River Boats Contribute to the Regional Spread of the Dengue Vector Aedes aegypti in the Peruvian Amazon

• Type of Material: Article
• Authors: Sarah Anne Guagliardo, Emory University; Amy C. Morrison, University of California Davis; Jose Luis Barboza, Universidad Nacional de la Amazonía Peruana; Edwin Requena, Universidad Nacional de la Amazonía Peruana; Helvio Astete, U. S. Naval Medical Research Unit No.6 (NAMRU-6) Iquitos Laboratory; Gonzalo Vazquez Prokopec, Emory University; Uriel Kitron, Emory University
• Language: English
• Date: 2015-04-10
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: This is an open access article, free of all copyright, and may be freely reproduced, distributed, transmitted, modified, built upon, or otherwise used by anyone for any lawful purpose.
• License: Creative Commons Creative Commons CC0 1.0 Universal
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pntd.0003648
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 9
• Issue: 4
• Start Page: e0003648
• End Page: e0003648
• Grant/Funding Information: Funding for this study was provided by the National Institutes of Health Training Grant in the Population Biology of Infectious Diseases No. T32 AI55404-10 (L Real, PI) and by the Achievement Rewards for College Students (ARCS) Global Health Impact Award. Logistical support for this study was also provided by NIH/NIAID award No. R01 AI069341-01 (TW Scott, PI).
• Keywords: Larvae; Boats; Mosquitoes; Rivers; Adults; Pupae; Transportation; Aedes aegypti
• Research Categories: Health Sciences, Public Health; Environmental Sciences

Abstract

Background and Objectives The dramatic range expansion of the dengue vector Aedes aegypti is associated with various anthropogenic transport activities, but little is known about the underlying mechanisms driving this geographic expansion. We longitudinally characterized infestation of different vehicle types (cars, boats, etc.) to estimate the frequency and intensity of mosquito introductions into novel locations (propagule pressure). Methods Exhaustive adult and immature Ae. aegypti collections were performed on six different vehicle types at five ports and two bus/ taxi departure points in the Amazonian city of Iquitos, Peru during 2013. Aquatic vehicles included 32 large and 33 medium-sized barges, 53 water taxis, and 41 speed boats. Terrestrial vehicles sampled included 40 buses and 30 taxis traveling on the only highway in the region. Ae. aegypti adult infestation rates and immature indices were analyzed by vehicle type, location within vehicles, and sampling date. Results Large barges (71.9% infested) and medium barges (39.4% infested) accounted for most of the infestations. Notably, buses had an overall infestation rate of 12.5%. On large barges, the greatest number of Ae. aegypti adults were found in October, whereas most immatures were found in February followed by October. The vast majority of larvae (85.9%) and pupae (76.7%) collected in large barges were produced in puddles formed in cargo holds. Conclusions Because larges barges provide suitable mosquito habitats (due to dark, damp cargo storage spaces and ample oviposition sites), we conclude that they likely serve as significant contributors to mosquitoes’ propagule pressure across long distances throughout the Peruvian Amazon. This information can help anticipate vector population mixing and future range expansions of dengue and other viruses transmitted by Ae. aegypti.