Prevalence, Genetic Characterization, and 18S Small Subunit Ribosomal RNA Diversity of <i>Trypanosoma rangeli</i>in Triatomine and Mammal Hosts in Endemic Areas for Chagas Disease in Ecuador

Ocaña-Mayorga, Sofía; Aguirre-VillacisFernanda,; Miguel, PintoC.; Vallejo, Gustavo Adolfo; Grijalva, Mario J.

doi:10.1089/vbz.2015.1794

Cited by 19 publications

(16 citation statements)

References 59 publications

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“…It is interesting to note that the infection rate with T. cruzi was lower (41.3%) than that reported for R. pallescens collected from others endemic areas in Panama [ 8 , 22 ]. However, the rate found for the infection with T. rangeli is one of the highest reported in Panama and other regions where this parasite has been described [ 9 , 23 – 25 ]. These high infection frequencies with T. rangeli seem to be inconsistent with the described pathological effects of T. rangeli for its vectors [ 26 ].…”

Section: Resultsmentioning

confidence: 99%

A darker chromatic variation of Rhodnius pallescens infected by specific genetic groups of Trypanosoma rangeli and Trypanosoma cruzi from Panama

et al. 2018

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BackgroundRhodnius pallescens, the only species of this genus reported in Panama, has a wide geographical distribution and is associated with most cases of Chagas disease and human infections with Trypanosoma rangeli in this country. Thus far, no phenotypic variants of this triatomine have been registered. Similarly, genotyping of the trypanosomes that infect this vector has only been partially evaluated.ResultsA total of 347 specimens of R. pallescens were collected in Attalea butyracea palm trees located near a mountainous community of the district of Santa Fe, province of Veraguas. Bugs were slightly longer and had a darker coloration compared to that reported for this species. Infection rates for trypanosomes performed with three PCR analyses showed that 41.3% of the adult triatomines were positive for T. cruzi, 52.4% were positive for T. rangeli and 28.6% had mixed T. cruzi/T. rangeli infections. Based on cox2 analysis, TcI was the single T. cruzi discrete typing unit (DTU) detected, and a genetic variant of KP1(-)/lineage C was the only genetic group found for T. rangeli.ConclusionsA darker chromatic variation of R. pallescens predominates in a mountainous region of Panama. These triatomines show high trypanosome infection rates, especially with T. rangeli. Regarding T. rangeli genetic diversity, complementary studies using other molecular markers are necessary to better define its phylogenetic position.

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Section: Resultsmentioning

confidence: 99%

A darker chromatic variation of Rhodnius pallescens infected by specific genetic groups of Trypanosoma rangeli and Trypanosoma cruzi from Panama

et al. 2018

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“…Association of this parasite with Rhodnius spp. is well known [34,35,36,37]] while the presence of T . rangeli in the genus Panstrongylus might be the result of temporary infections and do not imply transmission of T .…”

Section: Discussionmentioning

confidence: 99%

“…rangeli in the genus Panstrongylus might be the result of temporary infections and do not imply transmission of T . rangeli by this species [37]. It is important to note that only intestinal content was analyzed and not salivary glands, so the infection rate of T .…”

Section: Discussionmentioning

confidence: 99%

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

et al. 2017

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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.

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“…Intestinal contents from captured triatomines were isolated for detection of trypanosomes. Detection was carried through PCR amplification of the conserved domain of minicircle of kinetoplast DNA (kDNA), as described in [ 6 , 38 ]. The differential detection of T. cruzi and T. rangeli was based on the size of the PCR products.…”

Section: Methodsmentioning

confidence: 99%

Influence of ecological factors on the presence of a triatomine species associated with the arboreal habitat of a host of Trypanosoma cruzi

et al. 2018

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BackgroundThe white-naped squirrel, Simosciurus nebouxii (previously known as Sciurus stramineus), has recently been identified as an important natural host for Trypanosoma cruzi in Ecuador. The nests of this species have been reported as having high infestation rates with the triatomine vector Rhodnius ecuadoriensis. The present study aims to determine the levels of nest infestation with R. ecuadoriensis, the ecological variables that are influencing the nest site selection, and the relationship between R. ecuadoriensis infestation and trypanosome infection.ResultsThe study was carried out in transects in forest patches near two rural communities in southern Ecuador. We recorded ecological information of the trees that harbored squirrel nests and the trees within a 10 m radius. Manual examinations of each nest determined infestation with triatomines. We recorded 498 trees (n = 52 with nests and n = 446 without nests). Rhodnius ecuadoriensis was present in 59.5% of the nests and 60% presented infestation with nymphs (colonization). Moreover, we detected T. cruzi in 46% of the triatomines analyzed.ConclusionsWe observed that tree height influences nest site selection, which is consistent with previous observations of squirrel species. Factors such as the diameter at breast height and the interaction between tree height and tree species were not sufficient to explain squirrel nest presence or absence. However, the nest occupancy and tree richness around the nest were significant predictors of the abundance of triatomines. Nevertheless, the variables of colonization and infection were not significant, and the data observed could be expected because of chance alone (under the null hypothesis). This study ratifies the hypothesis that the ecological features of the forest patches around rural communities in southern Ecuador favor the presence of nesting areas for S. nebouxii and an increase of the chances of having triatomines that maintain T. cruzi populations circulating in areas near human dwellings. Additionally, these results highlight the importance of including ecological studies to understand the dynamics of T. cruzi transmission due to the existence of similar ecological and land use features along the distribution of the dry forest of southern Ecuador and northern Peru, which implies similar challenges for Chagas disease control.Electronic supplementary materialThe online version of this article (10.1186/s13071-018-3138-4) contains supplementary material, which is available to authorized users.

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Prevalence, Genetic Characterization, and 18S Small Subunit Ribosomal RNA Diversity of Trypanosoma rangeliin Triatomine and Mammal Hosts in Endemic Areas for Chagas Disease in Ecuador

Cited by 19 publications

References 59 publications

A darker chromatic variation of Rhodnius pallescens infected by specific genetic groups of Trypanosoma rangeli and Trypanosoma cruzi from Panama

A darker chromatic variation of Rhodnius pallescens infected by specific genetic groups of Trypanosoma rangeli and Trypanosoma cruzi from Panama

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

Influence of ecological factors on the presence of a triatomine species associated with the arboreal habitat of a host of Trypanosoma cruzi

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