Anopheles albimanus (Diptera: Culicidae) Ensemble Distribution Modeling: Applications for Malaria Elimination.

In the absence of entomological information, tools for predicting Anopheles spp. presence can help evaluate the entomological risk of malaria transmission. Here, we illustrate how species distribution models (SDM) could quantify potential dominant vector species presence in malaria elimination settings. We fitted a 250 m resolution ensemble SDM for Anopheles albimanus Wiedemann. The ensemble SDM included predictions based on seven different algorithms, 110 occurrence records and 70 model projections. SDM covariates included nine environmental variables that were selected based on their importance from an original set of 28 layers that included remotely and spatially interpolated locally measured variables for the land surface of Costa Rica. Goodness of fit for the ensemble SDM was very high, with a minimum AUC of 0.79. We used the resulting ensemble SDM to evaluate differences in habitat suitability (HS) between commercial plantations and surrounding landscapes, finding a higher HS in pineapple and oil palm plantations, suggestive of An. albimanus presence, than in surrounding landscapes. The ensemble SDM suggested a low HS for An. albimanus at the presumed epicenter of malaria transmission during 2018-2019 in Costa Rica, yet this vector was likely present at the two main towns also affected by the epidemic. Our results illustrate how ensemble SDMs in malaria elimination settings can provide information that could help to improve vector surveillance and control.

Trade, uneven development and people in motion: Used territories and the initial spread of COVID-19 in Mesoamerica and the Caribbean.

Mesoamerica and the Caribbean form a region comprised by middle- and low-income countries affected by the COVID-19 pandemic differently. Here, we ask whether the spread of COVID-19, measured using early epidemic growth rates (r), reproduction numbers (R t ), accumulated cases, and deaths, is influenced by how the 'used territories' across the regions have been differently shaped by uneven development, human movement and trade differences. Using an econometric approach, we found that trade openness increased cases and deaths, while the number of international cities connected at main airports increased r, cases and deaths. Similarly, increases in concentration of imports, a sign of uneven development, coincided with increases in early epidemic growth and deaths. These results suggest that countries whose used territory was defined by a less uneven development were less likely to show exacerbated COVID-19 patterns of transmission. Health outcomes were worst in more trade-dependent countries, even after controlling for the impact of transmission prevention and mitigation policies, highlighting how structural effects of economic integration in used territories were associated with the initial COVID-19 spread in Mesoamerica and the Caribbean.

Modeling the association between Aedes aegypti ovitrap egg counts, multi-scale remotely sensed environmental data and arboviral cases at Puntarenas, Costa Rica (2017-2018).

Problems with vector surveillance are a major barrier for the effective control of vector-borne disease transmission through Latin America. Here, we present results from a 80-week longitudinal study where Aedes aegypti (L.) (Diptera: Culicidae) ovitraps were monitored weekly at 92 locations in Puntarenas, a coastal city in Costa Rica with syndemic Zika, chikungunya and dengue transmission. We used separate models to investigate the association of either Ae. aegypti-borne arboviral cases or Ae. aegypti egg counts with remotely sensed environmental variables. We also evaluated whether Ae. aegypti-borne arboviral cases were associated with Ae. aegypti egg counts. Using cross-correlation and time series modeling, we found that arboviral cases were not significantly associated with Ae. aegypti egg counts. Through model selection we found that cases had a non-linear response to multi-scale (1-km and 30-m resolution) measurements of temperature standard deviation (SD) with a lag of up to 4 weeks, while simultaneously increasing with finely-grained NDVI (30-m resolution). Meanwhile, median ovitrap Ae. aegypti egg counts increased, and respectively decreased, with temperature SD (1-km resolution) and EVI (30-m resolution) with a lag of 6 weeks. A synchrony analysis showed that egg counts had a travelling wave pattern, with synchrony showing cyclic changes with distance, a pattern not observed in remotely sensed data with 30-m and 10-m resolution. Spatially, using generalized additive models, we found that eggs were more abundant at locations with higher temperatures and where EVI was leptokurtic during the study period. Our results suggest that, in Puntarenas, remotely sensed environmental variables are associated with both Ae. aegypti-borne arbovirus transmission and Ae. aegypti egg counts from ovitraps.

Health policy impacts on malaria transmission in Costa Rica.

Costa Rica is near malaria elimination. This achievement has followed shifts in malaria health policy. Here, we evaluate the impacts that different health policies have had on malaria transmission in Costa Rica from 1913 to 2018. We identified regime shifts and used regression models to measure the impact of different health policies on malaria transmission in Costa Rica using annual case records. We found that vector control and prophylactic treatments were associated with a 50% malaria case reduction in 1929-1931 compared with 1913-1928. DDT introduction in 1946 was associated with an increase in annual malaria case reduction from 7.6% (1942-1946) to 26.4% (1947-1952). The 2006 introduction of 7-day supervised chloroquine and primaquine treatments was the most effective health policy between 1957 and 2018, reducing annual malaria cases by 98% (2009-2018) when compared with 1957-1968. We also found that effective malaria reduction policies have been sensitive to natural catastrophes and extreme climatic events, both of which have increased malaria transmission in Costa Rica. Currently, outbreaks follow malaria importation into vulnerable areas of Costa Rica. This highlights the need to timely diagnose and treat malaria, while improving living standards, in the affected areas.

Co-occurrence of kdr Mutations V1016I and F1534C and Its Association With Phenotypic Resistance to Pyrethroids in Aedes aegypti (Diptera: Culicidae) Populations From Costa Rica.

Aedes aegypti (Linnaeus, 1762) is considered the most important mosquito vector species for several arboviruses (e.g., dengue, chikungunya, Zika) in Costa Rica. The primary strategy for the control and prevention of Aedes-borne diseases relies on insecticide-based vector control. However, the emergence of insecticide resistance in the mosquito populations presents a significant threat to these prevention actions. The characterization of the mechanisms driving the insecticide resistance in Ae. aegypti is vital for decision making in vector control programs. Therefore, we analyzed the voltage-gated sodium channel (VGSC) gene for the presence of the V1016I and F1534C kdr mutations in Ae. aegypti populations from Puntarenas and Limon provinces, Costa Rica. The CDC bottle bioassays showed that both Costa Rican Ae. aegypti populations were resistant to permethrin and deltamethrin. In the case of kdr genotyping, results revealed the co-occurrence of V1016I and F1534C mutations in permethrin and deltamethrin-resistant populations, as well as the fixation of the 1534C allele. A strong association between these mutations and permethrin and deltamethrin resistance was found in Puntarenas. Limon did not show this association; however, our results indicate that the Limon population analyzed is not under the same selective pressure as Puntarenas for the VGSC gene. Therefore, our findings make an urgent call to expand the knowledge about the insecticide resistance status and mechanisms in the Costa Rican populations of Ae. aegypti, which must be a priority to develop an effective resistance management plan.

Parasite Removal for Malaria Elimination in Costa Rica.

In Costa Rica, malaria parasite removal via treatment shift and focalized mass drug administration (MDA) largely decreased malaria transmission between 2006 and 2009, and led to malaria elimination from 2013 to 2015. These results can help to shape a regional strategy for malaria elimination in Mesoamerica and México.

Nuevos registros de Aedes albopictus (Skuse) en cuatro localidades de Costa Rica / New records of Aedes albopictus (Skuse) in four locations of Costa Rica

Resumen Introducción Aedes albopictus (Skuse) es un vector de arbovirus ampliamente distribuido. En Costa Rica, la expansión geográfica de Ae. albopictus se ha incrementado en la última década, por lo que es importante actualizar el conocimiento sobre su distribución. Objetivo Informar sobre el hallazgo de Aedes albopictus en nuevas localidades de Costa Rica. Materiales y Métodos Se colectaron formas inmaduras de mosquitos con morfología sugestiva de Ae. albopictus en localidades de las provincias de Puntarenas (isla de Chira y Golfito), Guanacaste (Liberia), Alajuela (Upala), San José (Acosta) y Heredia (Sarapiquí). Los especímenes fueron fijados en etanol al 70%, aclarados en lactofenol e identificados con el uso de claves dicotómicas. Resultados Las especies identificadas fueron Ae. albopictus, Aedes aegypti, Haemagogus equinus y Haemagogus iridocolor-H. lucifer. Las de Ae. albopictus procedieron de los siguientes depósitos: recipiente plástico, tanque de agua, lona plástica, balde, llanta, canoa, piscina, maceta y bota de hule. Se reporta la presencia de Ae. albopictus en Liberia (Guanacaste), isla de Chira y Golfito (Puntarenas) y Upala (Alajuela). Conclusiones Se evidencia la expansión que ha experimentado Ae. albopictus en Costa Rica. Se enfatiza la necesidad de un diagnóstico microscópico certero, pues las larvas de Ae. albopictus pueden coexistir con otras especies que resultan difíciles de diferenciar, tales como Ae. aegypti y algunas especies de Haemagogus. Considerando que Ae. albopictus es un vector competente para virus dengue (DENV), chikungunya (CHIKV) y Zika (ZIKV), se recomienda investigar su papel en la transmisión de virus en estas zonas, así como el desplazamiento y/o coexistencia con especies como Ae. aegypti.

Abstract Introduction Aedes albopictus (Skuse) is a vector of arboviruses that is widely-distributed. In Costa Rica the geographical expansion of Ae. albopictus has increased in the past decade, which requires updating knowledge about its distribution. Objective To report the finding of Aedes albopictus in new localities of Costa Rica. Materials and Methods Immature stages of mosquitoes that were morphologically suggestive of Ae. albopictus were collected in localities of the provinces of Puntarenas (Chira island and Golfito), Guanacaste (Liberia), Alajuela (Upala), San José (Acosta) and Heredia (Sarapiquí). Specimens were fixed in 70 % ethanol, cleared in lactophenol, and identified using dichotomous keys. Results The species identified were: Ae. albopictus, Aedes aegypti, Haemagogus equinus, and Haemagogus iridocolor-H. Lucifer. The ones of Ae. albopictus were in the following container types: plastic container, water tank, plastic tarp, bucket, tire, roof gutter, swimming pool, flower pot and rubber boot. This is the first scientific report of Ae. albopictus in Liberia (Guanacaste), Chira island and Golfito (Puntarenas), and Upala (Alajuela). Conclusions There is evidence of the expansion of Ae. albopictus in Costa Rica. Emphasis is given as to the need for a precise microscopical diagnosis, since Ae. albopictus larvae may coexist with other species that may be difficult to differentiate, such as Ae. aegypti and some species of Haemagogus. Considering that Ae. albopictus is a competent vector for dengue (DENV), chikungunya (CHIKV), and Zika (ZIKV) viruses, further investigation of its role in virus transmission is recommended in these areas, as well as displacement and/or coexistence with species like Ae. aegypti.

Sitios de cría de Aedes aegypti (Linnaeus) en el cantón de Parrita, provincia de Puntarenas, Costa Rica, junio 2013 / Breeding sites for Aedes aegypti (Linnaeus) in the area of Parrita, Puntarenas province, Costa Rica, June 2013

ResumenIntroducción:En Costa Rica el dengue constituye la principal enfermedad de transmisión vectorial. El cantón de Parrita ha sido uno de los cantones con mayor notificación de dengue en los últimos años. En este cantón en el 2013 se reportaron 1120 casos de dengue, ocupando el número 18 entre los cantones del país con mayor notificación de casos. El control del dengue requiere un conocimiento integral de su principal vector Aedes aegypti, el cual utiliza gran variedad de recipientes artificiales para su cría.Objetivos:Identificar y describir los principales sitios de cría del Ae. aegypti en el cantón de Parrita que se encontraba en pleno brote de dengue durante las semanas epidemiológicas 23 y 24 en el año 2013.Material y Métodos:El muestreo entomológico fue realizado por 29 funcionarios de Manejo Integrado de Vectores del Ministerio de Salud. La presencia de al menos una larva de Ae. aegypti en cualquiera de los depósitos permitió designar al contenedor correspondiente como positivo.Resultados:En el período de estudio fueron detectados 918 criaderos o sitios de cría positivos por Ae. aegypti en un total de 5 027 casas visitadas. Se identificó́ la presencia de Ae. aegypti en todas las localidades trabajadas del cantón de Parrita, siendo los sitios de cría más frecuentes: tarros, baldes, llantas, chatarra mecánica y tanques.Discusión:Se evidencia que el control del Ae. aegypti debe hacerse de manera integral con énfasis en la coordinación intersectorial debido a la variedad y multicausalidad de los sitios de cría.

AbstractIntroduction: Dengue fever represents the main vector-borne illness in Costa Rica. The area called Parrita has been one of those with the highest reporting of dengue during the last few years. During 2013, in Parrita, there were 1120 reports of this illness and thus it came to occupy the 18th spot among the areas with the highest reporting of cases in the whole of Costa Rica. Control of dengue requires comprehensive knowledge of the main vector, Aedes aegypti, since this insect uses a large variety of artificial containers for its breeding.Objectives:To identify and describe the main breeding sites for Ae. aegypti in the area of Parrita which was in the midst of a full-blown outbreak of dengue fever during epidemiological weeks' number 23 and 24 in the year 2013.Materials and Methods:Entomological sampling was performed by 29 employees of the Integrated Vector Control Unit of the Ministry of Health. The presence of at least one Ae. aegypti larva in any of the containers was considered enough to designate this as a "positive" container.Results:During the study period, 918 breeding sites or sites positive for the vector were identified among a total of 5 027 homes visited. The presence of Ae. aegypti was confirmed in all the localities surveyed in the area of Parrita. The most frequent types of breeding sites were as follows: cans, buckets, tires, mechanical garbage and different types of tanks.Discussion:The conclusion is that there is evidence to suggest that the control of Ae. aegypti should be done in a comprehensive fashion with emphasis of inter-sectoral co-ordination due to the variety and multi-causality of the breeding sites.

Sitios de cría de Aedes aegypti (Linnaeus) y distribución geográfica de Aedes albopictus (Skuse) en la provincia de Limón, Costa Rica. 2012 / Breeding sites of Aedes aegypti (Linnaeus) and geographic distribution of Aedes albopictus (Skuse) in the province of Limón, Costa Rica. 2012

Introducción: en Costa Rica el dengue constituye la principal enfermedad de transmisión vectorial. Su control requiere un conocimiento integral de su principal vector Aedes aegypti, el cual utiliza gran variedad de recipientes artificiales para su cría. Aedes albopictus aunque no se ha relacionado con la trasmisión de esta enfermedad en las Américas, es un excelente vector en Asia y se reporta en Costa Rica desde finales de los 90. Objetivos: identificar y describir los principales sitios de cría del Ae. aegypti y la distribución geográfica de éste y del Ae. albopictus en la provincia de Limón en el año 2012. Métodos: todas las localidades de la provincia fueron muestreadas y visitadas en su totalidad al menos una vez cada cuatro meses por parte del personal de manejo integrado de vectores. En todas las visitas se buscaron todos los recipientes con agua, con presencia o no de larvas de Ae. aegypti y Ae. albopictus. Se tomaron muestras por cada tipo de recipiente donde se encontraron larvas. Resultados: se identificó la presencia de Ae. aegypti en los seis cantones de la provincia de Limón. Los sitios de cría más frecuentes fueron las llantas, los tanques y los baldes. Así mismo se identificó la presencia del Ae. albopictus en cinco de los seis cantones de la provincia. Conclusiones: en la provincia de Limón se encuentran año tras año los mismos sitios de cría del Ae. aegypti tanto en cantidad como en calidad. Así mismo se observa que la proliferación del Ae. aegypti está directamente relacionada con el ser humano, sus malos hábitos, y por la baja calidad de los servicios de salud de protección y mejoramiento del ambiente humano. Estos resultados demuestran que el abordaje del control del Ae. aegypti debe ser integral. Con el reporte del Ae. albopictus en este trabajo y el reporte en Siquirres en el 2009 se ha identificado a esta especie al menos una vez en todos los cantones de la provincia de Limón.

Introduction: dengue is the main vector-borne disease in Costa Rica. Control of dengue requires comprehensive knowledge about its main vector, Aedes aegypti, which may breed in a great variety of artificial containers. Aedes albopictus, on the other hand, has not been associated with dengue transmission in the Americas, but it is an efficient vector in Asia and its presence in Costa Rica has been reported since the late 1990s. Objectives: identify and describe the main breeding sites of Ae. aegypti and the geographic distribution of Ae. aegypti and Ae. albopictus in the province of Limón in the year 2012. Methods: all localities in the province were sampled and visited in their entirety at least once every four months by personnel from the integrated vector management program. During these visits, all containers with water were searched for the presence of Ae. aegypti and Ae. albopictus larvae. Samples were taken from each type of container where larvae were found. Results: Ae. aegypti was found to be present in the six cantons of the province of Limón. The most common breeding sites were pneumatic tires, water tanks and buckets. Aedes albopictus was found to be present in five of the six cantons. Conclusions: the same number and types of breeding sites of Ae. aegypti are found year after year in the province of Limón. It has also been noticed that proliferation of Ae. aegypti is directly related to human beings, their bad habits, and the poor quality of health services in charge of protecting and improving the human environment. These results show that control of Ae. aegypti should be approached in a comprehensive manner. With this report of Ae. albopictus and the 2009 report about Siquirres, the species has been identified at least once in all cantons of the province of Limón.

Primer hallazgo de Aedes albopictus Skuse en el Gran Área Metropolitana de Costa Rica / First finding of Aedesalbopictus Skuse in the the GreaterMetropolitan Area of Costa Rica

Objetivo: Informar sobre el primer hallazgo de Aedes albopictus en el Gran Área Metropolitana de Costa Rica. Métodos: Formas inmaduras de mosquitos colectadas en la Ciudadela La Carpio, Distrito Uruca, San José, como parte de una barrida epidemiológica fueron diagnosticadas preliminarmente como Ae. albopictus. Dicho material se fijó en alcohol al 70 %, se aclaró en lactofenol y se evaluó taxonómicamente mediante claves dicotómicas especializadas. Resultados: Las formas inmaduras evaluadas procedieron de dos criaderos, un tarro y un balde. Las características de las larvas y pupas permitieron identificarlas taxonómicamente como Ae. albopictus. Este es el primer reporte sobre la presencia de dicho vector en Costa Rica. Discusión: La presencia de Ae. albopictus en la Gran Área Metropolitana ocurre como parte del proceso de expansión que está teniendo dicho vector por el territorio nacional. Su presencia debe ser motivo de estudio para determinar su eventual papel en la transmisión del dengue. Por otro lado la presencia de este vector complica la gestión de la vigilancia entomológica de dengue que ha estado dirigida fundamentalmente a la identificación y control del Aedes aegypti.

Objective: To report the first finding of Aedes albopictus in the Greater Metropolitan Area of Costa Rica. Methods: Mosquito immature stages collected in the neighborhood La Carpio, District Uruca, San José, as part of an epidemiological intervention were diagnosed preliminarily as Ae. albopictus. This material was fixed in 70 % alcohol, cleared in lactophenol, and taxonomically evaluated using specialized dichotomous keys. Results: Larvae and pupae were collected from two types of breeding sites, a can and a bucket. The characteristics of the specimens allowed their taxonomic identification as Ae. albopictus. This is the first report of the presence of this vector in Costa Rica. Discussion: The presence of Ae. albopictus in the Greater Metropolitan Area occurs as part of the expansion of this vector throughout the country. This presence should be investigated to determine its possible role in the transmission of dengue. On the other hand, the presence of this vector complicates the management of entomological surveillance for dengue, because thus far it has been primarily aimed at the identification and control of Aedes aegypti.

Aedes albopictus y sus sitios de cría en la provincia de Limón, Costa Rica / Aedes albopictus and its breeding sites in the province of Limón, Costa Rica

Introducción: Aedes albopictus es un mosquito originario del sudeste asiático y vector del dengue, la fiebre amarilla, virus Chikungunya, y otros arbovirus. Objetivos: identificar la presencia del Aedes albopictus y describir sus principales sitios de cría en la provincia de Limón. Métodos: todas las localidades de la provincia fueron muestreadas y visitadas en su totalidad, al menos una vez cada 2 meses por parte del personal de manejo integrado de vectores. En cada visita se buscaban todos los recipientes con agua, con presencia o no de larvas de Aedes albopictus. Se tomaron muestras por cada tipo de recipiente donde se encontraron larvas. Resultados: se identificó la presencia de Aedes albopictus en el cantón de Pococí, no así en los 5 cantones restantes de la provincia de Limón. Se observó que los sitios de cría son variados, los depósitos artificiales constituyeron 50 %, mientras los naturales 39,28 % del total de positivos. Conclusiones: se demuestra la presencia del Aedes albopictus en el cantón de Pococí y se describen sus principales sitios de cría.

Introduction: Aedes albopictus, a mosquito native to Southeast Asia, is the vector of dengue, yellow fever, chikungunya fever and other arboviruses. Objectives: identify the presence of Aedes albopictus and describe its main breeding sites in the province of Limón. Methods: all areas in the province were sampled and visited in their entirety at least once every two months by personnel from the Integrated Vector Management Program. Visits included inspection of all water containers, irrespective of whether they contained Aedes albopictus larvae. Samples were taken from each type of container where larvae were found. Results: the presence of Aedes albopictus was identified in the municipality of Pococí, not in the other 5 municipalities in the province. It was found that there was a wide variety of breeding sites, 50 % of which were artificial and 39.28 % natural. Conclusions: presence of Aedes albopictus was identified in the municipality of Pococí and its main breeding sites described.

Sitios de Cría del Aedes Aegypti en la Región Pacífico Central de Costa Rica / Breeding site Aedes Aegypti in the Región Pacífico Central Costa Rica

En Costa Rica el dengue constituye la principal enfermedad retransmisión vectorial. Su control requiere un conocimiento integral de su vector Aedes aegypti, el cual utiliza gran variedad de recipientes artificiales para su cría. Objetivos: Identificar y describir los principales sitios de cría del Ae. aegyptien la Región Pacifico Central. Materiales y Métodos: El muestreo se realizó́ por el personal del programa de control de vectores durante el año 2011; de forma simultánea en los cantones que conforman la Región Pacifico Central. Resultados: Se identificó la presencia de Ae. aegypti en todos los cantones de la Región Pacifico Central. Los sitios de cría más frecuentes fueron, los tarros o depósitos inservibles, los baldes, las llantas, bebederos de animales y los tanques. Conclusiones: La proliferación del Ae. Aegypti está directamente relacionado con el hombre, sus malos hábitos, y por la calidad de los servicios de salud de protección y mejoramiento del ambiente humano. Estos resultados demuestran que el abordaje del control del Ae. aegypti debe ser integral.

Introduction: Dengue is the main disease due to vectorial transmission in Costa Rica. Its control requires comprehensive knowledge of its vector, which uses a wide variety of artificial containers for breeding. Objectives: To identify and describe Aedes aegypti breeding sites in the Central Pacific Region of Costa Rica. Materials and Methods: This survey was carried out by personnel of the vector control program working simultaneously, during the year 2011, in municipalities of the studied region. Results: We identified the presence of Ae. Aegypti in all municipalities in the Central Pacific Region of Costa Rica. The most frequent breeding sites were cans or unusable deposits, buckets, tires, troughs for animals and tanks. Conclusions: Proliferation of Ae. Aegypti is directly related to man, his bad habits, and to the quality of health care models regarding protection and improvement of the human environment. These results show that the approach to control Ae. aegypti must be comprehensive.

Sitios de Cría del Aedes aegypti en la Provincia de Limón, Costa Rica / Breeding sites of Aedes aegypti in the province of Limón, Costa Rica

En Costa Rica el dengue constituye la principal enfermedad de transmisión vectorial. Su control requiere un conocimiento integral de su vector Aedes aegypti, el cual utiliza gran variedad de recipientes artificiales para su cría. Objetivos: Identificar y describir los principales sitios de cría del A. aegypti en la provincia de Limón. Materiales y Métodos: El muestreo se realizó por el personal del programa de control de vectores durante el año 2011; de forma simultánea en los seis cantones que conforman la provincia de Limón. Resultados: Se identifico la presencia de A. aegypti en los seis cantones de la provincia de Limón. Los sitios de cría mas frecuentes fueron las llantas, los tarros o depósitos inservibles, los baldes y los tanques. Conclusiones: La proliferación del A. aegypti está directamente relacionado con el hombre, sus malos hábitos, y por la calidad de los servicios de salud de protección y mejoramiento del ambiente humano. Estos resultados demuestran que el abordaje del control del A. aegypti debe ser integral...

Dengue is the main disease due to vectorial transmission in Costa Rica. Its control requires comprehensive knowledge of its vector which uses a wide variety of artificial containers for breeding. Objectives: To identify and describe Aedes aegypti breeding sites present in the Limon province of Costa Rica. Materials and methods: this survey was carried out during the year 2011 by personnel of the Vector Control Program working simultaneously in six municipalities of the studied region. Results: We identified the presence of Aedes aegypti in six municipalities in the province of Limon. The most frequent breeding sites were tires, cans or unusable deposits, buckets and tanks. Conclusions: Proliferation of Aedes aegypti is directly related to man, his bad habits, and to the quality of health care models regarding protection and improvement of the human environment. These results show that the approach to control Aedes aegypti must be comprehensive...

Índices larvales de Aedes aegypti antes y después de intervenciones de control en Limón, Costa Rica / Larval indexes of Aedes aegypti before and after control intervention in Limón, Costa Rica

INTRODUCCIÓN: Costa Rica ha sufrido un incremento paulatino en la incidencia del dengue, con la presencia de algunos casos hemorrágicos. OBJETIVO: analizar el comportamiento de los índices entomológicos antes y después de intervenciones de control sobre el vector, así como identificar los sitios de cría de Aedes aegypti. MÉTODOS: se utilizó como fuente de información la base de datos de los trabajadores de vectores del Cantón de Limón en 15 localidades visitadas, antes y después de intervenciones sobre el vector durante septiembre-diciembre de 2007. Las intervenciones realizadas fueron: recogida de basura no convencional, destrucción de criaderos, uso de abate como larvicida y tratamiento térmico adulticida intradomiciliario y extradomiciliario. RESULTADOS: la primera encuesta mostró valores de índice casa por encima de 5 en 12 localidades, mientras que, 5 mostraron un aumento de sus valores después de las intervenciones durante la segunda encuesta. Se encontraron valores por encima de 30 por ciento pertenecientes a viviendas cerradas y renuentes a la visita. Los porcentajes de positividad en los terrenos baldíos fueron bajos, 3,6 y 2,9 por ciento antes y después de las intervenciones, respectivamente. Se reportaron 901 recipientes con larvas y pupas, los más positivos resultaron: diversos, tarros, estañones, llantas, baldes, cubetas y canoas. CONCLUSIÓN: la evaluación crítica de los resultados mostró un impacto significativo sobre los índices entomológicos después de las medidas de intervención, sin embargo, se recomienda para futuras intervenciones una revisión detallada del trabajo de terreno, para disminuir fallos en su implementación e incorporar nuevas medidas.

INTRODUCTION: Costa Rica has undergone a gradual increase of dengue incidence, including some hemorrhagic dengue cases. OBJECTIVE: to analyze the bahaviour of the entomological indexes before and after the control interventions on the vector as well as to identify the breeding sites of Aedes aegypti. METHODS: the source of information was the database from the vector control campaign workers in el Cantón de Limón in 15 visited locations, before and after the interventions from September through December 2007. The interventions comprised non-conventional garbage collection, destruction of breeding sites, use of abate as larvicide and heat treatment for adult vectors inside and outside the house. RESULTS: the first survey showed house-index values over 5 in 12 localities, whereas 5 exhibited increased values after the interventions during the second survey. Values exceeding 30 percent were found due to non-visited closed houses and to families that rejected to be visited. Positivity percentages in swampy places were low, 3,6 and 2,9 percent before and after the interventions, respectively. Nine hundred one reservoirs with larvae and pupas, being the most positive cans, jars, tyres, buckets and canoes. CONCLUSIONS: the critical assessment of the results showed a significant impact on the entomological indexes after the interventions; however, for future interventions, it was recommended to make a detailed review of the in situ work so as to reduce problems in the implementation and introduction of new measures.

Índices larvales de Aedes aegypti antes y después de intervenciones de control en Limón, Costa Rica / Larval indexes of Aedes aegypti before and after control intervention in Limón, Costa Rica

INTRODUCCIÓN: Costa Rica ha sufrido un incremento paulatino en la incidencia del dengue, con la presencia de algunos casos hemorrágicos. OBJETIVO: analizar el comportamiento de los índices entomológicos antes y después de intervenciones de control sobre el vector, así como identificar los sitios de cría de Aedes aegypti. MÉTODOS: se utilizó como fuente de información la base de datos de los trabajadores de vectores del Cantón de Limón en 15 localidades visitadas, antes y después de intervenciones sobre el vector durante septiembre-diciembre de 2007. Las intervenciones realizadas fueron: recogida de basura no convencional, destrucción de criaderos, uso de abate como larvicida y tratamiento térmico adulticida intradomiciliario y extradomiciliario. RESULTADOS: la primera encuesta mostró valores de índice casa por encima de 5 en 12 localidades, mientras que, 5 mostraron un aumento de sus valores después de las intervenciones durante la segunda encuesta. Se encontraron valores por encima de 30 por ciento pertenecientes a viviendas cerradas y renuentes a la visita. Los porcentajes de positividad en los terrenos baldíos fueron bajos, 3,6 y 2,9 por ciento antes y después de las intervenciones, respectivamente. Se reportaron 901 recipientes con larvas y pupas, los más positivos resultaron: diversos, tarros, estañones, llantas, baldes, cubetas y canoas. CONCLUSIÓN: la evaluación crítica de los resultados mostró un impacto significativo sobre los índices entomológicos después de las medidas de intervención, sin embargo, se recomienda para futuras intervenciones una revisión detallada del trabajo de terreno, para disminuir fallos en su implementación e incorporar nuevas medidas(AU)

INTRODUCTION: Costa Rica has undergone a gradual increase of dengue incidence, including some hemorrhagic dengue cases. OBJECTIVE: to analyze the bahaviour of the entomological indexes before and after the control interventions on the vector as well as to identify the breeding sites of Aedes aegypti. METHODS: the source of information was the database from the vector control campaign workers in el Cantón de Limón in 15 visited locations, before and after the interventions from September through December 2007. The interventions comprised non-conventional garbage collection, destruction of breeding sites, use of abate as larvicide and heat treatment for adult vectors inside and outside the house. RESULTS: the first survey showed house-index values over 5 in 12 localities, whereas 5 exhibited increased values after the interventions during the second survey. Values exceeding 30 percent were found due to non-visited closed houses and to families that rejected to be visited. Positivity percentages in swampy places were low, 3,6 and 2,9 percent before and after the interventions, respectively. Nine hundred one reservoirs with larvae and pupas, being the most positive cans, jars, tyres, buckets and canoes. CONCLUSIONS: the critical assessment of the results showed a significant impact on the entomological indexes after the interventions; however, for future interventions, it was recommended to make a detailed review of the in situ work so as to reduce problems in the implementation and introduction of new measures(AU)