Risk factors for intradomiciliary infestation by the Chagas disease vector Triatoma dimidiata in Jutiapa, Guatemala

Seventeen variables were evaluated as possible risk factors for the intradomiciliary infestation with Triatoma dimidiata in 644 houses in Jutiapa, Guatemala. During 2004 the houses were assessed for vector presence and evaluated for hygiene, cluttering, material comfort, construction conditions and number of inhabitants, among other factors. Chi-square analysis detected significant associations between vector presence and eight variables related to domestic sanitary and construction conditions. Log-linear models showed that regardless of the age of the house, the odds of vector presence were 4.3 and 10 times lower in houses with a good socioeconomic status compared with poor and very poor houses respectively. Log-linear models also pointed to a greater chance of vector presence when walls lacked plastering (3.85 times) or walls had low quality-incomplete plastering (4.56 times), compared with walls that were completely plastered. Control strategies against T. dimidiata should include the introduction of better-quality but inexpensive plastering formulations and better sanitation practices should also be promoted among the population. Such control strategies should not only reduce or eliminate infestation, but also prevent vector reinfestation

Investigación multidisciplinaria e intersectorial en salud: Desarrollo de una nueva forma de control de los vectores de la enfermedad de Chagas

Biólogos, entomólogos, microbiológos, ingenieros, arquitectos, antropólogos y líderes comunitarios trabajan juntos para desarrollar una técnica para el control de los insectos vectores de la enfermedad de Chagas. La nueva estrategia de control está basada en modular los factores de riesgo, a través de remodelar y mejorar las viviendas de adobe o bajareque para que sean refractarias a las chinches; la remodelación incluye mejora de paredes y piso imitación cemento para que los insectos no se reproduzca dentro de la vivienda. Se usan materiales locales como cenizas volcánicas (selecto, puzolana), arena de rio, cal y una mínima cantidad de cemento. Después de capacitación, los mismos habitantes ejecutan las mejoras. Varias instituciones como las Municipalidades, el Ministerio de Salud, las Comunidades y la Universidad trabajan coordinadamente. Se han mejorado 7,000 viviendas de adobe y bajareque en Centro América y México. La evaluación de la efectividad para el control de Chagas es a través de presencia o ausencia de vectores, su distribución y la alimentación sanguínea de los insectos vectores. Se comprobó que disminuyeron las chinches, que estás se alimentan menos de humanos y que tiene la tendencia a quedarse fuera de la vivienda, lo que disminuye el contacto humano-vector. Esta alternativa de control a largo plazo es más económica que la forma tradicional de rociamiento con insecticidas

Ecohealth interventions limit triatomine reinfestation following insecticide spraying in La Brea, Guatemala

In this study, we evaluate the effect of participatory Ecohealth interventions on domestic reinfestation of the Chagas disease vector Triatoma dimidiata after village-wide suppression of the vector population using a residual insecticide. The study was conducted in the rural community of La Brea, Guatemala between 2002 and 2009 where vector infestation was analyzed within a spatial data framework based on entomological and socio-economic surveys of homesteads within the village. Participatory interventions focused on community awareness and low-cost home improvements using local materials to limit areas of refuge and alternative blood meals for the vector within the home, and potential shelter for the vector outside the home. As a result, domestic infestation was maintained at ≤ 3% and peridomestic infestation at ≤ 2% for 5 years beyond the last insecticide spraying, in sharp contrast to the rapid reinfestation experienced in earlier insecticide only interventions. Copyright © 2013 by The American Society of Tropical Medicine and Hygiene

Description of Triatoma huehuetenanguensis sp. n., a potential Chagas disease vector (Hemiptera, Reduviidae, Triatominae)

A new species of the genus Triatoma Laporte, 1832 (Hemiptera, Reduviidae) is described based on specimens collected in the department of Huehuetenango, Guatemala. Triatoma huehuetenanguensis sp. n. is closely related to T. dimidiata (Latreille, 1811), with the following main morphological differences: lighter color; smaller overall size, including head length; and width and length of the pronotum. Natural Trypanosoma cruzi (Chagas, 1909) infection, coupled with its presence in domestic habitats, makes this species a potentially important vector of Trypanosoma cruzi in Guatemala

Distribución de Aedes albopictus (Diptera: Culicidad) en Guatemala, seguimiento a una colonización de 1995

En Guatemala se descubrieron poblaciones establecidas de Aedes albopictus (Sukuse) por primera vez en 1995 en la región del Caribe, Puerto Barrios y Puerto Santo Tomás de Castilla, departamento de Izabal

Novel evolutionary algorithm identifies interactions driving infestation of triatoma dimidiata, a chagas disease vector

Chagas disease is a lethal, neglected tropical disease. Unfortunately, aggressive insecticide-spraying campaigns have not been able to eliminate domestic infestation of Triatoma dimidiata, the native vector in Guatemala. To target interventions toward houses most at risk of infestation, comprehensive socioeconomic and entomologic surveys were conducted in two towns in Jutiapa, Guatemala. Given the exhaustively large search space associated with combinations of risk factors, traditional statistics are limited in their ability to discover risk factor interactions. Two recently developed statistical evolutionary algorithms, specifically designed to accommodate risk factor interactions and heterogeneity, were applied to this large combinatorial search space and used in tandem to identify sets of risk factor combinations associated with infestation. The optimal model includes 10 risk factors in what is known as a third-order disjunctive normal form (i.e., infested households have chicken coops AND deteriorated bedroom walls OR an accumulation of objects AND dirt floors AND total number of occupants 3 5 AND years of electricity 3 5 OR poor hygienic condition ratings AND adobe walls AND deteriorated walls AND dogs). Houses with dirt floors and deteriorated walls have been reported previously as risk factors and align well with factors currently targeted by Ecohealth interventions to minimize infestation. However, the tandem evolutionary algorithms also identified two new socioeconomic risk factors (i.e., households having many occupants and years of electricity 3 5). Identifying key risk factors may help with the development of new Ecohealth interventions and/or reduce the survey time needed to identify houses most at risk

Implementation science : epidemiology and feeding profiles of the Chagas vector Triatoma Dimidiata prior to Ecohealth intervention for three locations in Central America

This work was supported with a subsidy of the Ecohealth Initiative Program of the Center of Investigations for the Development of Canada (IDRC)(Subsidy no 106531) to Carlota Monroy; a grant from the World Health Organization (Tropical Disease Research-World Health Organization grant, TDR –WHO ID# A10249) awarded to MCM, by National Science Foundation (NSF) grant BCS-1216193 as part of the joint NSF-NIH-USDA (United States Department of Agriculture) Ecology and Evolution of Infectious Diseases program to MCM and LS and grant R03AI26268/1-2 from the National Institute of Allergy and Infectious Disease (NIAID) at the National Institutes of Health (NIH) to LS. This article was drafted and reviewed during the scientific writing workshop organized by the Program Disease Research, Department of Communicable Diseases and Health Analysis, Pan American Health Organization to support the dissemination of research funded by IDRC conducted with Ecohealth approach. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Blood feeding insects from the subfamily Triatomine are involved in the transmission of Chagas disease, caused by the protozoan parasite Trypanosoma cruzi, a neglected tropical disease endemic from southern Mexico through Central to northern South America. Chagas disease mostly affects rural areas and especially people living in houses made of lowcost, natural materials such as bajareque or adobe that have mud walls and a dirt floor. A multidisciplinary data-driven Ecohealth vector control program that includes house improvements (wall plastering and cement flooring), as well as insecticide spraying, was developed in Jutiapa department, Guatemala, and has been shown to decrease vectorhuman contact. Because Chagas vectors feed on a wide variety of vertebrates, knowing the local feeding profiles of the insect vectors before interventions can strengthen Ecohealth program development. To facilitate scaling up the Ecohealth program developed in Jutiapa to three new locations in three different countries, Texistepeque, El Salvador; San Marcos de la Sierra, Honduras and Olopa, Guatemala, and with distinct ecological scenarios, we assessed the entomological indices, feeding profiles and parasite infection of vectors collected in and around houses in the new locations prior to any interventions. Our results show all three metrics varied among locations. The results highlight the importance of domestic, synanthropic and sylvatic blood meal sources on the disease transmission cycle and the need to consider local conditions for vector control

Movimientos poblacionales de Triatoma dimidiata (Hemíptera reduviidae: Triatominae) silvestre durante un año

En un periodo de catorce meses (abril 2000 mayo 2001), se estudió el desenvolvimiento de la presencia de Triatoma dimidiata en ecotopos artificiales consistentes en seis gallineros experimentales instalados en el bosque del sitio arqueológico Yaxha1,Melchor de Mencos, Peten, de los cuales tres estaban ubicados en bosque primaria y tres en bosque perturbado o guamil. Un total de 41 insectos fueron encontrados en los seis gallineros, la mayoría de ellos (83%), permaneció menos de un mes en el gallinero en el que fueron encontrados, lo que nos indica una alta capacidad de dispersión activa por parte de las poblaciones silvestres de esta especie. Se detectó estacionalidad en la dispersión: los adultos solamente se dispersan en meses cálidos; las ninfas lo hacen todo el año, pero en mayor abundancia en los meses lluviosos. Los insectos no colonizaron los gallineros (presencia simultánea de adultos, ninfas y huevos), lo cual podría deberse a variadas preferencias de refugio, de fuentes alimenticias y la búsqueda de pareja o sitios de desove

Melhorias habitacionais com participação comunitária no controle da re-infestação por Triatoma dimidiata em Jutiapa, Guatemala

The study assessed risk factors for indoor Triatoma dimidiata infestation in Guatemala and implemented interventions in household hygiene and housing construction. Four villages with persistent (post-spraying) T. dimidiata infestation were studied. An ecosystem approach was implemented with the support of the interdisciplinary team; homeowners conducted wall improvements along with improvement of household sanitation. A new plaster mix for walls was developed and used in a separate intervention. Both interventions were associated with a reduction in infestation, but only the ecosystem approach produced important housing improvements capable of preventing re-infestation in the long term

Uncovering vector, parasite, blood meal and microbiome patterns from mixed-DNA specimens of the Chagas disease vector Triatoma dimidiata

Chagas disease, considered a neglected disease by the World Health Organization, is caused by the protozoan parasite Trypanosoma cruzi, and transmitted by \u3e140 triatomine species across the Americas. In Central America, the main vector is Triatoma dimidiata, an opportunistic blood meal feeder inhabiting both domestic and sylvatic ecotopes. Given the diversity of interacting biological agents involved in the epidemiology of Chagas disease, having simultaneous information on the dynamics of the parasite, vector, the gut microbiome of the vector, and the blood meal source would facilitate identifying key biotic factors associated with the risk of T. cruzi transmission. In this study, we developed a RADseq-based analysis pipeline to study mixed-species DNA extracted from T. dimidiata abdomens. To evaluate the efficacy of the method across spatial scales, we used a nested spatial sampling design that spanned from individual villages within Guatemala to major biogeographic regions of Central America. Information from each biotic source was distinguished with bioinformatics tools and used to evaluate the prevalence of T. cruzi infection and predominant Discrete Typing Units (DTUs) in the region, the population genetic structure of T. dimidiata, gut microbial diversity, and the blood meal history. An average of 3.25 million reads per specimen were obtained, with approximately 1% assigned to the parasite, 20% to the vector, 11% to bacteria, and 4% to putative blood meals. Using a total of 6,405 T. cruzi SNPs, we detected nine infected vectors harboring two distinct DTUs: TcI and a second unidentified strain, possibly TcIV. Vector specimens were sufficiently variable for population genomic analyses, with a total of 25,710 T. dimidiata SNPs across all samples that were sufficient to detect geographic genetic structure at both local and regional scales. We observed a diverse microbiotic community, with significantly higher bacterial species richness in infected T. dimidiata abdomens than those that were not infected. Unifrac analysis suggests a common assemblage of bacteria associated with infection, which co-occurs with the typical gut microbial community derived from the local environment. We identified vertebrate blood meals from five T. dimidiata abdomens, including chicken, dog, duck and human; however, additional detection methods would be necessary to confidently identify blood meal sources from most specimens. Overall, our study shows this method is effective for simultaneously generating genetic data on vectors and their associated parasites, along with ecological information on feeding patterns and microbial interactions that may be followed up with complementary approaches such as PCR-based parasite detection, 18S eukaryotic and 16S bacterial barcoding