University of San Simón
  • Cochabamba, Bolivia
Recent publications
Little is known about brain aging or dementia in nonindustrialized environments that are similar to how humans lived throughout evolutionary history. This paper examines brain volume (BV) in middle and old age among two indigenous South American populations, the Tsimane and Moseten, whose lifestyles and environments diverge from those in high-income nations. With a sample of 1,165 individuals aged 40 to 94, we analyze population differences in cross-sectional rates of decline in BV with age. We also assess the relationships of BV with energy biomarkers and arterial disease and compare them against findings in industrialized contexts. The analyses test three hypotheses derived from an evolutionary model of brain health, which we call the embarrassment of riches (EOR). The model hypothesizes that food energy was positively associated with late life BV in the physically active, food-limited past, but excess body mass and adiposity are now associated with reduced BV in industrialized societies in middle and older ages. We find that the relationship of BV with both non-HDL cholesterol and body mass index is curvilinear, positive from the lowest values to 1.4 to 1.6 SDs above the mean, and negative from that value to the highest values. The more acculturated Moseten exhibit a steeper decrease in BV with age than Tsimane, but still shallower than US and European populations. Lastly, aortic arteriosclerosis is associated with lower BV. Complemented by findings from the United States and Europe, our results are consistent with the EOR model, with implications for interventions to improve brain health.
La COVID-19 clínicamente se presenta con síntomas gripales y dificultad respiratoria con o sin hipoxia que puede progresar en severidad, asociado a la presencia de variantes de SARS-CoV-2 que serían responsables de reinfecciones heterólogas. Este caso muestra una secuencia de cuatro infecciones en el mismo paciente con intervalos de tiempo entre cada infección de alrededor de 5 meses coincidente con los periodos en que se presentaron cuatro olas de la infección en Bolivia. La enfermedad por COVID-19, durante el tercer episodio, fue más severa que las anteriores, con compromiso pulmonar, incremento de la Proteína C Reactiva y daño hepático. Se asume que tal situación responde a una infección heteróloga con una variante diferente a las dos anteriores y la posibilidad de desarrollo del fenómeno ADE.
Introducción: La pandemia COVID-19 ha sido un evento misceláneo, que afectó la percepción de los individuos como sujetos y las relaciones intersubjetivas, el estado como referente de representación/identidad se vio trastocado, y las condiciones de salud/enfermedad se externalizaron como resultados de las relaciones sociales, Los trastornos del estado de ánimo, el marcaje social y el miedo son efectos predecibles, por lo que conocer instrumentos validados disponibles para estudiarlos cobra relevancia. Objetivo principal: Evaluar la validez del DASS-21, FCV-19S y el cuestionario de estigma COVID-19 en el medio urbano boliviano. Método: Este trabajo examina la validez de tres instrumentos: DASS-21, FCV-19S y una traducción al español del cuestionario COVID-19 Stigma, para el contexto urbano boliviano, en un estudio piloto en la ciudad de Cochabamba compuesto por 30 sujetos aleatorizados, basado en el alfa de Cronbach y el análisis factorial. Resultados: Después de considerar el contexto, se encontró consistencia interna y validez en el cuestionario DASS-21 y Estigma, bajo condiciones sociodemográficas similares a las del piloto. Conclusión: los instrumentos validados son aptos para su aplicación en Bolivia, con las consideraciones adecuadas para optimizar su efectividad.
The necessity for green technology to generate power in rural regions is becoming more widely recognized. Stirling engines have attracted a lot of interest in recent years due to their relative ease of maintenance and simple design. Practical experience from the operation and maintenance of the Stirling engine Genoa-01 in Bolivia is the subject of this case study. The project uses a trial-and-error approach to maintain the engine in order to find relevant lessons that may be used in training of power plant personnel based in locations with limited technical resources. Analysis of the information gathered during the study identified the main challenges to overcome for small, decentralized power technologies as supply chain of spare parts, technical capacities, and promotion of the technology.
Ensuring connectivity in the countryside and cities is a key element of nature protection, allowing genetic fluxes between populations in fragmented ecosystems. We tested the hypothesis that artificial green corridors are effective for birds in the city of Cochabamba (Bolivia). We compared the following aspects of natural corridors, with generally preserved vegetation, to those of artificial corridors, constituting parks and gardens in a matrix of streets densely planted with trees: species abundance and richness, functional diversity, and the traits of bird communities. We used canonical redundancy analysis to relate species abundance to the corridor type, noise, tree vegetation structure, richness, and functional diversity. We also tested the explanatory factors for relationships with bird species richness, functional diversity, and traits. We found that most species were shared between the corridor types; the corridor type, nevertheless, had significant effects, with bird species in the green corridors being more common and heavier and having a lower beak depth/mass. By contrast, noise-reflecting urbanization deeply affected all of the studied traits, indicating large shifts in species composition. In conclusion, green corridors seem reliable enough to maintain birds at a level almost comparable to that in linear corridors, but noise is a limiting factor for efficiency for both types.
In a time of rapid global change, the question of what determines patterns in species abundance distribution remains a priority for understanding the complex dynamics of ecosystems. The constrained maximization of information entropy provides a framework for the understanding of such complex systems dynamics by a quantitative analysis of important constraints via predictions using least biased probability distributions. We apply it to over two thousand hectares of Amazonian tree inventories across seven forest types and thirteen functional traits, representing major global axes of plant strategies. Results show that constraints formed by regional relative abundances of genera explain eight times more of local relative abundances than constraints based on directional selection for specific functional traits, although the latter does show clear signals of environmental dependency. These results provide a quantitative insight by inference from large-scale data using cross-disciplinary methods, furthering our understanding of ecological dynamics.
Background Strongyloidiasis is an infectious disease that can be fatal in immunocompromised patients. Patients with end-stage renal failure who are on dialysis have a considerably weakened immune system, and organ transplantation is a major risk factor for severe strongyloidiasis. Knowledge of the local epidemiology in tropical and subtropical areas is an essential prerequisite for designing an appropriate strategy to prevent this potentially lethal complication. In this study, we aimed to estimate the prevalence and associated risk factors of S. stercoralis infection in patients on dialysis in Cochabamba, Bolivia. Methods A cross-sectional study was carried out among patients undergoing haemodialysis in Cochabamba (elevation 2,500 m, temperate climate), collecting information on socio-demographic, lifestyle, and clinical variables, and using one coproparasitological technique (the modified Baermann technique) and one serological (ELISA) test for S.stercoralis diagnosis. Results In total, 149 patients participated in the study (mean age = 51.4 years, 48.3% male). End-stage renal disease was predominantly (59%) of hypertensive and/or diabetic origin. The positive serological prevalence was 18.8% (95% CI: 13.3%–25.9%). Based on the sensitivity and specificity of the ELISA test, the estimate of the actual prevalence was 15.1% (95% CI: 9.4%–20.7%). Stool samples of 105 patients (70.5%) showed a coproparasitological prevalence of 1.9% (95% CI: 0.52%–6.68%). No potential risk factors were significantly associated with S. stercoralis infection. Conclusions We found a high seroprevalence of S. stercoralis in Bolivian patients undergoing haemodialysis in Cochabamba. We recommend presumptive antiparasitic treatment at regular intervals to avoid the potentially fatal complications of severe strongyloidiasis.
Background: Treatment guidance for children and older adult patients affected by cutaneous leishmaniasis (CL) is unclear due to limited representation of these groups in clinical trials. Methods: We conducted a collaborative retrospective study to describe the effectiveness and safety of antileishmanial treatments in children ≤ 10 and adults ≥ 60 years of age, treated between 2014 and 2018 in ten CL referral centers in Latin America. Results: 2,037 clinical records were assessed for eligibility. Of them, the main reason for non-inclusion was lack of data on treatment follow-up and therapeutic response (182/242, 75% of children and 179/468, 38% of adults). Data on 1,325 eligible CL patients (736 children and 589 older adults) were analyzed. In both age groups, disease presentation was mild, with a median number of lesions of one (IQR: 1-2) and median lesion diameter of less than 3 cm. Less than 50% of the patients had data for two or more follow-up visits post-treatment (being only 28% in pediatric patients). Systemic antimonials were the most common monotherapy regimen in both age groups (590/736, 80.2% of children and 308/589, 52.3% of older adults) with overall cure rates of 54.6% (95% CI: 50.5-58.6%) and 68.2% (95% CI: 62.6-73.4%), respectively. Other treatments used include miltefosine, amphotericin B, intralesional antimonials, and pentamidine. Adverse reactions related to the main treatment were experienced in 11.9% (86/722) of children versus 38.4% (206/537) of older adults. Most adverse reactions were of mild intensity. Conclusion: Our findings support the need for greater availability and use of alternatives to systemic antimonials, particularly local therapies, and development of strategies to improve patient follow-up across the region, with special attention to pediatric populations.
A nuclear leakage or tactical nuclear weapon use in a limited war could cause immense and long-lasting ecological consequences beyond the direct site of exposure. We call upon all scientists to communicate the importance of the environmental impacts of such an event to all life forms on Earth, including humankind. Changes to ecosystem structure and functioning and species extinctions would alter the biosphere for an unknown time frame. Radiation could trigger cascade effects in marine, atmospheric and terrestrial ecosystems of a magnitude far beyond human capabilities for mitigation or adaptation. Even a “tactical nuclear war” could alter planet Earth’s living boundaries, ending the current Anthropocene era.
Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) is a proteomic technique with proven efficiency in the identification of microorganisms, such as bacteria, fungi, and parasites. The present study aimed to evaluate the usefulness of MALDI-TOF MS for the characterization of Leishmania species circulating in Bolivia using hsp70 gene sequencing as a reference technique. 55 Leishmania strains that were isolated from patients with tegumentary leishmaniasis were analyzed. MALDI-TOF MS identified two species of the L. braziliensis complex (L. braziliensis, n = 26; L. braziliensis outlier, n = 18), one species of the L. guyanensis complex (L. guyanensis, n = 1), one species of the L. lainsoni complex (L. lainsoni, n = 2), and two species of the L. mexicana complex (L. amazonensis, n = 5; and L. garnhami, n = 3). All of the strains were correctly identified at the subgenus, genus, and complex level, but 10 of them (18%) were misidentified as other species within the same complex by the hsp70 gene sequencing, with 7 of these corresponding to possible hybrids. Thus, one L. braziliensis corresponded to L. peruviana, two L. braziliensis corresponded to L. braziliensis/L. peruviana possible hybrids, two L. amazonensis corresponded to L. mexicana, and three L. garnhami and two L. amazonensis corresponded to L. mexicana/L. amazonensis possible hybrids. Accordingly, MALDI-TOF MS could be used as an alternative to molecular techniques for the identification of Leishmania spp., as it is low cost, simple to apply, and able to quickly produce results. In Bolivia, its application would allow for the improvement of the management of patient follow-ups, the updating of the epidemiological data of the Leishmania species, and a contribution to the control of tegumentary leishmaniasis. IMPORTANCE The objective of the study was to evaluate the usefulness of MALDI-TOF MS for the characterization of Leishmania species circulating in Bolivia, in comparison with the sequencing of the hsp70 gene. In our study, all of the isolates could be identified, and no misidentifications were observed at the complex level. Although the equipment implies a high initial investment in our context, MALDI-TOF MS can be used in different areas of microbiology and significantly reduces the cost of testing. Once the parasite culture is obtained, the technique quickly yields information by accessing a free database that is available online. This would allow for the improvement of the management of patients and follow-ups, the updating of the epidemiological data of the species, and a contribution to the control of tegumentary leishmaniasis in Bolivia. Likewise, it can be used to determine a specific treatment to be given, according to the causal species of Leishmania, when there are protocols in this regard in the area.
Sustainably addressing the water needs of populations in countries lacking adequate infrastructure is challenging. We discuss the potential of decentralized water and wastewater treatment using electrified processes across Latin American countries and reflect on what would help their implementation in the region.
Background Triatoma guasayana is considered an emerging vector of Chagas disease in the Southern Cone of South America. The presence of a triatomine population with brachypterous individuals, in which both wings are reduced, has recently been reported for this species. The aim of the present study was to determine if flight-related traits varied across populations, if these traits could explain differences in flight capacity across populations and if flight-related traits are associated with geographic and/or climatic variation. Methods The study involved 66 male T. guasayana specimens from 10 triatomine populations. Digital images of wing, head and pronotum were used to estimate linear and geometric morphometric variables. Variations in size and shape were analysed using one-way analysis of variance and canonical variate analysis (CVA), respectively. Mantel tests were applied to analyse the relationship between morphometric and geographic distances, and the association between size measurements was analysed using Pearson’s correlation. We explored covariation between size and shape variables using partial least square analyses (PLS). The association of geographic and climatic variables with size measurements was tested using linear regression analyses. We performed PLS analyses for shape measurements. Results Wing size differed significantly across triatomine populations. The CVA showed that wing shape of the brachypterous population is well discriminated from that of the other populations. The Mantel test showed a positive and significant association between wing shape and geographic distances. The heads of the brachypterous population were significantly larger than those of the other populations. Similar to wing shape, the head shape of the brachypterous population was well discriminated from those of the other populations. Pronotum width did not show significant differences across populations. Geographic and climatic factors were associated with size and shape of both the wing and head, but not with pronotum width. Conclusions Most of the traits related to flight dispersal varied across populations. Wing shape and head shape were found to be better markers for differentiated morphological variation across populations. Head measurements also varied in accordance with this condition. Geographic and climatic variables were associated with most of the flight-related traits. Graphical Abstract
A growing body of work has addressed human adaptations to diverse environments using genomic data, but few studies have connected putatively selected alleles to phenotypes, much less among underrepresented populations such as Amerindians. Studies of natural selection and genotype–phenotype relationships in underrepresented populations hold potential to uncover previously undescribed loci underlying evolutionarily and biomedically relevant traits. Here, we worked with the Tsimane and the Moseten, two Amerindian populations inhabiting the Bolivian lowlands. We focused most intensively on the Tsimane, because long-term anthropological work with this group has shown that they have a high burden of both macro and microparasites, as well as minimal cardiometabolic disease or dementia. We therefore generated genome-wide genotype data for Tsimane individuals to study natural selection, and paired this with blood mRNA-seq as well as cardiometabolic and immune biomarker data generated from a larger sample that included both populations. In the Tsimane, we identified 21 regions that are candidates for selective sweeps, as well as 5 immune traits that show evidence for polygenic selection (e.g., C-reactive protein levels and the response to coronaviruses). Genes overlapping candidate regions were strongly enriched for known involvement in immune-related traits, such as abundance of lymphocytes and eosinophils. Importantly, we were also able to draw on extensive phenotype information for the Tsimane and Moseten and link five regions (containing PSD4 , MUC21 and MUC22 , TOX2 , ANXA6 , and ABCA1 ) with biomarkers of immune and metabolic function. Together, our work highlights the utility of pairing evolutionary analyses with anthropological and biomedical data to gain insight into the genetic basis of health-related traits.
Abstract In the highlands of Bolivia, native Festuca species are an important source of feed for animals due to their high tolerance to low temperatures and drought. Using simple sequence repeat (SSR) markers developed from expressed sequence tags (ESTs), the genetic diversity of 43 populations of Festuca species from Oruro, La Paz, Potosi and Cochabamba departments was evaluated for the purpose of providing information for effective conservation and breeding. In total, 64 alleles were detected across the 43 populations. SSR locus NFA 142 (with 12 alleles) had the highest number of detected alleles, while locus FES 13 (with eight alleles) had the highest polymorphism information content (PIC) at 0.55. Based on Nei’s genetic distance between populations, the unweighted pair group method with arithmetic mean (UPGMA) cluster analysis revealed two major clusters, each consisting of populations from the four departments. However, the analysis of molecular variance (AMOVA) revealed that only 5% of the total variation separated these two groups, indicating low genetic differentiation between the populations. It was also found that there was a low but significant differentiation (0.08%) between the population groups of the four departments (p = 0.01). The newly developed EST-SSR markers are highly valuable for evaluating the genetic diversity of Bolivian fescues and other related species.
The genetic etiology of Cognitive Impairment (CI) is poorly understood. This is due, in part, to the complexity of diverse genetic and environmental risk factors in large, heterogeneous study populations. To overcome this obstacle, we examined a population with low genetic heterogeneity and fewer risk factors commonly found in industrialized populations ‐ the Tsimane of Bolivia (N = 353; mean age = 69 years [60–93 years]). The Tsimane are a geographically isolated forager‐horticulturalist population with high levels of physical activity and low prevalence of coronary artery disease, hypertension, and diabetes, even at advanced ages. The absence of these typical Alzheimer’s Disease (AD)‐related comorbidities provides a novel opportunity to isolate aspects of CI that are often intertwined with cardiometabolic and other non‐communicable chronic diseases. CI was determined from field evaluations using a locally translated and adapted cognitive battery, mental status examination, informant interview, and neurological evaluation (CI = 31, AD = 1). Genome‐wide variation was characterized using the Infinum Multi‐Ethnic Global Array (1,754,170 SNPs) and evaluated with a novel analytic tool that uses biologic processes as the unit of analysis — Pathways of Distinction Analysis (PoDA). PoDA captures interactions across the multiple genes within a network and assesses significance via empiric resampling. A catalog of 1167 curated networks representing the diversity of biologic function was evaluated. The pathway that most significantly distinguishes individuals with CI from those without impairment is the KEGG Alzheimer’s Disease Pathway (Distance Score [DS] = 3.23; FDR‐adjusted pDS<0.001). This pathway is composed of 169 genes that capture the major processes associated with AD. Refined analysis identified a subset of 35 genes that is associated with a 6‐fold difference (OR = 6.26; pOR = 1.21×10−12) in relative risk for prevalent CI vs. no impairment. Those genes are involved in insulin signaling, calcium signaling, and mitochondrial oxidative phosphorylation subcomponents of the AD Pathway. It also includes variation within the AD risk loci APBB1 and MAPT (Figure 1). In a population with minimal cardiometabolic disease, pathway‐based genome analysis objectively identifies subcomponents within the AD pathway tied to cellular energy metabolism as important in CI. Following validation in larger, heterogenous populations, these components may provide targets for prevention and intervention.
Objectives: To determine the comparative efficacy and safety of a fixed dose of benznidazole (BZN) with an adjusted-dose for T. cruzi-seropositive adults without cardiomyopathy. Methods: We conducted a systematic review and individual participant data (IPD) meta-analysis following Cochrane methods, and the PRISMA-IPD statement for reporting. Randomized controlled trials (RCTs) allocating participants to fixed or adjusted doses of BZN for T. cruzi-seropositive adults without cardiomyopathy were included. We searched (December 2021) Cochrane, MEDLINE, EMBASE, LILACS and trial registries and contacted Chagas experts. Selection, data extraction, risk of bias assessment using the Cochrane tool, and a GRADE summary of finding tables were performed independently by pairs of reviewers. We conducted a random-effects IPD meta-analysis using the one-stage strategy, or, if that was impossible, the two-stage strategy. Results: Five RCTs (1198 patients) were included, none directly comparing fixed with adjusted doses of BZN. Compared to placebo, BZN therapy was strongly associated with negative qPCR and sustainable parasitological clearance regardless of the type of dose and subgroup analyzed. For negative qPCR, the fixed/adjusted rate of odds ratios (RORF/A ) was 8.83 (95%CI 1.02-76.48); for sustained parasitological clearance it was 4.60 (95%CI 0.40-52.51), probably indicating at least non-inferior effect of fixed doses, with no statistically significant interactions by scheme for global and most subgroup estimations. The RORF/A for treatment interruption due to adverse events was 0.44 (95%CI, 0.14-1.38), probably indicating no worse tolerance of fixed doses. Conclusions: We found no direct comparison between fixed and adjusted doses of BZN. However, fixed doses vs. placebo are probably not inferior to weight-adjusted doses of BZN vs. placebo in terms of parasitological efficacy and safety. Network IPD meta-analysis, through indirect comparisons, may well provide the best possible answers in the near future. Registration: The study protocol was registered in PROSPERO (CRD42019120905).
Presentamos la experiencia de la Red Latinoamericana para la Conservación de los Murciélagos (RELCOM) y los frutos que ha cosechado. RELCOM nace 15 años, en Mérida, Yucatán, México, donde un grupo de especialistas de murciélagos y líderes en sus países, se reunieron en un congreso internacional. Hoy la RELCOM reúne a 23 Programas para la Conservación de los Murciélagos de 25 países de Latinoamérica y el Caribe. El proyecto áreas importantes para la conservación de los murciélagos (AICOMs) y sitios importantes para la conservación de los murciélagos (SICOMs) surge en 2011 y hoy cuenta con mas de 200 áreas en 21 países.
Background Strongyloides stercoralis is widespread; however, there is limited information on its prevalence owing to laboratory underestimation and low clinical manifestations. The Baermann method and agar culture stand out among the parasitological techniques. Strongyloides stercoralis is present in Bolivia, but its prevalence in children remains unknown. The objective of this study was to estimate the applicability of simple parasitological techniques to increase the detection of this parasite in children living in the tropics. Methods This cross-sectional study was conducted in a tropical village in Cochabamba, Bolivia. Participants were 304 children aged 5 – 12 years who provided stool samples for different parasitological analyses (direct examination, Ritchie, Baermann, and Dancescu techniques), and their parents provided informed consent. Results Up to 64.8% of pathogenic parasites were detected using the modified Ritchie method. The Baermann technique identified 17.8% of Strongyloides stercoralis cases, and a high sensitivity with respect to the Baermann technique was only for the Dancescu technique (75.9%) that is also specific for Strongyloides stercoralis, followed by 66.7% for the modified Ritchie technique, which is used in second-line care. Discussion The Baermann technique is the best parasitological option for improving Strongyloides stercoralis diagnosis in the first-line care of the Primary Health Care System. A particular cycle of reinfection, combined with the environment and some other risk factors are related with persistence. Control is difficult without a proper diagnosis, and the Baermann technique is an approach to the solution. We conclude that with a high suspicion of the presence of Strongyloides stercoralis, the use of the Baermann technique is strongly recommended as support for direct examination in primary health care systems especially in tropical areas.
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506 members
Luis F. Aguirre
  • Centro de Biodiversidad y Genética
Rolando Claure-Del Granado
  • Hospital Obrero No 2 - C.N.S. Division of Nephrology
Danny Rejas
  • Departamento de Biología - Unidad de Limnología y Recursos Acuáticos
Mauricio Florencio Villazon
  • Facultad de Ciencias y Tecnologia
Mario Coca Morante
  • Departamento de Fitotecnía
Avenida Ballivián esquina Reza #591, Cochabamba, Bolivia