Dramatic decrease in prevalence of soil-transmitted helminths and new insights into intestinal protozoa in children living in the Chaco Region, Bolivia

We assessed the prevalence of intestinal parasites among 268 2-12-year-old children living in rural areas, small villages, and semi-urban areas of the Chaco region, south-eastern Bolivia. The overall parasitism was 69%. Only protozoa, helminths, or co-infections were observed in 89.2%, 5.9%, or 4.9% of the positive children, respectively. A significant progressive increase in overall parasite prevalence was found when passing from rural areas to small villages and semi-urban areas. The most commonly found species were Entamoeba coli (38.4%), Giardia intestinalis (37.7%), and Blastocystis spp. (16%). Hymenolepis nana was the most prevalent helminth (5.6%), followed by Ascaris lumbricoides and hookworms (1.5% and 0.4%) evidenced only in rural areas and in villages. Molecular diagnostics identified Blastocystis subtypes 9 and 2, and 5 infections by Entamoeba histolytica and 4 by Entamoeba dispar. The dramatic decrease in prevalence of soil-transmitted helminths with respect to that observed about 20 years ago (> 40%) evidences the success of the preventive chemotherapy intervention implemented in 1986. Health education and improved sanitation should be intensified to control protozoan infections

Toxicological, enzymatic, and molecular assessment of the insecticide susceptibility profile of triatoma infestans (Hemiptera: Reduviidae, Triatominae) populations from rural communities of Santa Cruz, Bolivia

A wide range of insecticide resistance profiles has been reported across Bolivian domestic and sylvatic populations of Triatoma infestans (Klug, 1834) (Hemiptera, Reduviidae), including some with levels proven to be a threat for vector control. In this work, the insecticide profile of domestic T. infestans was studied with standardized toxicological bioassays, in an area that has not undergone consistent vector control. F1 first-instar nymphs hatched in laboratory from bugs captured in three communities from the Santa Cruz Department were evaluated with different insecticides. Moreover, the enzymatic activity of esterases and cytochrome P450 monooxygenases was measured in individual insects to evaluate the possible mechanism of metabolic resistance to pyrethroids. In addition, the DNA sequence of sodium channel gene (kdr) was screened for two point mutations associated with pyrethroid resistance previously reported in T. infestans. All populations showed reduced susceptibility to deltamethrin and α-cypermethrin, albeit the RR50 values varied significantly among them. Increased P450 monooxygenases and permethrate esterases suggest the contribution, as detoxifying mechanisms, to the observed resistance to deltamethrin in all studied populations. No individuals presented either mutation associated to resistance in the kdr gene. The level of susceptibility to α-cypermethrin, the insecticide used by the local vector control program, falls within an acceptable range to continue its use in these populations. However, the observed RR50 values evidence the possibility of selection for resistance to pyrethroids, especially to deltamethrin. Consequently, the use of pyrethroid insecticides should be closely monitored in these communities, which should be kept under entomological surveillance and sustained interventions.Fil: Santo Orihuela, Pablo Luis. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Departamento de Química Analítica y Fisicoquímica. Cátedra de Química Analítica Instrumental; ArgentinaFil: Vassena, Claudia Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Carvajal, Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; ArgentinaFil: Clark, Eva. University of Alabama at Birmingahm; Estados Unidos. Baylor College; Estados UnidosFil: Menacho, Silvio. Eiti Health Center; BoliviaFil: Bozo, Ricardo. Hospital Municipal Camiri; BoliviaFil: Gilman, Robert H.. University Johns Hopkins; Estados UnidosFil: Bern, Caryn. University of California; Estados UnidosFil: Marcet, Paula Lorena. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones Científicas y Técnicas para la Defensa. Centro de Investigación de Plagas e Insecticidas; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Unidad de Investigación y Desarrollo Estratégico para la Defensa. Ministerio de Defensa. Unidad de Investigación y Desarrollo Estratégico para la Defensa; Argentin

Sustained Domestic Vector Exposure Is Associated With Increased Chagas Cardiomyopathy Risk but Decreased Parasitemia and Congenital Transmission Risk Among Young Women in Bolivia

Vector exposure showed a direct association with Chagas cardiomyopathy, but an inverse relationship with maternal parasitemia and congenital transmission. We hypothesize that repeated antigen exposure maintains an inflammatory response, increasing cardiomyopathy, but this upregulation improves control of parasitemia during pregnanc

Toward Improving Early Diagnosis of Congenital Chagas Disease in an Endemic Setting.

BACKGROUND: Congenital Trypanosoma cruzi transmission is now estimated to account for 22% of new infections, representing a significant public health problem across Latin America and internationally. Treatment during infancy is highly efficacious and well tolerated, but current assays for early detection fail to detect >50% of infected neonates, and 9-month follow-up is low. METHODS: Women who presented for delivery at 2 urban hospitals in Santa Cruz Department, Bolivia, were screened by rapid test. Specimens from infants of infected women were tested by microscopy (micromethod), quantitative PCR (qPCR), and immunoglobulin (Ig)M trypomastigote excreted-secreted antigen (TESA)-blots at birth and 1 month and by IgG serology at 6 and 9 months. RESULTS: Among 487 infants of 476 seropositive women, congenital T. cruzi infection was detected in 38 infants of 35 mothers (7.8%). In cord blood, qPCR, TESA-blot, and micromethod sensitivities/specificities were 68.6%/99.1%, 58.3%/99.1%, and 16.7%/100%, respectively. When birth and 1-month results were combined, cumulative sensitivities reached 84.2%, 73.7%, and 34.2%, respectively. Low birthweight and/or respiratory distress were reported in 11 (29%) infected infants. Infants with clinical signs had higher parasite loads and were significantly more likely to be detected by micromethod. CONCLUSIONS: The proportion of T. cruzi-infected infants with clinical signs has fallen since the 1990s, but symptomatic congenital Chagas disease still represents a significant, albeit challenging to detect, public health problem. Molecular methods could facilitate earlier diagnosis and circumvent loss to follow-up but remain logistically and economically prohibitive for routine screening in resource-limited settings

ESTUDIO EXPERIMENTAL DE UN MATERIAL FIBROCEMENTO UTILIZANDO FIBRAS DE RASTROJOS DE TRIGO

Los tableros de fibrocemento se fabrican en un proceso continuo a partir de la mezcla homogénea e íntima de cemento, agua, arena y fibras de celulosa. Se ocupan en obras de edificación, para elementos constructivos expuestos a la intemperie y también en interiores húmedos. Tradicionalmente la celulosa ocupada en la fabricación de estos productos de fibrocemento, provienen de la madera y es extraída mediante un proceso químico. Una alternativa a las fibras de madera son otras fibras vegetales, y dentro de estas, las fibras provenientes de los rastrojos (paja) de trigo son una atractiva alternativa. El presente estudio tiene por finalidad analizar la utilización de rastrojos de trigo en la confección de un nuevo material fibrocemento destinado para un uso similar al que tienen actualmente los tableros de fibrocemento tradicionales. Para esto se obtuvo fibras de celulosa de la estructura del trigo mediante métodos similares a los ocupados en la industria maderera. Específicamente el objetivo del presente estudio es estudiar las propiedades mecánicas y físicas de este nuevo material fibrocemento, desarrollando un trabajo experimental. Para la obtención de fibras celulósicas (pulpa), a partir de los rastrojos de trigo, se realizó un proceso químico de pulpaje tipo Kraft. Para la fabricación de las probetas de fibrocemento se ocupó cemento clase Portland Puzolanico grado corriente, fibras celulósicas obtenidas de los rastrojos y agua. La mezcla de fibras de trigo, cemento y agua se introdujo a un molde de acero inoxidable que permite la fabricación de una probeta de 7.2 cm. de largo y 3 cm. de ancho. Ocupando una prensa hidráulica de 50 toneladas de capacidad marca Mega modelo KCK50A, el molde es sometido a una carga que permite compactar la pasta. Para cada probeta se obtuvo la densidad, la resistencia a la flexión, y la absorción de agua. Para el pulpaje Kraft se obtuvo un rendimiento promedio de 37.24%, que es la cantidad de fibras celulósicas que se obtuvieron de los rastrojos de trigo. La resistencia a la flexión de las probetas aumenta a medida que aumenta la presión aplicada en el prensado. Se puede apreciar que las probetas que estaban constituidas de sólo cemento presentaron una diferencia significativa en la resistencia a la flexión, en comparación con las probetas que presentaron diferentes porcentajes de fibras. La resistencia a la flexión más alta se obtuvo con probetas de sólo cemento. Los valores más altos de resistencia para el compuesto se encuentran en las razones Fibra/Cemento bajas. La resistencia a la flexión del compuesto fibrocemento presenta valores máximos 10% de razón Fibras/Cemento para probetas fabricadas con razón Agua/Cemento igual a 100%; y 4% de razón Fibras/Cemento para probetas fabricadas con Agua/cemento igual a 30%. Las fibras celulósicas extraídas de los rastrojos de trigo tienen una longitud menor a la longitud de fibra crítica necesaria para reforzar en forma significativa una matriz de cemento. También estas fibras no colapsan totalmente durante el proceso de prensado, dejando espacios sin cemento en el lumen de cada una. La densidad de las probetas disminuye en forma lineal, y la absorción de agua aumenta en forma lineal, a medida que aumenta la proporción de fibras dentro del compuesto. La densidad del compuesto explica en forma satisfactoria las variaciones presentadas en la absorción de agua. La razón Agua/Cemento no presenta una influencia significativa sobre la resistencia a la flexión del fibrocemento. También no influye en las variaciones de la densidad del compuesto

Congenital Chagas disease in Santa Cruz Department, Bolivia, is dominated by Trypanosoma cruzi lineage V.

BACKGROUND: This study identified Trypanosoma cruzi discrete typing units (DTUs) in maternal and infant specimens collected from two hospitals in Bolivia, using conventional genotyping and DTU-specific serotyping. METHODS: Specimens from 142 mothers were used, including 24 seronegative and 118 seropositive individuals; 29 women transmitted T. cruzi to their infants. Maternal and infant parasite loads were determined by quantitative real-time PCR. Maternal sera were tested with an in-house parasite lysate ELISA and serotyped by a lineage-specific peptide ELISA, targeting the trypomastigote small surface antigen (TSSA). Trypanosoma cruzi genotypes in infected infants were determined by a triple PCR-RFLP assay. RESULTS: All infant specimens were genotyped as TcV. Maternal parasite loads and absorbance values by the lysate ELISA were significantly higher for transmitters compared with non-transmitters. Among seropositive mothers, 65.3% had positive results by the TSSA II/V/VI peptide ELISA. No significant difference in reactivity to TSSA II/V/VI was observed for transmitters compared with non-transmitters (79.3% vs 60.7%, respectively). CONCLUSIONS: Our findings reinforce the difficulty in obtaining sufficient sample numbers and parasite DNA to investigate the interaction between parasite genetics and the risk of congenital transmission and argue for the inclusion of DTU-specific serotyping in prospective studies

Nested logic model to determine the expansion of fuel cell electric vehicles in Spain. Sensitivity analysis of the key attributes

The use of Alternative Fuel Vehicles (AFV) as the Fuel Cell Vehicles (FCV)1, to replace vehicles powered by internal combustion engines, are a clear alternative of road transport that may provide, in the long term, security in energy supply at least partly, reduction in greenhouse gas emissions and improvement of air quality in cities. There are six areas, which should be addressed in order to guarantee market penetration of environmentally friendly cars: (a) purchase price, (b) running costs, (c) availability of refuelling stations, (d) vehicle range before refuelling, (e) refuelling time and, (f) CO2 emissions per kilometer2. Location models are intended to accelerate the market penetration of FCV, making efficient decisions about infrastructure design. Infrastructure (supply) enables to demand. However, in order for the infrastructure to be economically viable, there must already exist a given level of demand. In this work, we describe one part of the bi-level developed model, simulating the behaviour of H2 vehicle users. We use a discrete choice model to represent how users acquire FCV during the study period. The hierarchic nested logit model chosen for this study has been widely used in the field of transport. The process of choosing a FCV is the next. At the higher level a user chooses to purchase a conventional vehicle (alternative b) or an AFV (alternative a). At the lower level AFV users choose the type of alternative fuel. With the nested logit model it is possible to perform sensitivity analysis, which allows to observe how it affects each of the attributes in the usefulness of each type of vehicle and therefore the sale of the vehicle.El uso de vehículos de combustibles alternativos (AFV), como los vehículos de hidrógeno (pilas de combustible) (FCV), para reemplazar a los vehículos impulsados por motores de combustión interna, son una clara alternativa del transporte por carretera que puede proporcionar, a largo plazo, seguridad en el suministro de energía, reducción de las emisiones de gases de efecto invernadero y mejora de la calidad del aire en las ciudades. Para garantizar la penetración en el mercado de estos vehículos ecológicos, se deben abordar seis aspectos fundamentales: (a) precio de compra, (b) costes de funcionamiento, (c) disponibilidad de estaciones de repostaje, (d) autonomía de los vehículos, (e) tiempo de repostaje y (f) emisiones de CO2 por kilómetro. Con los modelos de localización se pretende acelerar la penetración de los FCV en el mercado, tomando decisiones eficientes sobre el diseño de la infraestructura. Una infraestructura adecuada (oferta) generará la demanda de estos vehículos. Sin embargo, para que la infraestructura sea económicamente viable debe de existir ya un nivel adecuado de demanda. En este trabajo, describimos una parte del modelo binivel que simula el comportamiento de los usuarios de los vehículos de H2. Utilizamos un modelo de elección discreta para representar cómo los usuarios adquieren los FCV durante el período en estudio. El modelo logit anidado jerárquico, elegido para este estudio, ha sido ampliamente utilizado en el campo del transporte. En el nivel superior del proceso de elegir un FCV, un usuario elige comprar un vehículo convencional (alternativa b) o un AFV (alternativa a). En el nivel inferior, los usuarios de AFV eligen el tipo de combustible alternativo. Con el modelo logit anidado, es posible realizar un análisis de sensibilidad que permita observar cómo afecta cada uno de los atributos a la utilidad de cada tipo de vehículo y, por tanto, a su venta.Sin financiación0.500 JCR (2017) Q4, 76/86 Engineering, MultidisciplinaryUE

Diversity, frequency and antifungal resistance of Candida species in patients with type 2 diabetes mellitus

Objective: To determine number, species of Candida and Candida resistance to antifungal therapy according to the metabolic control state and the associated salivary changes in patients with type 2 diabetes mellitus (DM2). Materials and methods: Samples of non-stimulated saliva were collected from 52 patients with DM2. Salivary pH was measured and cultured on Sabouraud glucose agar and the values of CFU/ml were calculated. The species were presumptively identified using CHROMagar Candida® plates, and identification was confirmed by polymerase chain reaction (PCR). C. albicans isolates were cultured on SGA tetracycline agar with nystatin and fluconazole diffusion disks to measure susceptibility. Results: Sixty six percent of the yeasts isolated were Candida albicans, followed by C. glabrata (20.7%). In patients with decompensated DM2, there was an inverse association between HbA1c value and salivary pH. At higher levels of salivary acidification, a greater diversity and quantity of yeasts of the genus Candida were observed. With nystatin, higher inhibition was observed at lower pH. Conclusions: The antifungal therapies could be more effective if it consider, qualitative salivary characteristics as pH, that could determine the susceptibility of species of Candida to at least to nystatin, which is the most used antifungal for treatment to oral candidiasis in patients with DM2

Epidemiology of and impact of insecticide spraying on vectorial Trypanosoma cruzi transmission in an area in the Bolivian Chaco

Residual insecticide spraying has effectively eliminated vector borne transmission of Chagas disease in many areas in South America, while in others it has failed to interrupt or sustain interruption of transmission. We describe Chagas disease epidemiology in seven contiguous villages in the Bolivian Chaco and evaluate an insecticide spraying program using a catalytic model. Community members > 2 years of age were invited to participate in a serosurvey and epidemiologic risk factor analysis. Chagas seroprevalence was 19.6% in children ≤ 15 years, 87.1% in >15 year olds, and 51.7% in the overall population. Force of infection analysis did not conclusively demonstrate an interruption in transmission. Only village of residence, age (adjusted odds ratio [aOR] = 1.16; 95% confidence interval [CI] = 1.11-1.22) and cracks in the walls of sleeping structures (aOR = 2.16; CI = 1.09-4.27) were found to be associated with disease in multivariable analysis. Catalytic models may be useful for evaluating spraying programs when pre-existing incidence data are unavailable. Sealing cracks in walls may be an efficient way to mitigate disease transmission.Fil: Samuels, Aaron. Centers For Disease Control And Prevention; Estados Unidos de América;Fil: Clark, Eva. University of Alabama School of Medicine; Estados Unidos de América;Fil: Galdos-Cardenas, Gerson. Johns Hopkins Bloomberg School of Public Health, Estados Unidos de América;Fil: Wiegand, Ryan E.. Centers For Disease Control And Prevention; Estados Unidos de América;Fil: Ferrufino, Lisbeth. Hospital Universitario Japones; Bolivia;Fil: Menacho, Silvio. Centro de Salud Elti; Bolivia;Fil: Gil, José Fernando. Universidad Nacional de Salta. Sede Regional Oran. Instituto de Investigacion de Enfermedades Tropicales; Argentina;Fil: Spicer, Jennife. Emory University School of Medicine; Estados Unidos de América;Fil: Budde, Julia. Emory University School of Medicine; Estados Unidos de América;Fil: Levy, Michael Z.. University Of Pennsylvania; Estados Unidos de América;Fil: Bozo Gutierrez, Ricardo W.. Hospital Municipal Camiri; Bolivia;Fil: Gilman, Robert H.. Johns Hopkins Bloomberg School of Public Health, Estados Unidos de América;Fil: Bern, Caryn. Global Health Science; Estados Unidos de América