Field efficacy of larvivorous fish and pyriproxyfen combined with community engagement on dengue vectors in cambodia: A randomized controlled trial

Abstract

Evidence on the effectiveness of low-cost, sustainable biological vector control tools for Aedesmosquitoes is limited. Therefore, the purpose of this trial was to estimate the impact of guppy fish in combination with the larvicide pyriproxyfen (PPF) (SumilarvVR 2MR) and communication for behavioral impact (COMBI) activities to reduce entomological indices in Cambodia. In this cluster randomized, controlled superiority trial, 30 clusters comprised of one ormore villages each was allocated in a 1:1:1 ratio to receive either 1) all three interventions (guppies, PPF, andCOMBI), 2) two interventions (guppies and COMBI), or 3) control (standard vector control). Entomological surveys among 40 randomly selected households per cluster were carried out quarterly. The primary outcome was the population abundance of adult female Aedes mosquitoes trapped using adult resting collections. In the primary analysis, adult female Aedes abundance and mosquito infection rateswas aggregatedover follow-up time points to give a single rateper cluster.Thesedatawere analyzed by negative binomial regression, yielding abundance ratios (ARs). The number ofAedes femaleswas reduced roughly by half comparedwith the control in both the guppy,PPF, andCOMBI arm(AR50.54; 95%CI, 0.34-0.85; P50.0073); and the guppy andCOMBI arm(AR5 0.49; 95%CI, 0.31-0.77; P5 0.0021). The effectiveness demonstrated and extremely low cost of including fish rearingin community-basedhealth structures suggest they should be considered as a vector control tool as long as the benefits outweigh any potential environmental concerns. SumilarvVR 2MR was also highly accepted and preferred over current vector control tools used in Cambodia.