Ecological host fitting of Trypanosoma cruzi TcI in Bolivia: mosaic population structure, hybridization and a role for humans in Andean parasite dispersal.

An improved understanding of how a parasite species exploits its genetic repertoire to colonize novel hosts and environmental niches is crucial to establish the epidemiological risk associated with emergent pathogenic genotypes. Trypanosoma cruzi, a genetically heterogeneous, multi-host zoonosis, provides an ideal system to examine the sylvatic diversification of parasitic protozoa. In Bolivia, T. cruzi I, the oldest and most widespread genetic lineage, is pervasive across a range of ecological clines. High-resolution nuclear (26 loci) and mitochondrial (10 loci) genotyping of 199 contemporaneous sylvatic TcI clones was undertaken to provide insights into the biogeographical basis of T. cruzi evolution. Three distinct sylvatic parasite transmission cycles were identified: one highland population among terrestrial rodent and triatomine species, composed of genetically homogenous strains (Ar = 2.95; PA/L = 0.61; DAS = 0.151), and two highly diverse, parasite assemblages circulating among predominantly arboreal mammals and vectors in the lowlands (Ar = 3.40 and 3.93; PA/L = 1.12 and 0.60; DAS = 0.425 and 0.311, respectively). Very limited gene flow between neighbouring terrestrial highland and arboreal lowland areas (distance ~220 km; FST = 0.42 and 0.35) but strong connectivity between ecologically similar but geographically disparate terrestrial highland ecotopes (distance >465 km; FST = 0.016-0.084) strongly supports ecological host fitting as the predominant mechanism of parasite diversification. Dissimilar heterozygosity estimates (excess in highlands, deficit in lowlands) and mitochondrial introgression among lowland strains may indicate fundamental differences in mating strategies between populations. Finally, accelerated parasite dissemination between densely populated, highland areas, compared to uninhabited lowland foci, likely reflects passive, long-range anthroponotic dispersal. The impact of humans on the risk of epizootic Chagas disease transmission in Bolivia is discussed

PROPUESTA DE UN PLAN ESTRATÉGICO PARA LA EMPRESA MULTISERVICIOS DIR - CHOTA 2018

La presente investigación se llevó a cabo en la empresa Multiservicios DIR - Chota, el cual tuvo como objetivo general proponer un plan estratégico para la empresa MULTISERVICIOS DIR. CHOTA, 2018. El problema central del estudio se formuló bajo la siguiente interrogante ¿ Cuál es el plan estratégico para la empresa Multiservicios DIR – Chota 2018, con el fin de mejorar sus procesos, y a su vez optimizar sus resultados? La metodología se centró en un estudio de diseño no experimental transversal, de enfoque cuantitativo, de tipo descriptiva, la recolección de datos se realizó mediante un cuestionario, el cual fue aplicado sobre una muestra de 32 trabajadores de la empresa. Se concluye que la empresa opera de forma empírica, sin seguir lineamientos estratégicos, por lo cual los trabajadores desconocen la misión y visión de la empresa, además afirman que no tienen metas establecidas ni se formulan estrategias para lograr el crecimiento de la empresa. Se recomienda la aplicación del plan estratégico desarrollado con el fin de potenciar las fortalezas de la empresa y lograr ser competitiva en el mercado.Tesi

PROPUESTA DE UN PLAN ESTRATÉGICO PARA LA EMPRESA MULTISERVICIOS DIR - CHOTA 2018

TesisLa presente investigación se llevó a cabo en la empresa Multiservicios DIR - Chota, el cual tuvo como objetivo general proponer un plan estratégico para la empresa MULTISERVICIOS DIR. CHOTA, 2018. El problema central del estudio se formuló bajo la siguiente interrogante ¿ Cuál es el plan estratégico para la empresa Multiservicios DIR – Chota 2018, con el fin de mejorar sus procesos, y a su vez optimizar sus resultados? La metodología se centró en un estudio de diseño no experimental transversal, de enfoque cuantitativo, de tipo descriptiva, la recolección de datos se realizó mediante un cuestionario, el cual fue aplicado sobre una muestra de 32 trabajadores de la empresa. Se concluye que la empresa opera de forma empírica, sin seguir lineamientos estratégicos, por lo cual los trabajadores desconocen la misión y visión de la empresa, además afirman que no tienen metas establecidas ni se formulan estrategias para lograr el crecimiento de la empresa. Se recomienda la aplicación del plan estratégico desarrollado con el fin de potenciar las fortalezas de la empresa y lograr ser competitiva en el mercado

Distribution of Pyrethroid Resistant Populations of Triatoma infestans in the Southern Cone of South America

A number of studies published during the last 15 years showed the occurrence of insecticide resistance in Triatoma infestans populations. The different toxicological profiles and mechanisms of resistance to insecticides is due to a genetic base and environmental factors, being the insecticide selective pressure the best studied among the last factors. The studies on insecticide resistance on T. infestans did not consider the effect of environmental factors that may influence the distribution of resistance to pyrethroid insecticides. To fill this knowledge gap, the present study aims at studying the association between the spatial distribution of pyrethroid resistant populations of T. infestans and environmental variables. A total of 24 articles reporting on studies that evaluated the susceptibility to pyrethroids of 222 field-collected T. infestans populations were compiled. The relationship between resistance occurrence (according to different criteria) with environmental variables was studied using a generalized linear model. The lethal dose that kills 50% of the evaluated population (LD 50 ) showed a strong linear relationship with the corresponding resistance ratio (RR 50 ). The statistical descriptive analysis of showed that the frequency distribution of the Log(LD 50 ) is bimodal, suggesting the existence of two statistical groups. A significant model including 5 environmental variables shows the geographic distribution of high and low LD 50 groups with a particular concentration of the highest LD 50 populations over the region identified as the putative center of dispersion of T. infestans.The occurrence of these two groups concentrated over a particular region that coincides with the area where populations of the intermediate cytogenetic group were found might reflect the spatial heterogeneity of the genetic variability of T. infestans, that seems to be the cause of the insecticide resistance in the area, even on sylvatic populations of T. infestans, never before exposed to pyrethroid insecticides, representing natural and wild toxicological phenotypes. The strong linear relationship found between LD 50 and RR 50 suggest RR 50 might not be the best indicator of insecticide resistance in triatomines.Fil: Bustamante Gomez, Marinely. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomínueos e Epidemiologia da Doença de Chagas; BrasilFil: Gonçalves Diotaiuti, Liléia. Centro de Pesquisas René Rachou. Laboratório de Referência em Triatomínueos e Epidemiologia da Doença de Chagas; BrasilFil: Gorla, David Eladio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin

Geographic distribution of the 222 <i>T</i>. <i>infestans</i> populations evaluated for susceptibility to pyrethroids.

<p>Red circles: populations identified as resistant by PAHO and WHO criteria (RR₅₀> 5 or mortality DD <80%); blue circles: populations identified as susceptible by PAHO and WHO criteria (RR₅₀ < 5 or mortality DD > 80%).</p

Frequency distribution of Log (LD₅₀) in the <i>T</i>. <i>infestans</i> studied populations (n = 141).

<p>The value Log (LD₅₀) = 2.6 (equivalent to 13.6 ng a.i./insect) is the threshold value that best separates the two subpopulations.</p

Best GLM models for each response variable as a function of bioclimatic variables (Bioxx).

<p>Response variables are of binary type (0,1).</p