Effect of an intervention in storm drains to prevent Aedes aegypti reproduction in Salvador, Brazil

• Type of Material: Article
• Authors: Raquel Lima Souza, Instituto Gonçalo Moniz; Vánio André Mugabe, Instituto Gonçalo Moniz; Igor Adolfo Dexheimer Paploski, Instituto Gonçalo Moniz; Moreno S. Rodrigues, Instituto Gonçalo Moniz; Patricia Sousa Dos Santos Moreira, Instituto Gonçalo Moniz; Leile Camila Jacob Nascimento, Instituto Gonçalo Moniz; Christopher Michael Roundy, University of Texas Medical Branch; Scott C. Weaver, University of Texas Medical Branch; Mitermayer Galvão Reis, Instituto Gonçalo Moniz; Uriel Kitron, Emory University; Guilherme Sousa Ribeiro, Instituto Gonçalo Moniz
• Language: English
• Date: 2017-07-11
• Publisher: BioMed Central
• Publication Version: Final Published Version
• Copyright Statement: © 2017 BioMed Central Ltd unless otherwise stated. Part of Springer Nature.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1186/s13071-017-2266-6
• Title of Journal or Parent Work: Parasites and Vectors
• ISSN: 1756-3305
• Volume: 10
• Issue: 1
• Grant/Funding Information: This study was supported by the Brazilian National Council for Scientific and Technological Development (grants 400830/2013-2 and 440891/2016-7 to GSR, and scholarships to IADP, MSR, VAM, UK, MGR and GSR), the Brazilian Coordination for the Improvement of Higher Education (grant 440891/2016-7 to GSR), and the UTMB’s Institute for Human Infections and Immunity (pilot grant to CR and SW).
• Keywords: Storm drain; Mosquitoes; Entomology; Disease vectors; Catch basin; Aedes aegypti; Epidemiology; Arboviruses; Insect vectors
• Research Categories: Biology, Microbiology; Health Sciences, Immunology; Environmental Sciences

Abstract

Background: Aedes aegypti, the principal vector for dengue, chikungunya and Zika viruses, is a synanthropic species that uses stagnant water to complete its reproductive cycle. In urban settings, rainfall water draining structures, such as storm drains, may retain water and serve as a larval development site for Aedes spp. reproduction. Herein, we describe the effect of a community-based intervention on preventing standing water accumulation in storm drains and their consequent infestation by adult and immature Ae. aegypti and other mosquitoes. Methods: Between April and May of 2016, local residents association of Salvador, Brazil, after being informed of water accumulation and Ae. aegypti infestation in the storm drains in their area, performed an intervention on 52 storm drains. The intervention consisted of placing concrete at the bottom of the storm drains to elevate their base to the level of the outflow tube, avoiding water accumulation, and placement of a metal mesh covering the outflow tube to avoid its clogging with debris. To determine the impact of the intervention, we compared the frequency at which the 52 storm drains contained water, as well as adult and immature mosquitoes using data from two surveys performed before and two surveys performed after the intervention. Results: During the pre-intervention period, water accumulated in 48 (92.3%) of the storm drains, and immature Ae. aegypti were found in 11 (21.2%) and adults in 10 (19.2%). After the intervention, water accumulated in 5 (9.6%) of the storm drains (P < 0.001), none (0.0%) had immatures (P < 0.001), and 3 (5.8%) contained adults (P = 0.039). The total number of Ae. aegypti immatures collected decreased from 109 to 0 (P < 0.001) and adults decreased from 37 to 8 (P = 0.011) after the intervention. Collection of immature and adult non-Aedes mosquitoes (mainly Culex spp.) in the storm drains also decreased after the intervention. Conclusion: This study exemplifies how a simple intervention targeting storm drains can result in a major reduction of water retention, and, consequently, impact Ae. aegypti larval populations. Larger and multi-center evaluations are needed to confirm the potential of citywide structural modifications of storm drains to reduce Aedes spp. infestation level.