Key Source Habitats and Potential Dispersal of Triatoma infestans Populations in Northwestern Argentina: Implications for Vector Control

• Type of Material: Article
• Authors: Ricardo E. Gürtler, Universidad de Buenos Aires; María C. Cecere, Universidad de Buenos Aires; María del Pilar Fernández, Universidad de Buenos Aires; Gonzalo Vazquez Prokopec, Emory University; Leonardo A. Ceballos, Universidad de Buenos Aires; Juan M. Gurevitz, Universidad de Buenos Aires; Uriel Kitron, Emory University; Joel E. Cohen, Columbia University
• Language: English
• Date: 2014-10-09
• Publisher: Public Library of Science
• Publication Version: Final Published Version
• Copyright Statement: © 2014 Gürtler et al.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1371/journal.pntd.0003238
• Title of Journal or Parent Work: PLoS Neglected Tropical Diseases
• ISSN: 1935-2727
• Volume: 8
• Issue: 10
• Start Page: e3238
• End Page: e3238
• Grant/Funding Information: This study was supported by awards from the National Institutes of Health/National Science Foundation Ecology of Infectious Disease program award R01TW05836 funded by the Fogarty International Center and the National Institute of Environmental Health Sciences to UK, REG and JEC, Agencia Nacional de Promoción Científica y Tecnológica (PICT and PICTO-Glaxo), and the University of Buenos Aires to REG.; JEC acknowledges with thanks the support of U.S. National Science Foundation grants EF-1038337 and DMS-1225529.; REG and MCC are members of CONICET Researcher's Career.
• Keywords: Infectious disease control; Female; Insect flight; Fecundity; Flight (biology); Insect Control; Humans; Ecosystem; Feeding Behavior; Swine; Seasons; Goats; Animals; Demography; Rural Population; Triatoma; Chickens; Residence Characteristics; Insecticides; Chagas Disease; Argentina
• Research Categories: Health Sciences, Epidemiology; Environmental Sciences

Abstract

Background: Triatoma infestans —the principal vector of the infection that causes Chagas disease— defies elimination efforts in the Gran Chaco region. This study identifies the types of human-made or -used structures that are key sources of these bugs in the initial stages of house reinfestation after an insecticide spraying campaign. Methodology and Principal Findings: We measured demographic and blood-feeding parameters at two geographic scales in 11 rural communities in Figueroa, northwest Argentina. Of 1,297 sites searched in spring, 279 (21.5%) were infested. Bug abundance per site and female fecundity differed significantly among habitat types (ecotopes) and were highly aggregated. Domiciles (human sleeping quarters) had maximum infestation prevalence (38.7%), human-feeding bugs and total egg production, with submaximal values for other demographic and blood-feeding attributes. Taken collectively peridomestic sites were three times more often infested than domiciles. Chicken coops had greater bug abundance, blood-feeding rates, engorgement status, and female fecundity than pig and goat corrals. The host-feeding patterns were spatially structured yet there was strong evidence of active dispersal of late-stage bugs between ecotopes. Two flight indices predicted that female fliers were more likely to originate from kitchens and domiciles, rejecting our initial hypothesis that goat and pig corrals would dominate. Conclusions and Significance: Chicken coops and domiciles were key source habitats fueling rapid house reinfestation. Focusing control efforts on ecotopes with human-fed bugs (domiciles, storerooms, goat corrals) would neither eliminate the substantial contributions to bug population growth from kitchens, chicken coops, and pig corrals nor stop dispersal of adult female bugs from kitchens. Rather, comprehensive control of the linked network of ecotopes is required to prevent feeding on humans, bug population growth, and bug dispersal simultaneously. Our study illustrates a demographic approach that may be applied to other regions and triatomine species for the design of innovative, improved vector control strategies.