Evaluation of the biological efficacy and susceptibility in Aedes aegypti to the pyrethroid insecticides deltamethrin and cyfluthrin during the Zika virus outbreak in Kuna Yala, Panama / Evaluación de la eficacia biológica y de la sensibilidad de Aedes aegypti a los insecticidas piretroides deltametrina y ciflutrina durante el brote del virus Zika en Kuna Yala, Panamá.

Introduction. The development of resistance to insecticides in Aedes aegypti represents a major threat to public health. Surveillance and monitoring of the behavior of bioefficacy and susceptibility of insecticides is of fundamental importance to prolong the useful life of insecticide molecules. Objective. To evaluate the bioefficacy and susceptibility of the insecticides deltamethrin and cyfluthrin in Aedes aegypti during the zika epidemic outbreak in Kuna Yala, Panama. Methods and materials. The bioefficacy and susceptibility of deltamethrin and cyfluthrin in Aedes aegypti Ustupo using WHO standardized bioassays during the Zika epidemic outbreak in Kuna Yala, Panama. Results. In the bioassays with Aedes aegypti Ustupo, possible resistance to deltamethrin and cyfluthrin was observed, with a mortality rate of 95,3% and 94%, respectively. The bioefficacy results with Aedes aegypti Ustupo registered low bioefficacy of deltamethrin and cyfluthrin with average percentages of mortality in the intradomicile of 75% and 31,1%, respectively, while in the peridomicile it was 63,7% and 26,1%, respectively. Conclusion. The results of this study represent a challenge that the National Aedes Control Program must face in order to care for and maintain the toxic effect of insecticides applied against Aedes populations. It is necessary for the National Aedes Control Program to establish a resistance management program to evaluate resistance and its distribution in order to guarantee the sustainability of anti-vector interventions against Aedes populations.

Introducción. El desarrollo de la resistencia a insecticidas de Aedes aegypti representa una gran amenaza para la salud pública. La vigilancia y el monitoreo de la eficacia biológica a los insecticidas y la sensibilidad de las poblaciones de Aedes aegypti es de fundamental importancia para prolongar la vida útil de estas moléculas. Objetivo. Evaluar la eficacia biológica de los insecticidas deltametrina y ciflutrina y la sensibilidad de poblaciones de Aedes aegypti a estos insecticidas durante el brote epidémico de virus del Zika en Kuna Yala, Panamá. Métodos y materiales. Se evaluó la eficacia biológica de la deltametrina y la ciflutrina, y la sensibilidad a estos insecticidas de poblaciones de la cepa Aedes aegypti Ustupo, mediante bioensayos estandarizados por la Organización Mundial de la Salud durante el brote epidémico de virus del Zika en Kuna Yala, Panamá. Resultados. En los bioensayos con Aedes aegypti Ustupo se observó posible resistencia a deltametrina y a ciflutrina con un porcentaje de mortalidad del 95,3 y 94 %, respectivamente. Se registró baja eficacia biológica con la cepa Aedes aegypti Ustupo para la deltametrina y la ciflutrina, con medias de porcentajes de mortalidad de 75 y 31,1 %, en el intradomicilio, mientras que en el peridomicilio fue de 63,7 y 26,1 %, respectivamente. Conclusión. Los resultados de este estudio representan un desafío que debe enfrentar el Programa Nacional de Control de Aedes para lograr cuidar y mantener el efecto tóxico de los insecticidas aplicados contra las poblaciones de Aedes. Es necesario que el Programa Nacional de Control de Aedes establezca unos lineamientos de manejo de la resistencia para caracterizarla y evaluar la distribución geográfica de las poblaciones afectadas. Lo anterior con el propósito de garantizar la sostenibilidad de las intervenciones antivectoriales contra las poblaciones de Aedes.

Evaluación de la eficacia biológica y de la sensibilidad de Aedes aegypti a los insecticidas piretroides deltametrina y ciflutrina durante el brote del virus Zika en Kuna Yala, Panamá / Evaluation of the biological efficacy and susceptibility in Aedes aegypti to the pyrethroid insecticides deltamethrin and cyfluthrin during the Zika virus outbreak in Kuna Yala, Panama

Introducción. El desarrollo de la resistencia a insecticidas de Aedes aegypti representa una gran amenaza para la salud pública. La vigilancia y el monitoreo de la eficacia biológica a los insecticidas y la sensibilidad de las poblaciones de Aedes aegypti es de fundamental importancia para prolongar la vida útil de estas moléculas. Objetivo. Evaluar la eficacia biológica de los insecticidas deltametrina y ciflutrina y la sensibilidad de poblaciones de Aedes aegypti a estos insecticidas durante el brote epidémico de virus del Zika en Kuna Yala, Panamá. Materiales y métodos. Se evaluó la eficacia biológica de la deltametrina y la ciflutrina, y la sensibilidad a estos insecticidas de poblaciones de la cepa Aedes aegypti Ustupo, mediante bioensayos estandarizados por la Organización Mundial de la Salud durante el brote epidémico de virus del Zika en Kuna Yala, Panamá. Resultados. En los bioensayos con Aedes aegypti Ustupo se observó posible resistencia a deltametrina y a ciflutrina con un porcentaje de mortalidad del 95,3 y 94 %, respectivamente. Se registró baja eficacia biológica con la cepa Aedes aegypti Ustupo para la deltametrina y la ciflutrina, con medias de porcentajes de mortalidad de 75 y 31,1 %, en el intradomicilio, mientras que en el peridomicilio fue de 63,7 y 26,1 %, respectivamente. Conclusión. Los resultados de este estudio representan un desafío que debe enfrentar el Programa Nacional de Control de Aedes para lograr cuidar y mantener el efecto tóxico de los insecticidas aplicados contra las poblaciones de Aedes. Es necesario que el Programa Nacional de Control de Aedes establezca unos lineamientos de manejo de la resistencia para caracterizarla y evaluar la distribución geográfica de las poblaciones afectadas. Lo anterior con el propósito de garantizar la sostenibilidad de las intervenciones antivectoriales contra las poblaciones de Aedes.

Introduction. The development of resistance to insecticides in Aedes aegypti represents a major threat to public health. Surveillance and monitoring of the biological efficacy and sensibility of Aedes aegypti populations to insecticides is fundamental to prolong the useful life of insecticide molecules. Objective. To evaluate the biological efficacy of deltamethrin and cyfluthrin and sensibility to insecticides in Aedes aegypti during the zika epidemic outbreak in Kuna Yala, Panama. Materials and methods. We assessed the biological efficacy of deltamethrin and cyfluthrin, and sensibility in the strain Aedes aegypti Ustupo using bioassays standardized by the World Health Organization during the Zika epidemic outbreak in Kuna Yala, Panama. Results. In the bioassays with Aedes aegypti Ustupo, we observed a possible resistance to deltamethrin and cyfluthrin with a mortality rate of 95,3 and 94%, respectively. The obtained results registered low biological efficacy of deltamethrin and cyfluthrin with average percentages of mortality of 75 and 31.1% in the intradomicile, and 63,7 and 26.1% in the peridomicile. Conclusion. The results of this study represent a challenge for the National Aedes Control Program to care for and maintain the toxic effect of insecticides applied against Aedes populations. There is a need for the National Aedes Control Program to establish some guidelines about resistance assessment and resistant populations' geographic distribution to guarantee the sustainability of anti-vector interventions against Aedes populations.

Population Dynamics of Anopheles albimanus (Diptera: Culicidae) at Ipetí-Guna, a Village in a Region Targeted for Malaria Elimination in Panamá.

Anopheles albimanus Wiedemann is a major malaria vector in Mesoamerica and the Caribbean whose population dynamics, in response to changing environments, has been relatively poorly studied. Here, we present monthly adult and larvae data collected from May 2016 to December 2017 in Ipetí-Guna, a village within an area targeted for malaria elimination in the República de Panamá. During the study period we collected a total of 1678 Anopheles spp. mosquitoes (1602 adults and 76 larvae). Over 95% of the collected Anopheles spp. mosquitoes were An. albimanus. Using time series analysis techniques, we found that population dynamics of larvae and adults were not significantly correlated with each other at any time lag, though correlations were highest at one month lag between larvae and adults and four months lag between adults and larvae. Larvae population dynamics had cycles of three months and were sensitive to changes in temperature with 5 months lag, while adult abundance was correlated with itself (1 month lag) and with the normalized difference vegetation index (NDVI) with three months lag. A key observation from our study is the absence of both larvae and adults of An. albimanus between January and April from environments associated with Guna population's daily activities, which suggests this time window could be the best time to implement elimination campaigns aimed at clearing Plasmodium spp. parasites from Guna populations using, for example, mass drug administration.

Short-term suppression of Aedes aegypti using genetic control does not facilitate Aedes albopictus.

BACKGROUND: Under permit from the National Biosafety Commission for the use of genetically modified organisms, releases of a genetically engineered self-limiting strain of Aedes aegypti (OX513A) were used to suppress urban pest Ae. aegypti in West Panama. Experimental goals were to assess the effects on a coexisting population of Ae. albopictus and examine operational parameters with relevance to environmental impact. RESULTS: Ae. albopictus populations were shown to be increasing year upon year at each of three study sites, potentially reflecting a broader-scale incursion into the area. Ae. albopictus abundance was unaffected by a sustained reduction in Ae. aegypti by up to 93% through repeated releases of OX513A. Males accounted for 99.99% of released OX513A, resulting in a sustained mating fraction of 75%. Mean mating competitiveness of OX513A was 0.14. The proportion of OX513A in the local environment decreased by 95% within 25 days of the final release. CONCLUSIONS: There was no evidence for species replacement of Ae. aegypti by Ae. albopictus over the course of this study. No unintentional environmental impacts or elevated operational risks were observed. The potential for this emerging technology to mitigate against disease outbreaks before they become established is discussed.