Field Efficacy of Larvivorous Fish and Pyriproxyfen Combined with Community Engagement on Dengue Vectors in Cambodia: A Randomized Controlled Trial

View More View Less
  • 1 Epidemiology Department, Malaria Consortium, Phnom Penh, Cambodia;
  • | 2 MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, United Kingdom;
  • | 3 Department of Vector Control, Cambodian National Dengue Control Program, Phnom Penh, Cambodia;
  • | 4 Department of Climate Change and Health, World Health Organization, Phnom Penh, Cambodia;
  • | 5 Department of Entomology, US Naval Medical Research Unit-2, Phnom Penh, Cambodia

Evidence on the effectiveness of low-cost, sustainable biological vector control tools for Aedes mosquitoes is limited. Therefore, the purpose of this trial was to estimate the impact of guppy fish in combination with the larvicide pyriproxyfen (PPF) (Sumilarv® 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 or more villages each was allocated in a 1:1:1 ratio to receive either 1) all three interventions (guppies, PPF, and COMBI), 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 rates was aggregated over follow-up time points to give a single rate per cluster. These data were analyzed by negative binomial regression, yielding abundance ratios (ARs). The number of Aedes females was reduced roughly by half compared with the control in both the guppy, PPF, and COMBI arm (AR = 0.54; 95% CI, 0.34–0.85; P = 0.0073); and the guppy and COMBI arm (AR = 0.49; 95% CI, 0.31–0.77; P = 0.0021). The effectiveness demonstrated and extremely low cost of including fish rearing in community-based health structures suggest they should be considered as a vector control tool as long as the benefits outweigh any potential environmental concerns. Sumilarv® 2MR was also highly accepted and preferred over current vector control tools used in Cambodia.

Author Notes

Address correspondence to John Christian Hustedt, Epidemiology Department, Malaria Consortium, #5, St. 282, BKK1, Phnom Penh, Cambodia. E-mail: john.hustedt@alumni.lshtm.ac.uk

Financial support: This project was co-funded by the U.K. Agency for International Development (UKAID) (40097745) and the Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) (81181153). UKAID funded project activities until March 2016; GIZ funded activities until November 2016. N. A. and J. B. receive support from the UK Medical Research Council (MRC) UK and Department for International Development (DFID)–MRC (grant reference MR/R010161/1). This award is funded jointly by the UK MRC and the UK DFID under the MRC–DFID Concordat agreement and is also part of the EDCTP2 Programme supported by the European Union. The funders had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Authors’ addresses: John Christian Hustedt, Epidemiology Department, Malaria Consortium, Phnom Penh, Cambodia, and MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK, E-mail: john.hustedt@alumni.lshtm.ac.uk. Dyna Doum, Vanney Keo, Muhammad Shafique, Sergio Lopes, and Jeffrey Hii, Epidemiology Department, Malaria Consortium, Phnom Penh, Cambodia, E-mails: dynadoum@gmail.com, vanneykeo@gmail.com, muhammad.shafique2002@gmail.com, sergiooolopes@gmail.com, and hiijk1@gmail.com. Sokha Ly, BunLeng Sam, and Leang Rithea, Department of Vector Control, Cambodian National Dengue Control Program, Phnom Penh, Cambodia, E-mails: lysokha@yahoo.com, sambunleng@gmail.com, and rithealeang@gmail.com. Vibol Chan, Department of Climate Change and Health, World Health Organization, Phnom Penh, Cambodia, E-mail: chanv@who.int. Neal Alexander, John Bradley, and Marco Liverani, MRC Tropical Epidemiology Group, Department of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK, E-mails: neal.alexander@lshtm.ac.uk, john.bradley@lshtm.ac.uk, and marco.liverani@lshtm.ac.uk. Didot Budi Prasetyo and Agus Rachmat, Department of Entomology, US Naval Medical Research Unit-2, Phnom Penh, Cambodia, E-mails: didot.prasetyo.ctr@namru2.org.kh and agus.rachmat.ctr@namru2.org.kh.

Save