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We used sentinel animal enclosures to measure the rate of infestation by the Chagas disease vector, Triatoma infestans, in an urban community of Arequipa, Peru, and to evaluate the effect of deltamethrin-impregnated netting on that rate. Impregnated netting decreased the rate of infestation of sentinel enclosures (rate ratio, 0.23; 95% confidence interval, 0.13–0.38; P < 0.001), controlling for the density of surrounding vector populations and the distance of these to the sentinel enclosures. Most migrant insects were early-stage nymphs, which are less likely to carry the parasitic agent of Chagas disease, Trypanosoma cruzi. Spread of the vector in the city therefore likely precedes spread of the parasite. Netting was particularly effective against adult insects and late-stage nymphs; taking into account population structure, netting decreased the reproductive value of migrant populations from 443.6 to 40.5. Impregnated netting can slow the spread of T. infestans and is a potentially valuable tool in the control of Chagas disease.
Received March 11, 2008. Accepted for publication June 30, 2008.
Acknowledgments: We thank the community of Nueva Alborada for participation and hospitality during this study. We especially thank Rocio Rodriguez, Amparo Toledo, and the sprayers and field collectors who worked on the study. We also thank Gregory Martin, Jeffrey Stancil, David Bentzel, Ellen Dotson, Lucy Rubio, Gena Lawrence, Linda Webb, Karina Oppe, and Fernando Malaga for assistance and support. The authors thank Torben Frandsen for fabrication and donation of the guinea pig PermaNets.
Financial support: This study received financial support from the UNICEF/UNDP/World Bank/WHO Special Program for Research and Training in Tropical Diseases (TDR Grant A50684). M.Z.L. was supported by a Howard Hughes Pre-doctoral fellowship. V.Q.M., J.L.Y.V., K.B., and B.R. were supported by a training grant from the Fogarty Center of the NIH. Additional support came from National Institutes of Health Grants U19-AI-33061 and RO1-AI047498.
* Address correspondence to Michael Z. Levy, Fogarty International Center, 31 Center Drive, MSC2220, Bethesda, MD 20892-2220. E-mail: levymz{at}yahoo.com
Authors addresses: Michael Levy and F. Ellis McKenzie, Fogarty International Center, National Institutes of Health, MSC2220, Bethesda, MD 20892-2220. Victor R. Quíspe-Machaca, Jose L. Ylla-Velasquez, Jean M. Richards, Bruno Rath, and Katty Borrini-Mayori, Asociacio ' n Bene 'fica Proyectos en Informa 'tica, Salud, Me-dicina y Agricultura (AB PRISMA), 251 Carlos Gonzales, Maranga, San Miguel, Lima 32, Peru. Lance Waller, Department of Biostatistics, 1518 Clifton Rd., NE, Rollins School of Public Health, Emory University, Atlanta, GA 30322. Juan Cornejo del Carpio, Dirección Regional del Ministerio de Salud, Av. Daniel Alcides Carrión 505, Arequipa, Peru. Eleazar Cordova-Benzaquen, Universidad Nacional San Agustín, Facultad de Medicina, Arequipa, Peru. Robert A. Wirtz and Caryn Bern, Division of Parasitic Diseases, Centers for Disease Control and Prevention, Mailstop F-22, Atlanta, GA 30341. James H. Maguire, Division of Infectious Disease, Brigham and Womens Hospital, PBBA-475 Francis Street, Boston, MA 02115. Robert H. Gil-man, Department of International Health, Bloomberg School of Public Health, 615 N. Wolfe St. rm W5515, Baltimore, MD 21205.
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