title: Dynamics of sylvatic Chagas disease vectors in coastal Ecuador is driven by changes in land cover.
abstract: BACKGROUND
  Chagas disease is a serious public health problem in Latin America where about ten million individuals show Trypanosoma cruzi infection. Despite significant success in controlling domiciliated triatomines, sylvatic populations frequently infest houses after insecticide treatment which hampers long term control prospects in vast geographical areas where vectorial transmission is endemic. As a key issue, the spatio-temporal dynamics of sylvatic populations is likely influenced by landscape yet evidence showing this effect is rare. The aim of this work is to examine the role of land cover changes in sylvatic triatomine ecology, based on an exhaustive field survey of pathogens, vectors, hosts, and microhabitat characteristics' dynamics.
  
  
  RESULTS
  The study was performed in agricultural landscapes of coastal Ecuador as a study model. Over one year, a spatially-randomized sampling design (490 collection points) allowed quantifying triatomine densities in natural, cultivated and domestic habitats. We also assessed infection of the bugs with trypanosomes, documented their microhabitats and potential hosts, and recorded changes in landscape characteristics. In total we collected 886 individuals, mainly represented by nymphal stages of one triatomine species Rhodnius ecuadoriensis. As main results, we found that 1) sylvatic triatomines had very high T. cruzi infection rates (71%) and 2) densities of T. cruzi-infected sylvatic triatomines varied predictably over time due to changes in land cover and occurrence of associated rodent hosts.
  
  
  CONCLUSIONS
  We propose a framework for identifying the factors affecting the yearly distribution of sylvatic T. cruzi vectors. Beyond providing key basic information for the control of human habitat colonization by sylvatic vector populations, our framework highlights the importance of both environmental and sociological factors in shaping the spatio-temporal population dynamics of triatomines. A better understanding of the dynamics of such socio-ecological systems is a crucial, yet poorly considered, issue for the long-term control of Chagas disease.
authors: Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Tropical Disease Institute, Department of Biomedical Sciences, Heritage College of Osteopathic Medicine, Ohio University, Athens, Ohio, United States of America.
authors: Mario J
authors: MJ
authors: Grijalva
authors: Center for Infectious Disease Research, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador.
authors: David
authors: D
authors: Terán
authors: Laboratory of Entomology, School of Biological Sciences, Pontifical Catholic University of Ecuador, Quito, Ecuador; Institut de Recherche pour le Développement (IRD), UR 072, Laboratoire Evolution, Génomes et Spéciation, UPR 9034, Centre National de la Recherche Scientifique (CNRS), Gif sur Yvette, France et Université Paris-Sud 11, Orsay, France; Instituto de Ecología, Universidad Mayor San Andrés, Cotacota, La Paz, Bolivia.
authors: Olivier
authors: O
authors: Dangles
mesh_terms: D000383:Agriculture / Q000379:methods; D000818:Animals; D014355:Chagas Disease / Q000453:epidemiology*; D018556:Crops, Agricultural; D017753:Ecosystem; D004484:Ecuador / Q000453:epidemiology; D065928:Forests; D006798:Housing; D007303:Insect Vectors; D016014:Linear Models; D011156:Population Density; D011157:Population Dynamics; D012239:Rhodnius / Q000469:parasitology*; D012377:Rodentia; D012621:Seasons; D062211:Spatio-Temporal Analysis; D014349:Trypanosoma cruzi / Q000302:isolation & purification*