Bioassays were performed in order to detect the susceptibility of Aedes aegypti to the chemical insecticides temephos and cypermethrin. The results showed that this species is susceptible to temephos and presents resistance to cypermethrin.The strategies for controlling the principal vector of dengue, Aedes aegypti, are based on the utilization of chemical and biological products, integrated with environmental management programs. In Brazil, the programs that aim to control Aedes aegypti mainly utilize chemical insecticides, among which organophosphates (OP) and pyrethroids (P) are prominent. These programs require constant monitoring.The numbers of dengue cases are rising every year, and different factors influence this increase. Resistance to chemical products may favor an increase in the mosquito populations, thereby resulting in increases in the numbers of dengue cases. 1,4 For this reason, it is important to perform periodic monitoring of the susceptibility to insecticides of the populations implicated in the transmission of this disease. 3 This study presents data on the susceptibility of a population of Aedes aegypti in the city of Curitiba, State of Paraná, for the first time. This population was submitted to two chemical insecticides: temephos (organophosphate) and cypermethrin (pyrethroid). The resistance ratio was compared with the data for the standard colony at the Centers for Disease Control and Prevention (CDC).Immature specimens were collected from different districts of Curitiba between January and April 2003.Aedes aegypti was only found in the sample from the Uberaba district, in an artificial breeding ground (automobile wreckage in a scrap metal yard). This was the only population originating from Curitiba utilized in the susceptibility tests.The lineage utilized for making the comparison was the Rockefeller CDC. The insecticides utilized in the bioassays were temephos, "Temephos Fersol 1G" (granulated, 1%), and cypermethrin, "Cynoff 400 Pm" (powder, 25%). These products were diluted in mineral water to prepare the standard solutions with the same concentration of 50 ppm of active ingredient.The process for the bioassays followed the standards of the World Health Organization (WHO). 5 The results were submitted to Probit analysis. 2 The following criteria were utilized for determining the resistance: if the mortality rate was greater than or equal to 98%, the sample was considered to susceptible; if the mortality rate was 80 to 97%, the response was checked by repeating the experiment; and if the mortality rate was less than 80%, the sample was considered to be resistant. 5 A total of 750 larvae were analyzed in relation to cypermethrin and 700 in relation to temephos, in-
Aedes aegypti and Aedes albopictus (Diptera: Culicidae): coexistence and susceptibility to temephos, in municipalities with occurrence of dengue and differentiated characteristics of urbanizationAedes aegypti e Aedes albopictus (Diptera: Culicidae): coexistência e suscetibilidade ao temephos, em municípios com ocorrência de casos de dengue e diferentes características de urbanização
Introduction: Understanding Aedes (Stegomyia) aegypti (L) behavior will provide insight into the design of entomological surveillance devices. Objective: Design and build a trap for surveillance Aedes aegypti. Methodology: We examined egg-laying preference and the ability to capture adult Ae. aegypti using containers that differed in shape, color and internal retention systems. The characteristics most effective in capturing adult mosquitoes were used to develop a prototype efficient in trapping mosquitoes. The shape of the prototype was determined by examining oviposition preference of containers having circular, square and triangular bases. Color discrimination was assessed by covering the bodies of the containers in green (523 nm), red (621 nm), white and gray (the chromatic scale from black to white). The propensity of Ae. aegypti to enter the containers was assessed by incorporating an entrance to the container in the shape of an inverted truncated oblique pyramid with base, middle and apex dimensions of 6.5-4 cm, 5-2.5 cm and 4.5-1.5 cm, respectively. All variables as the number of egg and adults captured in treatments were subjected to variance analysis; only data with P < 0.05 were considered significant. Results: Our results indicate that neither shape nor entrance dimension attract ovipositing Ae. The final design of the trap resembled a truncated pyramid with a red square base, a black oblique entrance of 5 x 2.5 cm and an internal retention system. The final prototype had a capture rate of 90.5 ± 5% under laboratory conditions.
Diferentes estudios han evaluado la actividad biocida de aceites esenciales (AEs) en larvas de mosquitos de importancia médica. Sin embargo, son limitadas las investigaciones que analizan los efectos de los AEs en todos los estadíos del ciclo de vida de Aedes aegypti. Este estudio evalúa la actividad biológica del AE de Salvia officinalis frente a Ae. aegypti. Se evaluó la actividad ovicida a concentraciones de 1, 5, 37 y 50 mg.L-1 en huevos de 0-12 h y huevos de 0-72 h. La actividad larvicida, pupicida y adulticida fue evaluada a concentraciones exploratorias (CE) y múltiples. Para la actividad repelente se empleó una CE de 1.000 mg.L-1 en intervalos de 0-2 min y de 2-15 min de exposición en antebrazos de voluntarios. La actividad disuasiva de oviposición se estimó a CE de 5, 50 y 200 mg.L-1. El AE causó malformaciones en embriones y alteración de las larvas. La mayor actividad larvicida fue a 63 y 76 mg.L-1 (27 ± 13,4 y 37 ± 18,6 %) a 24 h. La mayor mortalidad pupicida fue a 310 y 390 mg.L-1 (89 ± 1,53 and 100 ± 0 %) a las 48 h. La mortalidad adulticida a 300 mg.L-1 fue de 57,5 ± 0 % y el porcentaje de repelencia fue de 42 ± 4,7 %. La acción disuasiva a 200 mg.L-1 fue de 97 ± 4,81 %, con un índice de actividad de ovipostura de -0,94. S. officinalis mostró un efecto biocida en embriones y mortalidad de pupas y adultos, lo que revela que tiene un uso potencial en programas de control focalizados en estos estadios de desarrollo.
Introducción: Desde la introducción en América de Virus Chikungunya (CHIKV) en el 2013, se ha convertido en un problema de salud pública en el mundo por la morbilidad y la carga económica que genera. El diagnóstico de laboratorio es una herramienta vital en la evaluación de la enfermedad y de las posibles complicaciones, así como en la vigilancia de la infección en el vector. Objetivo: Estandarizar una técnica de Reacción en Cadena de la Polimerasa Transcriptasa Reversa (RT-PCR) en tiempo real para la detección de CHIKV. Materiales y métodos: Se obtuvieron muestras sanguíneas de personas con fiebre y exantema residentes en el Área Metropolitana de Bucaramanga. Se hizo extracción de RNA viral con estuche de Qiagen. Se probaron tres técnicas reportadas en literatura, de RT-PCR en tiempo real SYBR Green One-Step, la de Ho que amplifica un fragmento del gen de la proteína nsP2 y las de Ummul y Agarwal del gen de la proteína E1. Se usó el equipo StepOnePlus de Applied Biosystem. Resultados: En una muestra se detectó CHIKV por las técnicas de Ummul (Ct 27,14) y de Agarwal (Ct 26,78). Ho mostró resultados inespecíficos (Ct 35,85 y 36,97). Conclusiones: Las técnicas que permitieron detectar CHIKV fueron Ummul y Agarwal, siendo congruente con los límites de detección reportados en la literatura (4,12 x 100 copias RNA/ml y 100 copias/25ml, respectivamente). Considerando lo reportado por Ho se asume que la cantidad de RNA viral presente en la muestra es menor al detectado por esta técnica (102 PFU/ml).
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