Research needs for Chagas disease prevention.

We present an overview of the two main strategies for the primary (vector control) and secondary (patient care) prevention of Chagas disease (CD). We identify major advances, knowledge gaps, and key research needs in both areas. Improved specific chemotherapy, including more practical formulations (e.g., paediatric) or combinations of existing drugs, and a better understanding of pathogenesis, including the relative weights of parasite and host genetic makeup, are clearly needed. Regarding CD vectors, we find that only about 10-20% of published papers on triatomines deal directly with disease control. We pinpoint the pitfalls of the current consensus on triatomine systematics, particularly within the Triatomini, and suggest how some straightforward sampling and analytical strategies would improve research on vector ecology, naturally leading to sounder control-surveillance schemes. We conclude that sustained research on CD prevention is still crucial. In the past, it provided not only the know-how, but also the critical mass of scientists needed to foster and consolidate CD prevention programmes; in the future, both patient care and long-term vector control would nonetheless benefit from more sharply focused, problem-oriented research

The ecology and genetics of Chagas disease vectors in Ecuador, with emphasis on Rhodnius ecuadoriensis (Hemiptera: Reduviidae: Triatominae)

An estimate >11 million people are infected by Trypanosoma cruzi in Latin America. Chagas disease control programmes have been successful in the Southern Cone countries, and similar initiatives are underway in the Andean countries. In Ecuador prevalence is estimated as ~ 130000 people, with 2.5-3.8 million at risk; annual associated costs may reach >20 million US dollars. We studied ecological, genetic, and evolutionary aspects of Rhodnius ecuadoriensis, an important disease vector in western Ecuador and northwestern Peru. Sylvatic and synanthropic populations are sympatric in central Ecuador; only domestic-peridomestic colonies occur in the temperate Andean valleys of southern Ecuador and northern Peru. Both morphological-chromatic features and ecological-behavioural preferences seem to define a cline [sylvatic-large (north) - synanthropic-small (south)]. The ecology of domestic and sylvatic populations was studied using logistic regression. Phytelephas aequatorialis palms are the primary natural ecotope of R ecuadoriensis; sylvatic bugs tend to favour male palms with large amounts of decomposing organic material and located in cropland/pasture fields. Poor households with mud walls, tiled roofs and large numbers of chickens were more likely to be infested. Isometry-free morphometric analysis consistently achieved >90% correct discrimination of sylvatic vs. synanthropic populations, supporting the use of metric variables in surveillance of reinfestations; size-free analyses revealed substantial divergence of Peruvian bugs from La Libertad. Mitochondrial DNA sequence polymorphisms (cytochrome b gene, 663 basepairs) were analysed; ~4% sequence divergence scored between Ecuadorian and Peruvian populations suggested they are independent phylogroups. Haplotype diversity and relationships indicate central coastal Ecuador as the centre of dispersal of this species, with isolated domestic populations in dry Andean valleys. The phylogeny of this species was explored using morphometric and molecular approaches. The monophyly of the `Pacific Rhodnius lineage' (pallescens, colombiensis and ecuadoriensis) was confirmed, with the parapatric pallescens and colombiensis being very closely related; R. pictipes is the closest relative to this lineage among Amazonian species, with the robustus group forming a distinct, major Glade. Control of R ecuadoriensis can contemplate local eradication in dry Andean valleys (southern Ecuador and northern Peru); special attention should be paid to peridomestic populations, including improvement of poultry management (burning-replacing nests every 15-30 days). Long-term interruption of disease transmission would benefit from educational interventions increasing awareness about Chagas disease and from housing improvements targeting mud walls and timber-and-tile roofs. In central-northern western Ecuador peridomestic palm trees may be the origin of reinfestations; environmental management (removing dead fronds and fibres from peridomestic palms), and continuous community- based surveillance are recommended. A comprehensive control programme over 15 years would probably result in interruption of disease transmission, and could bring savings of about 20 US$ per each dollar invested.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

A catalogue of reusable context model elements based on the i* framework

The definition of the context of a system is one of the most relevant activities in the early phases of information systems engineering. It allows system engineers to narrow the system scope, by defining well established system boundaries. In practice, outlining a system context model is complex and cumbersome. In order to support context modeling, in this paper we propose a catalogue of context model elements expressed in i*, which can be reused as building blocks in the construction of context models for new systems. We describe the process used for the identification of a set of actors and dependencies recurrently appearing in several academic and industrial cases, and the process to store them into a catalogue of reusable i* context dependencies.Peer ReviewedPostprint (author's final draft

i* in practice: identifying frequent problems in its application

Several notations have been proposed in the last decades to support information system architecting, design and implementation. Although some of them have been widely adopted, their practical application remains cumbersome. Reasons are manifold: ambiguous semantics, confusing graphical representation, lack of safe guidelines, etc. In this paper, we explored the use of the i* framework in industry for modeling organizational context. We review the models resulting from 36 industrial collaborations conducted in the last five years, where i* has been intensively used by novice modellers, without previous exposure to i*, acting as junior consultants in the organizations. We identify and categorize the main problems that they faced and as a result, we propose a set of guidelines to improve the adoption and practical application of the framework.Peer ReviewedPostprint (author's final draft

MORPHOMETRIC DISTINCTION OF DOMESTIC AND SYLVATIC POPULATIONS OF Rhodnius ecuadoriensis FROM DIFFERENT GEOGRAPHICAL ORIGINS

ABSTRACTRhodnius ecuadoriensis (Hemiptera, Reduviidae) is an important vector of both Trypanosoma hemoflagellates, Trypanosoma cruzi and Trypanosoma rangeli, in Ecuador and Peru. Ecotopes of sylvatic and domestic/peridomestic habitats have been reported in Ecuador. Meanwhile in Peru, to the best of our knowledge, findings of sylvatic populations in their different ecosystem regions have not yet been documented. Could this be the product of a lack of appropriate studies on wild populations of triatominae in Peruvian environments? In order to elucidate this topic, we take advantage of new insights in geometric morphometry as a tool to help differentiate between wild populations and the corresponding domestic/peridomestic ones, collected in their respective environments. When analyzing our results, we confirmed the efficacy of this technique in our study, and furthermore, we believe that it could be a proper tool for rangeliosis and Chagas disease vector control surveillance in Ecuador and Peru.Keywords: Morphometric geometry, sylvatic, domestic/peridomiestic populations distinction, Rhodnius ecuadoriensis. RESUMENRhodnius ecuadoriensis (Hemiptera, Reduviidae) es un importante vector de los tripanosomas Trypanosoma cruzi y Trypanosoma rangeli en el Ecuador y Perú. Se han reportado ecotopos de hábitats silvestres y domésticos/peridomésticos en Ecuador. Sin embargo, en Perú, hasta donde sabemos, no se ha documentado hallazgos de dichas poblaciones silvestres. ¿Podría este ser el caso de una falta de estudios focalizados en la búsqueda de poblaciones silvestres de triatominos dentro de los diferentes ecosistemas del Perú? Para elucidar este tema, aplicamos nuevas perspectivas en morfometría geométrica, como una herramienta que podría auxiliar en la diferenciación de poblaciones silvestres de aquellas domésticas/peridomésticas, colectadas en sus respectivos ambientes naturales. Al analizar nuestros resultados, se confirmó la utilidad de esta técnica dentro de nuestro estudio, y esto nos llevó a creer asimismo que serviría como un elemento apropiado en el control vectorial de la enfermedad de Chagas y de la rangeliosis, en Ecuador y Perú.Palabras claves: Geometría morfométrica, silvestre, diferenciación de poblaciones domesticas/peridomesticas, Rhodnius ecuadoriensis

Community Participation in Chagas Disease Vector Surveillance: Systematic Review

Blood-sucking triatomine bugs are the vectors of Chagas disease, a potentially fatal illness that affects millions in Latin America. With no vaccines available, prevention heavily depends on controlling household-infesting triatomines. Insecticide-spraying campaigns have effectively reduced incidence, but persistent household reinfestation can result in disease re-emergence. What, then, is the best strategy to keep houses free of triatomines and thus interrupt disease transmission in the long run? We reviewed published evidence to (i) assess the effectiveness of insecticide-based vector control, gauging the importance of reinfestation; (ii) compare the efficacy of programme-based (with households periodically visited by trained staff) and community-based (with residents reporting suspect vectors found in their homes) surveillance strategies; and (iii) evaluate the performance of alternative vector-detection methods. The results confirm that insecticide-based vector control is highly effective, but also that persistent house reinfestation is a general trend across Latin America. Surveillance systems are significantly more effective when householders report suspect bugs than when programme staff search houses, either manually or using vector-detection devices. Our results clearly support the view that long-term vector surveillance will be necessary for sustained Chagas disease control – and that community participation can substantially contribute to this aim

Chagas disease control-surveillance in the americas: The multinational initiatives and the practical impossibility of interrupting vector-borne trypanosoma cruzi transmission

Chagas disease (CD) still imposes a heavy burden on most Latin American countries. Vector-borne and mother-to-child transmission cause several thousand new infections per year, and at least 5 million people carry Trypanosoma cruzi. Access to diagnosis and medical care, however, is far from universal. Starting in the 1990s, CD-endemic countries and the Pan American Health Organization-World Health Organization (PAHO-WHO) launched a series of multinational initiatives for CD control-surveillance. An overview of the initiatives’ aims, achievements, and challenges reveals some key common themes that we discuss here in the context of the WHO 2030 goals for CD. Transmission of T. cruzi via blood transfusion and organ transplantation is effectively under control. T. cruzi, however, is a zoonotic pathogen with 100+ vector species widely spread across the Americas; interrupting vector-borne transmission seems therefore unfeasible. Stronger surveillance systems are, and will continue to be, needed to monitor and control CD. Prevention of vertical transmission demands boosting current efforts to screen pregnant and childbearing-aged women. Finally, integral patient care is a critical unmet need in most countries. The decades-long experience of the initiatives, in sum, hints at the practical impossibility of interrupting vector-borne T. cruzi transmission in the Americas. The concept of disease control seems to provide a more realistic description of what can in effect be achieved by 2030.Fil: Rojas de Arias, Antonieta. Centro para el Desarrollo de la Investigación Científica; ParaguayFil: Monroy, Carlota. Universidad de San Carlos de Guatemala (univ. de San C. de Guatemala);Fil: Guhl, Felipe. Universidad de los Andes; ColombiaFil: Sosa-Estani, Sergio Alejandro. Drugs For Neglected Diseases Initiative; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Santos, Walter Souza. Ministério da Saúde; BrasilFil: Abad Franch, Fernando. Universidade do Brasília; Brasi

Supporting i*-based context models construction through the DHARMA ontology

The construction of enterprise context models, fundamental tool to design of modern information systems, is usually a cumbersome task to lead, largely due to the gap of communication between the administrative staff and technical consultants in charge of its construction. In order to make this task easier previous works encouraging the reuse of i* context elements through the implementation and use of catalogs has been proposed. In this paper, we make use of semantic technologies to exploit such catalog, storing its content in a semantic repository. To support this idea, we have created the DHARMA ontology following the guidelines proposed by NeOn methodology, integrating different domains and their vocabularies.Peer ReviewedPostprint (published version