti control.

Adaptación de los métodos en placas de microtitulación para la cuantificación de la actividad de esterasas y glutation-s-transferasa en Aedes aegypti / Modification of microtitration plate methods for quantification of esterases and glutathione-s-transferase activity in Aedes aegypti

Se modificaron las técnicas de detección de la actividad de esterasas inespecíficas y de la glutation-s-transferasa, utilizadas en Culex quinquefasciatus, para su detección en Aedes aegypti (L.). Se determinaron para cada una de las enzimas, los valores de concentración óptima de sustrato (concentración saturante) y de tiempo óptimo de lectura de la reacción, mediante la utilización de 4 cepas de Aedes aegypti, 1 de Cuba, 2 de Venezuela y 1 cepa susceptible de referencia. La frecuencia de esterasas inespecíficas resultó ser en MIRANDA de 0,76 en ARAGUA 0,42 y en SANTIAGO DE CUBA se obtuvo el valor máximo de frecuencia de este mecanismo. Para el mecanismo de glutation-s-transferasa la frecuencia resultó ser de 0,45 en ARAGUA, 0,043 en MIRANDA y en SANTIAGO de CUBA de 1. Por primera vez en Cuba se pudo disponer de una batería de técnicas bioquímicas para la detección de los mecanismos de resistencia en Aedes aegypti, esto permitió conformar una base sólida para la detección rápida y temprana de la resistencia en esta especie, principal vector del dengue en las Américas

Esterasas elevadas como mecanismo de resistencia a insecticidas organofosforados en cepas de Aedes aegypti / Elevated esterases as a mechanism of resistance to organophosphate insecticides in Aedes aegypti strains

Fueron evaluadas 5 cepas de Aedes aegypti L., 1 de Cuba y 4 de Venezuela, para determinar sus niveles de resistencia a insecticidas organofosforados (temefos, clorpirifos y pirimifos metil). En las cepas venezolanas se encontró resistencia a temefos, solo en la cepa APURE. En las cepas de TACHIRA y MIRANDA se observaron moderados valores de resistencia (FR50 entre 5 y 10 x) para clorpirifos, y altos niveles de resistencia (FR >10x) fueron obtenidos para este insecticida en la cepa de ARAGUA. Todas las cepas venezolanas mostraron elevados niveles de resistencia a pirimifos metil. La cepa cubana, colectada en SANTIAGO de CUBA, mostró moderados niveles de resistencia a temefos y pirimifos metil, y altos niveles para clorpirifos. Los resultados de las pruebas bioquímicas demostraron la presencia de los mecanismos de esterasas y glutation-s-transferasa, a elevada frecuencia en casi todas las cepas. Mediante electroforesis en gel de poliacrilamida se observó una banda fuertemente teñida en todas las cepas, con un valor de Rf de 0,779, que se nombró esterasa A4, y no se observó en la cepa de referencia susceptible a insecticidas. El significado de esta esterasa en la resistencia a insecticidas organofosforados está aún por demostrar. La resistencia a estos insecticidas en Ae. aegypti es un problema serio para las operaciones de control de esta especie, por lo que se sugirieron estrategias de control integradas que permitan evitar o retardar la aparición de esta en Cuba y Venezuela

Análisis comparativo de la resistencia a insecticidas en cepas de Culex quinquefasciatus, provenientes de Camagüey / Comparative analysis of resistance to insecticides in strains of Culex quinquefasciatus, from Camagüey

The organophosphate, carbamate and pyrethroid resistance levels in 14 strains of Culex quinquefasciatus from Camagüey were studied by bioassays and biochemical tests in larvae with or without synergists. The use of electrophoresis in polyacrylamide gel (PAGE) allowed to identify 8 patterns of esterases, among which A3A6B6, BiB6 and B1A6B6 were the most frequent. It was observed that 6 years after the suspension of malathion, there is still resistance to this product. There was also cross resistance to propoxur. Detoxification mechanisms for deltamethryn are being developed. The most important physiological mechanisms were: elevated esterases in the resistance to malathion, modified AchE for propoxur and oxidases of multiple function for deltamethryn. In relation to the genic frequencies, the modified AchE mechanisms was more extended than that of the elevated esterases in these populations of mosquitoes of the central region of Cuba.

Determinación de la resistencia a insecticidas y sus mecanismos bioquímicos en 2 cepas de Culex quinquefasciatus procedentes de Santiago de Cuba / Determination of the resistance to insecticides and their biochemical mechanisms in 2 strain of culex quinquefasciatus fron Santiago de Cuba

Se analizó el comportamiento de la resistencia a 3 insecticidas organofosforados (malation, clorpirifos y pirimifos metil), 3 piretroides (deltametrina, lambdacialotrina y cipermetrina) y 1 carbamato (propoxur) en poblaciones de Culex quinquefasciatus provenientes de 2 municipios de la provincia de Santiago de Cuba. Los valores del factor de resistencia determinaron que existe resistencia para malatión y clorpirifos. Sin embargo, a pesar de la existencia de una alta frecuencia en los mecanismos de esterasas elevadas y acetilcolinesterasa alterada, no se observó resistencia a pirimifos metil, lo cual corroboró la no afectación de este insecticida por estos mecanismos seleccionados en nuestras poblaciones de Culex quinquefasciatus. Se observó resistencia a los insecticidas piretroides deltametrina y lambdacialotrina en Santiago de Cuba, y moderada para cipermetrina en Santiago y San Luis; también se encontró en San Luis resistencia a deltametrina, pero moderada a lambdacialotrina. Los resultados obtenidos a partir del uso de los sinergistas S,S,S, tributil fosfotritiado (DEF) y piperonil butóxido (PB) indicaron que los mecanismos de resistencia de esterasas inespecíficas y las oxidasas de función múltiple están involucradas en la resistencia a piretroides en ambas cepas provenientes de Santiago de Cuba y San Luis. Se determinó, mediante las pruebas bioquímicas, que existió una alta frecuencia de los mecanismos de esterasas y acetilcolinesterasa alterada. Los resultados de las electroforesis en gel de poliacrilamida (PAGE), mostraron que la esterasa B1 aparece con mayor frecuencia asociada con las esterasas A6 y B6. Se infirió que esta asociación pudiera estar vinculada con la resistencia a piretroides

Evolución de la resistencia en una cepa de Culex quinquefasciatus a partir de la selección con el insecticida piretroide lambdacialotrina

Se estudiaron los cambios en la resistencia a diferentes insecticidas en una cepa de Culex quinquefasciatus seleccionada en el laboratorio con dosis del piretroide lambdacialotrina que provocaran el 90 % de mortalidad en larvas. Se logró un aumento de la resistencia a este insecticida de 144,5 veces respecto al nivel original, y se obtuvo una cepa resistente (287x). También aumentaron los niveles de resistencia a metilpirimifos (2.4 veces), propoxur (6 veces), DDT (5,2 veces), clorpirifos (22 veces), cipermetrina (67,5 veces) y deltametrina (20,2 veces). Las frecuencias de los genes que codifican para las enzimas esterasas elevadas y acetilcolinesterasa modificada alcanzaron su máximo valor y se observaron cambios notables en los fenotipos para esterasas en las electroforesis en geles de poliacrilamida. Se detectó sinergismo de DEF y PB con lambdacialotrina, por lo que las esterasas elevadas y las esterasas de función múltiple pueden contribuir a la resistencia.

The resistance change to different insecticides in Culex quinquesfasciatus strain select at the laboratory with doses of pyrethroid lambda-cyhalothrin that would cause a larva mortality of 90 % were studied. It was attained an increase of the resistance to this insecticide of 144.5 times compared with the original level, and it was obtained a resistant strain (287x). There was an increase of the levels of resistance to methyl-pyrimifos (2.4 times), propoxur (6 times), DDT (5,2 times), clorpirifos (22 time), cypermethrin (67.5 times), and deltamethrin (20.2 times). The frecuencies of the genes that codify for the elevated esterases enzymes and for the modified acetylcholinesterase reached their maximum value. Significant changes were observed in the phenotypes for esterases in the electrophoresis in polyacralamide gels. It was detected synergism of DEF and PB with lambda-cyhalothrin. Therefore, the elevated esterases and the esterases of multiple function may contribute to resistance.

Documento de trabajo Nº7 sobre tecnicas e instrumentos de evaluacion

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