Distribution of triatomine species in domestic and peridomestic environments in central coastal Ecuador

Abstract

BackgroundAlthough the central coast of the Ecuador is considered endemic for Chagas disease, few studies have focused on determining the risk of transmission in this region. In this study we describe the triatomine household infestation in Manabí province (Central Coast region), determine the rate of Trypanosoma cruzi infection and study the risk factors associated with infestation by Rhodnius ecuadoriensis.Methodology/Principal findingsAn entomological survey found three triatomine species (Rhodnius ecuadoriensis, Panstrongylus rufotuberculatus and P. howardi) infesting domiciles in 47.4% of the 78 communities visited (total infestation rate of 4.5%). Four percent of domiciles were infested, and nymphs were observed in 77% of those domiciles. The three species were found in altitudes below 500 masl and in all ecological zones except cloud forest. Within the domicile, we found the three species mostly in bedrooms. Rhodnius ecuadoriensis and P. rufotuberculatus were abundant in bird nests, including chicken coops and P. howardi associated with rats in piles of bricks, in the peridomicile. Triatomine infestation was characterized by high rates of colonization, especially in peridomicile. Flagelates infection was detected in only 12% of the samples by microscopy and Trypanosoma cruzi infection in 42% of the examined triatomines by PCR (n = 372). The most important risk factors for house infestation by R. ecuadoriensis were ecological zone (w = 0.99) and presence of chickens (w = 0.96). Determinants of secondary importance were reporting no insecticide applications over the last twelve months (w = 0.86) and dirt floor (w = 0.70). On the other hand, wood as wall material was a protective factor (w = 0.85).Conclusion/SignificanceAccording the results, approximately 571,000 people would be at high risk for T. cruzi infection in Manabí province. A multidisciplinary approximation and the adhesion to a periodic integrated vector management (IVM) program are essential to guarantee sustainable preventive and control strategies for Chagas disease in this region.

Determinants of intentions to prevent triatomine infestation based on the health belief model: An application in rural southern Ecuador

“…These root causes are in part behavioral. Practices in the communities make homes conducive to triatomine infestation, including the accumulation of materials in the home, such as extra clothing or building supplies, which creates hiding places for triatomines during the day, and the accumulation of foodstuffs that attract rodents and small animals that can act as hosts for triatomines [14][15][16]. Animal husbandry practices, such as keeping chicken nests against the walls of the home, keeping Guinea pigs in the house or allowing pigs and goats to move from the wild to the peridomicile to the home [15], attract triatomines.…”

Under pressure: phenotypic divergence and convergence associated with microhabitat adaptations in Triatominae

“…aequatorialis palms of Manabí and houses of northwestern Peru (department of Cajamarca, Mashcon-Marañón basin) were supplied by J Jurberg (LNIRTT) (S1 Table). We conducted a detailed review of external morphological and chromatic characters central to classical triatomine-bug taxonomy [1,41], and placed the results in the broader context of what we know about the systematics, biogeography, and ecology of R. ecuadoriensis [1,2,8,18,[25][26][27][28][29][30][31][32][33][34][35][36]38,39]. In particular, we emphasize that northern populations exploit palm-crown microhabitats just like most Rhodnius species do [2,29], whereas wild southern-Andean populations are associated with vertebrate tree-nests in dry ecoregions where palms are either rare or absent [2,8,[25][26][27][28][29][30][31][32][33][34].…”

“…The natural habitats of Peruvian populations remain largely unknown, with a few records suggesting association with vertebrate nests/refuges in hollow trees and perhaps cacti [2,26,27,34]. In addition, some R. ecuadoriensis populations have adapted to live in and around houses in coastal Ecuador and, especially, in the dry valleys of southwestern Ecuador and northwestern Peru -where the bugs contribute to endemic Chagas disease [24][25][26][35][36][37][38][39]. Our comparative phenotypic and genetic analyses reveal that phenotypic divergence and convergence can both occur within a single nominal triatomine-bug species, and suggest that microhabitat adaptations likely play a crucial role in this phenomenon.…”

Modelling geospatial distributions of the triatomine vectors of Trypanosoma cruzi in Latin America

“…Here we use a target-group background (TGB) approach by choosing 67 background data that exhibits similar sampling bias as the occurrence data [31]. This 68 approach can reduce the bias introduced by preferential sampling of the presence 69 locations. It was successfully used to map geographical distributions of malaria hosts 70 and vectors [32] and predict infection risk zones of yellow fever [33].…”

“…There are locally important species for which maps could not be produced because they 273 are only found within areas where the relevant surveillance records are not publicly 274 available or because their range is limited so only small numbers of observations exist. 275 For example, Rhodnius ecuadoriensis is an important vector in Ecuador [69] but the 276 databases used in this study only provided 11 and 23 records, respectively, for known 277 collection dates after the year 2000.…”