ABSTRACT
RESUMEN Objetivo: Evaluar, bajo una perspectiva ecológica, la presencia de Aedes albopictus y su infección natural por virus dengue (DENV) en una zona de actividad piñera de Costa Rica. Método: Se colectaron mosquitos adultos en galerías forestales colindantes con piñeras, viviendas en proximidad a cultivos (<1 km) y viviendas en lejanía (110 km). Se empleó el índice de Shannon-Wiener para estimar biodiversidad. La infestación larvaria se evaluó en plantas de piña y viviendas y se calcularon índices aédicos de viviendas (IV) y de contenedores (IC). La detección de DENV en adultos (cuerpos y cabezas) y en larvas de Ae. albopictus se efectuó mediante RT-PCR y secuenciación. Resultados: Se colectaron 1376 adultos en total: Ae. albopictus (5,81%), Anopheles apicimacula (5,01%), Culex coronator (11,55%), Cx. inflictus (6,1%), Cx. nigripalpus (48,11%), Cx. quinquefasciatus (23,34%) y Limatus durhamii (0,07%). El índice de biodiversidad fue mayor en galerías forestales. Ae. albopictus adultos fueron colectados principalmente en el área de piñeras (73/80), aunque sólo dos larvas en las plantas de piña. Los índices aédicos en proximidad (IV: 40,7%, IC: 26,9%) y en lejanía (IV: 51,7%, IC: 29,6%) no mostraron diferencias significativas (IV Z=0,56, p=0,58; IC Z=0,16, p=0,87). Se detectó DENV-2 y DENV-3 en 2/20 grupos de cabezas y DENV-1 en 2/74 grupos de larvas de Ae. albopictus. Discusión: Las galerías forestales próximas a cultivos de piña podrían considerarse "islas ecológicas" adecuadas para el refugio de Ae. albopictus. La presencia de DENV en adultos y larvas sugiere un papel activo de Ae. albopictus en la transmisión de virus en este ecosistema.
ABSTRACT Objective To evaluate, under an ecological perspective, the presence of Aedes albopictus and the wild infection by dengue viruses (DENV) in an area of pineapple activity in Costa Rica. Materials and methods Adult mosquitoes were collected in forest galleries limiting pineapple plantations, houses adjacent to plantations (<1 km), and distant houses (1-10 km). Shannon-Wiener index was used to estimate biodiversity. Larval infestation was evaluated in pineapple plants and houses, and aedic house (HI) and container (CI) indices were calculated. Detection of DENV in Ae. albopictus adults (bodies and heads) and larvae was performed by RT-PCR and sequencing. Results A total 1376 adult mosquitoes were collected: Ae. albopictus (5.81%), Anopheles apicimacula (5.01%), Culex coronator (11.55%), Cx. inflictus (6.1%), Cx. nigripalpus (48.11%), Cx. quinquefasciatus (23.34%), and Limatus durhamii (0.07%). Biodiversity index was higher in forest galleries. Most adult Ae. albopictus were collected in forests close to pineapple fields (73/80), although only 2 larvae were detected in pineapple plants. Larval indices in adjacent houses (HI: 40.7%, CI: 26.9%) and distant houses (HI: 51.7%, CI: 29.6%) were similar (HI Z=0.56, p=0.58; CI Z=0.16, p=0.87). DENV-2 and DENV-3 were detected in 2/20 "pools" of Ae. albopictus heads and DENV-1 in 2/74 "pools" of larvae. Conclusion Forest galleries that are in proximity to pineapple plantations could be considered "ecological islands" that are suitable for refuge of Ae. albopictus. Presence of DENV in adults and larvae suggests an active role for Ae. albopictus in virus transmission within this ecosystem.
ABSTRACT
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.