Refuges are also provided by the piled bricks laid on mud beside the hen. Most refuges are provided by abundant deep cracks in the mud (with straw) wall below the shelf where the hen lays. A: Detail of a ‘nidero’ (elevated shelf for chickens to nest) against a mud wall, rated 5. The scale of refuge availability ranges from 1 (no refuge at all) to 5 (abundant suitable refuges). A more integrated perspective that considers simultaneously social, economic and biological processes at local and regional scales is needed to attain effective, sustainable vector and disease control.įigure S1: Model examples of degrees of refuge availability for Triatoma infestans in Pampa del Indio. Fewer refuges are likely to result in fewer residual foci after insecticide spraying, and will facilitate community-based vector surveillance. Ethnic background (Creole or Toba) adjusted for other factors showed little or no association.Conclusions/significancePromotion and effective implementation of housing improvement (including key peridomestic structures) combined with appropriate insecticide use and host management practices are needed to eliminate infestations. Availability of refuges for bugs, construction with tarred cardboard, and host abundance (humans, dogs, cats, and poultry) per site were positively associated with infestation and abundance, whereas reported insecticide use showed a negative association. A multi-model inference approach using Akaike's information criterion was applied to assess the relative importance of each variable by running all possible (17,406) models resulting from all combinations of variables.
Domiciles with mud walls and roofs of thatch or corrugated tarred cardboard were more often infested (32.2%) than domiciles with brick-and-cement walls and corrugated metal-sheet roofs (15.1%). The most frequently infested ecotopes were domiciles, kitchens, storerooms, chicken coops and nests corrals were rarely infested. Infested sites were significantly aggregated at distances of 0.8-2.5 km. We conducted a cross-sectional study to model factors affecting bug presence and abundance at sites within house compounds in a well-defined rural area in the humid Argentine Chaco.Methodology/principal findingsTriatoma infestans bugs were found in 45.9% of 327 inhabited house compounds but only in 7.4% of the 2,584 sites inspected systematically on these compounds, even though the last insecticide spraying campaign was conducted 12 years before. BackgroundTransmission of Trypanosoma cruzi by Triatoma infestans remains a major public health problem in the Gran Chaco ecoregion, where understanding of the determinants of house infestation is limited.
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