Reducing costs and operational constraints of dengue vector control by targeting productive breeding places: a multi‐country non‐inferiority cluster randomized trial

Abstract

Summaryobjectives To test the non-inferiority hypothesis that a vector control approach targeting only the most productive water container types gives the same or greater reduction of the vector population as a non-targeted approach in different ecological settings and to analyse whether the targeted intervention is less costly.methods Cluster randomized trial in eight study sites (Venezuela, Mexico, Peru, Kenya, Thailand, Myanmar, Vietnam, Philippines), with each study area divided into 18-20 clusters (sectors or neighbourhoods) of approximately 50-100 households each. Using a baseline pupal-demographic survey, the most productive container types were identified which produced ‡55% of all Ae. aegypti pupae. Clusters were then paired based on similar pupae per person indices. One cluster from each pair was randomly allocated to receive the targeted vector control intervention; the other received the 'blanket' (nontargeted) intervention attempting to reach all water holding containers.results The pupal-demographic baseline survey showed a large variation of productive container types across all study sites. In four sites the vector control interventions in both study arms were insecticidal and in the other four sites, non-insecticidal (environmental management and ⁄ or biological control methods). Both approaches were associated with a reduction of outcome indicators in the targeted and non-targeted intervention arm of the six study sites where the follow up study was conducted (PPI, Pupae per Person Index and BI, Breteau Index). Targeted interventions were as effective as non-targeted ones in terms of PPI. The direct costs per house reached were lower in targeted intervention clusters than in non-targeted intervention clusters with only one exception, where the targeted intervention was delivered through staff-intensive social mobilization.conclusions Targeting only the most productive water container types (roughly half of all water holding container types) was as effective in lowering entomological indices as targeting all water holding containers at lower implementation costs. Further research is required to establish the most efficacious method or combination of methods for targeted dengue vector interventions.keywords dengue, vector control, targeted intervention, efficiency of interventions Tropical Medicine and International Health

Productividad de Aedes aegypti (L.) (Diptera: Culicidae) en viviendas y espacios públicos en una ciudad endémica para dengue en Colombia

“…b Es necesario tener en cuenta que en esta categoría solo se inspeccionó un recipiente. c Edificios gubernamentales (alcaldía, policía nacional, tránsito y transporte) sobre los índices por persona y por hectárea, junto con los datos sobre la contribución relativa de recipientes específicos (en viviendas de Girardot: albercas y tanques bajos; en el espacio público: tarros, vasijas, llantas y sumideros), respalda la implementación de estrategias que permitan una apropiada evaluación de su impacto, sin detrimento de la vigilancia entomológica que debe hacerse en otros recipientes, sobre todo en espacios públicos, con menor productividad del insecto que, debido a la presión del control, pueden volverse más productivos (14). Además, debe reconocerse que en cada conglomerado pueden expresarse aspectos sociales que determinan la fluctuación de los sitios de cría más aptos para el vector del dengue.…”

“…Esta aproximación permite establecer el índice de pupas por persona, es decir, la cantidad de pupas en las viviendas con respecto a su número de habitantes, y el índice de pupas por hectárea, con el que se determina la densidad del insecto en el área de un espacio público (10); con estos índices se pueden establecer las zonas con mayor riesgo potencial de transmisión del dengue (13). La estratificación espacio-temporal de la productividad del vector del dengue, permite focalizar y evaluar estrategias de prevención y control para conseguir un uso más eficiente de los recursos (14).…”

Aedes aegypti entomological indices in an endemic area for dengue in Sao Paulo State, Brazil

“…1, 2,4,6,14,16,18,25 The best candidates for productive container types for pupae are canvases, car parts, drums and tires, which were found at low frequencies among the inspected containers and had levels of pupa productivity well above those frequencies. However, these four container types (11.6% of those inspected) accounted for 40.6% of pupa productivity, which is insuffi cient to ensure the success of the vector control program if the elimination and/or treatment strategies focused only on these containers.…”

La dengue, maladie complexe

“…À la recherche de gîtes de ponte en eau, de préférence claire, les indices larvaires sont élevés dans un périmètre restreint autour des maisons (Harrington et al, 2005). Ces relations d'influence de l'environnement sur le moustique motivent alors les stratégies de gestion de l'environnement : destructions ciblées en milieux domiciliaires (Tun-Lin et al, 2009), fumigation des espaces publics (OMS, 2012a) ou encore aménagements des espaces urbains (Gubler, 2011).…”