Integrated vector control of Chagas disease in Guatemala : a case of social innovation in health

An interdisciplinary team from the Laboratory of Applied Entomology and Parasitology (LENAP) of the Universidad de San Carlos (USAC), in collaboration with communities of Comapa, Guatemala, developed an effective solution to address the risk for Chagas disease. This article describes how the integration of criteria of social innovation into a home improvement strategy for Chagas disease control, can generate processes of transformation in health by considering sociocultural conditions. The case study revealed that home improvement conditions motivated women and their families to adopt new and health-promoting practices that also favorably impacted household and community economies

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

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

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

Factores de riesgo para la infestación intradomiciliaria por el vector de la enfermedad de Chagas, Triatoma dimidiata, en Jutiapa, Guatemala

The study evaluates variables such as hygienic and construction conditions of households, cultural practices, and socioeconomic status, as possible risk factors for intradomiciliary infestation by Triatoma dimidiata. Similar to other triatomines that form domestic colonies, T. dimidiata hides in cracks in earthen/adobe walls, under loose plaster, behind furniture, behind pictures or other wall ornaments, and under bed mattresses. The hygiene and construction practices of rural houses make them suitable for infestation and are directly linked to socioeconomic status and cultural practices. Approaches to control must include better wall plastering and sanitation.Seiscientas cuarenta y cuatro casas en Jutiapa, Guatemala fueron encuestadas en el año 2004 para buscar el vector de la enfermedad de Chagas Triatoma dimidiata. Diecisiete variables relacionadas con las condiciones estructurales y de higiene de las casas fueron registradas y evaluadas como factores de riesgo para la infestación intradomiciliar con T. dimidiata. Análisis chi-cuadrado detectaron asociaciones significativas entre la presencia del vector y 8 de estas variables. En modelos log-lineares se detectó, que sin importar la antigüedad de la casa, las posibilidades de presencia del vector fueron 4,3 y 10 veces más bajas en casas con un buen estado socioeconómico que en casas pobres o muy pobres, respectivamente. Además, las posibilidades de infestación fueron mayores en casas con paredes sin repello (3,85 veces) o con repellado incompleto o de mala calidad (4,56 veces), que con repellado completo. Las estrategias para el control de T. dimidiata deberían incluir la introducción de repellos baratos y de buena calidad y la promoción de mejores prácticas sanitarias. Estas estrategias no solo reducirían o eliminaría la infestación, sino también ayudaría a prevenir la reinfestación

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

Revisión de 13 especies de la familia Triatominae (Hemiptera: Reduviidae) vectores de la enfermedad de Chagas, en México

Vectors of Trypanosoma cruzi, parasite responsible for Chagas disease, are divided in intradomestic, peridomestic andsylvatic. The intradomestic are Triatoma barberi and Triatoma dimidiata, two species that represent the highest healthrisk among the Mexican population. Triatoma dimidiata is a species found mainly inside human habitats, but inYucatan, it corresponds to the peridomicile vectors. Also in the peridomicile most of Chagas disease vectors arefound: Meccus bassolsae, M. longipennis, M. mazzottii, M pallidipennis, M. phyllosomus, M picturata, Triatomagerstaeckeri, T mexicana, T rubida, Dipetalogaster máxima (the last two are in the process of becoming adapted tothe domicile), Panstrongylus rufotuberculatus which occasionally enters the domicile in its adult stage, and Rhodniusprolixus, which is practically controlled in the country. Peridomestic vectors are of lower risk in the transmissiondynamics, as compared to the intradomestic ones. For the control of the intradomestic vectors, health educationprograms, improvements of housing, and the use of pesticides are essential To control the peridomestic vectors, healtheducation programs are required, as well as the use of mosquito nets on doors and windows and around beds, asidefrom cementing the stone wall fences.Los transmisores de Trypanosoma cruzi, flagelado causante de la enfermedad, se dividen en intradomiciliados,peridomiciliados y silvestres. Entre los intradomiciliados se encuentran, Triatoma barberi y Triatoma dimidiata, queson los que representan un mayor riesgo para la Salud Pública, en México. Aunque Triatoma dimidiata se encuentraprincipalmente dentro de la vivienda, en Yucatán tiene un comportamiento peridomiciliar, dentro de este grupo seencuentran la mayoría de los transmisores de la enfermedad de Chagas Meccus longipennis, M. mazzottii, M.pallidipennis, M. phyllosomus, M. picturatus, Triatoma gerstaeckeri, T. mexicana, T. rubida, Dipetalogaster máxima,Panstrongylus rufotuberculatus y Rhodnius prolixus. Los transmisores peridomiciliados son de menor riesgo en ladinámica de transmisión comparados con los intradomiciliados. Para el control de los transmisores intradomiciliados,se deben emplear programas de educación para la salud, mejoramiento de vivienda e insecticidas; mientras que paralos vectores visitantes o peridomiciliados, son necesarios programas de educación para la salud, uso de mosquiteros,pabellones y cementación de las bardas de piedra

Phylogeographic pattern and extensive mitochondrial DNA divergence disclose a species complex within the Chagas disease vector Triatoma dimidiata.

ABSTARCT: Previous studies have shown that "bioequivalent" generic products of vancomycin are less effective in vivo against Staphylococcus aureus than the innovator compound. Considering that suboptimal bactericidal effect has been associated with emergence of resistance, we aimed to assess in vivo the impact of exposure to innovator and generic products of vancomycin on S. aureus susceptibility. A clinical methicillin-resistant S. aureus (MRSA) strain from a liver transplant patient with persistent bacteremia was used for which MIC, minimum bactericidal concentration (MBC), and autolytic properties were determined. Susceptibility was also assessed by determining a population analysis profile (PAP) with vancomycin concentrations from 0 to 5 mg/liter. ICR neutropenic mice were inoculated in each thigh with ∼7.0 log(10) CFU. Treatment with the different vancomycin products (innovator and three generics; 1,200 mg/kg of body weight/day every 3 h) started 2 h later while the control group received sterile saline. After 24 h, mice were euthanized, and the thigh homogenates were plated. Recovered colonies were reinoculated to new groups of animals, and the exposure-recovery process was repeated until 12 cycles were completed. The evolution of resistance was assessed by PAP after cycles 5, 10, 11, and 12. The initial isolate displayed reduced autolysis and higher resistance frequencies than S. aureus ATCC 29213 but without vancomycin-intermediate S. aureus (VISA) subpopulations. After 12 cycles, innovator vancomycin had significantly reduced resistant subpopulations at 1, 2, and 3 mg/liter, while the generic products had enriched them progressively by orders of magnitude. The great capacity of generic vancomycin to select for less susceptible organisms raises concerns about the role of therapeutic inequivalence of any antimicrobial on the epidemiology of resistance worldwide

Ecology and Control of Triatomine (Hemiptera: Reduviidae) Vectors of Chagas Disease in Guatemala, Central America

This thesis analyses several factors affecting the control of triatomines in Guatemala. There are three synantropic triatomines in Guatemala, i.e., Rhodnius prolixus, Triatoma dimidiata and T. nitida. Their distibution is mainly at an altitude between 800 and 1500 m a.s.l. R. prolixus and T. nitida have localized but scaterred distibution while T. dimidiata is present in 21 of the 22 departments in the country. Several investigations have shown that R. prolixus could be relatively easily eradicated while T. dimidiata may be more difficult to control, since it is present in domestic, peridomestic and sylvatic environments showing high diversity and a variety of epidemiological characteristics. Based on the incidence of Trypanosma cruzi infection in humans in the distributional areas of the triatomines, R. prolixus appear to be a more competent vector than T. dimidiata. This is despite the fact that these vectors have similar infection rates. Inside houses, R. prolixus and T. dimidiata and in artificial environments, T. ryckmani and T. dimidiata, preferred the northern side of the walls. Therefore, selective application of insecticides should focus on walls and furniture located in the northern part of the house. House improvements reduced the infestation of triatomines, and could be used as a complement to insecticidal spraying. Although T. dimidiata is not an efficient vector its wide distribution, versatility in occupying different habitats and capacity to disperse render this species difficult to control in Central America. Thus, only few months after insecticidal spraying T. dimidiata had reinfested the domestic environments. Morphometic methodology and genetic markers have been developed to differentiate within-species populations of T. dimidiata and T. nitida. Studies on the migration patterns of sylvatic T. dimidiata and T. ryckmani have been performed in order to clarify the colonization patterns. The adults migrate, in particular, in the dry part of the year. This finding may be of help in attempts to control T. dimidiata