Sofia Ocaña-Mayorga

Sofia Ocaña-Mayorga
Pontificia Universidad Católica del Ecuador | PUCE · Center of Research on Health in Latin America

PhD in Biological Sciences

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24
Publications
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604
Citations

Publications

Publications (24)
Article
Chagas disease is endemic in ~70% of Ecuador. Rhodnius ecuadoriensis and Triatoma carrioni (Hemiptera: Reduviidae) are the primary vectors of Chagas disease in Southern Ecuador. This study tested the effectiveness of selective deltamethrin application of Domiciliary Units (DUs) infested with triatomines, coupled with community education activities...
Article
Full-text available
Accurate prediction of vectors dispersal, as well as identification of adaptations that allow blood-feeding vectors to thrive in built environments, are a basis for effective disease control. Here we adopted a landscape genomics approach to assay gene flow, possible local adaptation, and drivers of population structure in Rhodnius ecuadoriensis , a...
Article
Transmission risk of Chagas disease has been associated with human-vector contacts and triatomines colonizing dwellings, but alternative scenarios, independent of domestic colonization, are poorly documented. In the present work, we estimated the frequency of human blood meals in triatomines from domicile, peridomicile, and sylvatic environments in...
Article
Full-text available
Trypanosoma cruzi, a zoonotic kinetoplastid protozoan parasite, is the causative agent of American trypanosomiasis (Chagas disease). Having a very plastic, repetitive and complex genome, the parasite displays a highly diverse repertoire of surface molecules, with pivotal roles in cell invasion, immune evasion and pathogenesis. Before 2016, the comp...
Article
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Understanding the blood meal patterns of insects that are vectors of diseases is fundamental in unveiling transmission dynamics and developing strategies to impede or decrease human–vector contact. Chagas disease has a complex transmission cycle that implies interactions between vectors, parasites and vertebrate hosts. In Ecuador, limited data on h...
Article
Full-text available
Analysis of genetic polymorphism is a powerful tool for epidemiological surveillance and research. Powerful inference from pathogen genetic variation, however, is often restrained by limited access to representative target DNA, especially in the study of obligate parasitic species for which ex vivo culture is resource-intensive or bias-prone. Moder...
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Background: Understanding local anopheline vector species and their bionomic traits, as well as related human factors, can help combat gaps in protection. Methods: In San José de Chamanga, Esmeraldas, at the Ecuadorian Pacific coast, anopheline mosquitoes were sampled by both human landing collections (HLCs) and indoor-resting aspirations (IAs)...
Preprint
Full-text available
Analysis of genetic polymorphism is a powerful tool for epidemiological surveillance and research. Powerful inference from pathogen genetic variation, however, is often restrained by limited access to representative target DNA, especially in the study of obligate parasitic species for which ex vivo culture is resource-intensive or bias-prone. Moder...
Article
Full-text available
Abstract Background: The 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 a...
Preprint
Full-text available
Trypanosoma cruzi , a zoonotic kinetoplastid protozoan with a complex genome, is the causative agent of American trypanosomiasis (Chagas disease). The parasite uses a highly diverse repertoire of surface molecules, with roles in cell invasion, immune evasion and pathogenesis. Thus far, the genomic regions containing these genes have been impossible...
Article
Full-text available
Background: Although 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 ri...
Article
Full-text available
Background: Rhodnius ecuadoriensis is the main triatomine vector of Chagas disease, American trypanosomiasis, in Southern Ecuador and Northern Peru. Genomic approaches and next generation sequencing technologies have become powerful tools for investigating population diversity and structure which is a key consideration for vector control. Here we...
Article
Substantial heterogeneity exists in the dispersal, distribution and transmission of parasitic species. Understanding and predicting how such features are governed by the ecological variation of landscape they inhabit is the central goal of spatial epidemiology. Genetic data can further inform functional connectivity among parasite, host and vector...
Article
Full-text available
Trypanosoma rangeli is a nonpathogenic parasite for humans; however, its medical importance relies in its similarity and overlapping distribution with Trypanosoma cruzi, causal agent of Chagas disease in the Americas. The genetic diversity of T. rangeli and its association with host species (triatomines and mammals) has been identified along Centra...
Article
Full-text available
The generalist parasite Trypanosoma cruzi has two phylogenetic lineages associated almost exclusively with bats—Trypanosoma cruzi Tcbat and the subspecies T. c. marinkel-lei. We present new information on the genetic variation, geographic distribution, host associations , and potential vectors of these lineages. We conducted field surveys of bats a...
Article
Full-text available
Background: Chagas disease is endemic to the southern Andean region of Ecuador, an area with one of the highest poverty rates in the country. However, few studies have looked into the epidemiology, vectors and transmission risks in this region. In this study we describe the triatomine household infestation in Loja province, determine the rate of T...
Article
Full-text available
Chagas disease is the most important parasitic disease in Latin America. The causative agent, Trypanosoma cruzi, displays high genetic diversity and circulates in complex transmission cycles among domestic, peridomestic and sylvatic environments. In Ecuador, Rhodnius ecuadoriensis is known to be the major vector species implicated in T. cruzi trans...
Article
Full-text available
The elimination of domestic triatomines is the foundation of Chagas disease control. Regional initiatives are eliminating introduced triatomine species. In this scenario, endemic triatomines can occupy the ecological niches left open and become a threat to long-term Chagas disease control efforts. This study determined the abundance, colonization,...
Article
Full-text available
Chagas disease transmission risk is a function of the presence of triatomines in domestic habitats. Rhodnius ecuadoriensis is one of the main vectors implicated in transmission of Trypanosoma cruzi in Ecuador. This triatomine species is present in domestic, peridomestic and sylvatic habitats in the country. To determine the distribution of sylvatic...
Article
Full-text available
This year-long study evaluated the effectiveness of a strategy involving selective deltamethrin spraying and community education for control of Chagas disease vectors in domestic units located in rural communities of coastal Ecuador. Surveys for triatomines revealed peridomestic infestation with Rhodnius ecuadoriensis and Panstrongylus howardi, wit...
Article
Full-text available
Molecular epidemiology at the community level has an important guiding role in zoonotic disease control programmes where genetic markers are suitably variable to unravel the dynamics of local transmission. We evaluated the molecular diversity of Trypanosoma cruzi, the etiological agent of Chagas disease, in southern Ecuador (Loja Province). This ki...
Article
Full-text available
We performed a cross-sectional study of Trypanosoma cruzi seroprevalence in 14 communities in three provinces of Ecuador and estimated the magnitude of the association of seropositive individuals within households. A total of 3,286 subjects from 997 households were included. Seroprevalence was 5.7%, 1.0%, and 3.6% in subjects in the Manabí, Guayas,...
Article
Full-text available
Few studies on the relationship between environmental factors and Trypanosoma cruzi transmission have been conducted in Ecuador. We conducted a cross-sectional study of household risk factors for T. cruzi seropositivity in 2 distinct geographical regions of Ecuador. Exposure information was collected via household surveys, and subjects were tested...
Article
Full-text available
Small mammals trapped in domestic and peridomestic environments of rural Ecuador were screened for trypanosome infection by direct microscopy and hemoculture. Identification of species of trypanosomes was then performed by morphological characteristics and by polymerase chain reaction (PCR) assays. Of 194 animals collected, 15 were positive for inf...

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