The genetic structure of Aedes aegypti populations is driven by boat traffic in the Peruvian Amazon

• Type of Material: Article
• Authors: Sarah AnneJ. Guagliardo, Emory University; Yoosook Lee, University of California, Davis; Amanda A. Pierce, Emory University; Jacklyn Wong, University of California, Davis; Yui Yin Chu, University of California, Davis; Amy C. Morrison, University of California, Davis; Helvio Astete, Iquitos Laboratory; Berry Brosi, Emory University; Gonzalo Vazquez Prokopec, Emory University; Thomas W. Scott, University of California, Davis; Uriel Kitron, Emory University; Steven T. Stoddard, University of California, Davis
• Language: English
• Date: 2019-09-01
• 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.0007552
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 13
• Issue: 9
• Start Page: e0007552
• End Page: e0007552
• Grant/Funding Information: Additional support was provided by the US National Institutes of Health-National Institute of Allergy and Infectious Diseases (NIH/NIAID) grants R01 AI069341-01 and P01 AI098670 (TW Scott, PI); and by the Research and Policy for Infectious Disease Dynamics (RAPIDD) program of the Science and Technology Directory; Department of Homeland Security; and Fogarty International Center, National Institutes of Health.; This study was supported 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.
• Research Categories: Biology, Entomology; Environmental Sciences

Abstract

In the Americas, as in much of the rest of the world, the dengue virus vector Aedes aegypti is found in close association with human habitations, often leading to high population densities of mosquitoes in urban settings. In the Peruvian Amazon, this vector has been expanding to rural communities over the last 10-15 years, but to date, the population genetic structure of Ae. aegypti in this region has not been characterized. To investigate the relationship between Ae. aegypti gene flow and human transportation networks, we characterized mosquito population structure using a panel of 8 microsatellite markers and linked results to various potential mechanisms for long-distance dispersal. Adult and immature Ae. aegypti (>20 individuals per site) were collected from Iquitos city and from six neighboring riverine communities, i.e., Nauta, Indiana, Mazan, Barrio Florida, Tamshiaco, and Aucayo. FST statistics indicate significant, but low to moderate differentiation for the majority of study site pairs. Population structure of Ae. aegypti is not correlated with the geographic distance between towns, suggesting that human transportation networks provide a reasonable explanation for the high levels of population mixing. Our results indicate that Ae. aegypti gene flow among sub-populations is greatest between locations with heavy boat traffic, such as Iquitos-Tamshiaco and Iquitos-Indiana-Mazan, and lowest between locations with little or no boat/road traffic between them such as Barrio Florida-Iquitos. Bayesian clustering analysis showed ancestral admixture among three genetic clusters; no single cluster was exclusive to any site. Our results are consistent with the hypothesis that human transportation networks, particularly riverways, are responsible for the geographic spread of Ae. aegypti in the Peruvian Amazon. Our findings are applicable to other regions of the world characterized by networks of urban islands connected by fluvial transport routes.