Anita G Villacis

Pontificia Universidad Católica del Ecuador | PUCE · Escuela de Ciencias Biológicas

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...

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...

Background: Panstrongylus rufotuberculatus (Hemiptera-Reduviidae) is a triatomine species with a wide geographic distribution and a broad phenotypic variability. In some countries, this species is found infesting and colonising domiciliary ecotopes representing an epidemiological risk factor as a vector of Trypanosoma cruzi, etiological agent of C...

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...

The biology of vector adaptation to the human habitat remains poorly understood for many arthropod-borne diseases but underpins effective and sustainable disease control. We adopted a landscape genomics approach to investigate gene flow, signatures of local adaptation, and drivers of population structure among multiple linked wild and domestic popu...

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...

Chagas disease (CD) is caused by Trypanosoma cruzi and transmitted by the feces of Triatomine insects. The absence of treatments and effective vaccines makes this disease not only a medical problem, but also an educational, social and psychological problem. Education appears as an important axis of research for the prevention of this disease. For t...

Background: Chagas disease is a parasitic infection transmitted by "kissing bugs" (Hemiptera: Reduviidae: Triatominae) that has a huge economic impact in Latin American countries. The vector species with the upmost epidemiological importance in Ecuador are Rhodnius ecuadoriensis (Lent & Leon, 1958) and Triatoma dimidiata (Latreille, 1811). However...

Rhodnius ecuadoriensis is one of the most important vector species of Chagas disease in Ecuador. This species is distributed in the Central coast region and in the south Andean region, and an incipient speciation process between these geographical populations was previously proposed. The current population genetics study only focused on the Central...

Introduction Control of triatomine infestation is a key strategy for the prevention of Chagas disease (CD). To promote this strategy, it is important to know which antecedents to behavioral change are the best to emphasize when promoting prevention. Objective The aim of this study was to determine predictors for intention to prevent home infestati...

Limited genetic data are currently available for three vectors of Chagas disease in Ecuador, Panstrongylus howardi, P. chinai, and P. rufotuberculatus. Previously regarded as mainly sylvatic, these species have been poorly studied. Recently, they have been more frequently reported in domiciles and peridomiciles and are now considered true secondary...

Chagas disease is caused by Trypanosoma cruzi (Kinetoplastida: Trypanosomatidae). It is transmitted to humans primarily through contaminated feces of blood-sucking vectors of the subfamily Triatominae, known in Ecuador as ‘chinchorros’. Some Triatominae species can adapt to domiciliary and peridomiciliary environments where T. cruzi can be transmit...

Dentro de la biología que estudia los procesos de vida desde un punto de vista molecular, nos hemos interesado particularmente en las secuencias de la macromolécula de ácido desoxirribonucleico abreviado como ADN, la cual es de gran utilidad para comprender quiénes son los triatominos, vectores de la enfermedad de Chagas.

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...

BACKGROUND: Eggs have epidemiological and taxonomic importance in the subfamily Triatominae, which contains Chagas disease vectors. The metric properties (size and shape) of eggs are useful for distinguishing between close species, or different geographical populations of the same species. METHODS: We examined the effects of egg viability on its m...

Vector transmission remains the main mode of Chagas disease transmission. The first part of this chapter presents the current state of knowledge on the transmission mechanisms, the factors that attract bugs to their prey, how bug saliva helps feeding, and several milestones to understand how the parasite invades a wide variety of vertebrate cells....

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...

Entomological indices and altitude range of triatomine infestation in rural communities of Manabí province, 2009–2011 (37 infested communities). (DOCX)

Publically available database. (ZIP)

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...

Reagents and 2b-RAD protocol used in this study. (PDF)

Results of the best fit model selection for each Type IIB-REase dataset. (PDF)

Detailed information of R. ecuadoriensis samples used in this study. (PDF)

Nonlinear least squares (NLS) analysis. (PDF)

Effective control of Chagas disease vector populations requires a good understanding of the epidemiological components, including a reliable analysis of the genetic structure of vector populations. Rhodnius ecuadoriensis is the most widespread vector of Chagas disease in Ecuador, occupying domestic, peridomestic and sylvatic habitats. It is widely...

To distinguish species or populations using morphometric data is generally processed through multivariate analyses, in particular the discriminant analysis. We explored another approach based on the maximum likelihood method. Simple statistics based on the assumption of normal distribution at a single variable allows to compute the chance of observ...

Background Egg morphometrics in the Triatominae has proved to be informative for distinguishing tribes or genera, and has been based generally on traditional morphometrics. However, more resolution is required, allowing species or even population recognition, because the presence of eggs in the domicile could be related to the species ability to co...

The taxonomic knowledge about Triatominae subfamily, in which we find the vectors of Chagas disease, was mainly focused in the study of adults and nymphs, and the information about the egg stages has been very limited. We present a geometric approach comparing eggs of three epidemiologically important Ecuadorian species (Panstrongylus chinai, P. ho...

Chagas disease is caused by the protozoan Trypanosoma cruzi Panstrongylus chinai (Del Ponte) is highly domiciliated in the Peruvian and Ecuadorian Andes and has been found naturally infected with T. cruzi The objective of this study was to describe the life cycle, feeding, and defecation patterns of P. chinai in the Loja province within southern Ec...

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...

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...

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...

Chagas disease, or American Tripanosomiasis, is a disease caused by Trypanosoma cruzi, the causative agent (PAHO, 2006). T. cruzi is transmitted by blood-sucking vectors of the subfamily Triatominae, in Ecuador they are known by the name of "chinchorros". These triatomine go through five nymphal stages before becoming adults, but from the first nym...

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,...

Chagas disease (ChD) is caused by the protozoan Trypanosoma cruzi. Panstrongylus chinai is one of the main vectors of ChD that has been found naturally infected with T. cruzi. This species has been reported inhabiting synanthropic environments (domestic and peridomestic). The adaptation of triatomines to different habitats including a series of mor...

Triatoma virus (TrV) is a small, non-enveloped virus that has a þssRNA genome and is currently classified under the Cripavirus genus of the Dicistroviridae family. TrV infects haematophagous triatomine insects (Hemiptera: Reduviidae), which are vectors of American trypanosomosis (Chagas disease). TrV can be transmitted through the horizontal faecal...

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...

Effective control of Chagas Disease requires a good understanding of the epidemiological cycles, including a reliable analysis of the genetic structure of vector populations. Rhodnius ecuadoriensis, the most widespread vector of this disease in Ecuador, occupies domestic, peridomestic and sylvatic habitats and is a widely distributed species in the...

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...

Rhodnius ecuadoriensis is an important vector of Chagas disease in Ecuador. Whereas only sylvatic and peridomestic populations are common in Manabi province, this species occupies domestic, peridomestic, and sylvatic habitats in Loja province where high reinfestation of houses was observed. To explore the existence of phenetic changes linked to the...

Rhodnius ecuadoriensis is considered the second most important vector of Chagas disease in Ecuador. It is distributed across six of the 24 provinces and occupies intradomiciliary, peridomiciliary and sylvatic habitats. This study was conducted in six communities within the coastal province of Guayas. Triatomine searches were conducted in domestic a...

Chagas disease is a serious public health problem in Ecuador, where nearly 230,000 individuals show Trypanosoma cruzi infection. Sylvatic T. cruzi transmission is a threat to current control strategies. This is because of the possibility of house reinfestation by sylvatic triatomines after insecticide treatment. This work quantified the spatial dis...

The main vectors of Chagas disease in Ecuador are Triatoma dimidiata and Rhodnius ecuadoriensis. The latter species occupies domestic and peridomestic habitats, as well as sylvatic ecotopes--particularly associated with Phytelephas aequatorialis palm trees--in the western coastal region of Ecuador. In the southern highlands, however, such palm tree...

Chagas Disease (ChD) constitutes a serious health problem in Latin America and in Ecuador. Rhodnius ecuadoriensis is considered one the main vectors of ChD in this country. Populations of R. ecuadoriensis are widely distributed in the central Coastal region (Manabí province) and southern Highland region (Loja province) of Ecuador, where they occupy...

Rhodnius ecuadoriensis is the second most important vector of Chagas Disease (CD) in Ecuador. The objective of this study was to describe (and compare) the life cycle, the feeding and defecation patterns under laboratory conditions of two populations of this specie [from the provinces of Manabí (Coastal region) and Loja (Andean region)]. Egg-to-adu...