Factors Affecting Infestation by Triatoma infestans in a Rural Area of the Humid Chaco in Argentina: A Multi-Model Inference Approach

Abstract

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. 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 Findings Triatoma 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. Infested sites were significantly aggregated at distances of 0.8–2.5 km. The most frequently infested ecotopes were domiciles, kitchens, storerooms, chicken coops and nests; corrals were rarely infested. 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%). 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. 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. 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. Fewer refuges are likely to result in fewer residual foci after insecticide spraying, and will facilitate community-based vector surveillance. 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.

An rK28-Based Immunoenzymatic Assay for the Diagnosis of Canine Visceral Leishmaniasis in Latin America

“…These included groups of (A) healthy dogs (N = 80) and (B) ill dogs (N = 41), affected by infectious and other diseases including distemper, brucellosis, bacterial infections, and noninfectious pathologies as neoplasm, anemias, renal failure, urolithiasis, Cushing syndrome, heart disease, vestibular syndrome, prolapsed organs, and inflammatory diseases; group 2: Trypanosoma cruzi-infected dogs (N = 108) from rural areas of Santiago del Estero and Chaco, both endemic Argentinean provinces for Chagas disease, which were diagnosed using two or three serological tests. 19,20 Group 3 corresponds to T. cruzi-noninfected dogs living in Chaco (N = 71) in the same area as those dogs mentioned in group 2.…”

New Sylvatic Hosts of Trypanosoma cruzi and Their Reservoir Competence in the Humid Chaco of Argentina: A Longitudinal Study

“…Field work was conducted in a well-defined rural area (450 km 2 ) in the municipality of Pampa del Indio (25 55 S, 56 58 W), Chaco Province, Argentina, which has been described elsewhere. 26 For present purposes, the study area included six neighboring villages (Santa Rita, Santos Lugares, El Salvaje, La Loma, Campo Los Toros, and Los Ciervos). The area is in the dry sub-humid region.…”

Transmission and Epidemiology of Zoonotic Protozoal Diseases of Companion Animals

“…Specific risk factors for CD in areas of endemicity based on large-scale seroprevalence and triatome surveillance surveys were the presence of the vector, nearby cropland and grassland, disarray of the domiciliary environment, and mud and thatch or tarred cardboard homes and outbuildings (190)(191)(192). Other factors, including evidence of triatome infestation of the home and the presence of a companion animal sharing a room with an individual, were significantly associated with CD in Peru (193).…”