Harnessing Bioluminescent Bacteria to Develop an Enzymatic-free Enzyme-linked immunosorbent assay for the Detection of Clinically Relevant Biomarkers.

Enzyme-linked immunosorbent assay (ELISA) is the gold standard technique for measuring protein biomarkers due to its high sensitivity, specificity, and throughput. Despite its success, continuous advancements in ELISA and immunoassay formats are crucial to meet evolving global challenges and to address new analytical needs in diverse applications. To expand the capabilities and applications of immunoassays, we introduce a novel ELISA-like assay that we call Bioluminescent-bacteria-linked immunosorbent assay (BBLISA). BBLISA is an enzyme-free assay that utilizes the inner filter effect between the bioluminescent bacteriaAllivibrio fischeriand metallic nanoparticles (gold nanoparticles and gold iridium oxide nanoflowers) as molecular absorbers. Functionalizing these nanoparticles with antibodies induces their accumulation in wells upon binding to molecular targets, forming the classical immune-sandwich complex. Thanks to their ability to adsorb the light emitted by the bacteria, the nanoparticles can suppress the bioluminescence signal, allowing the rapid quantification of the target. To demonstrate the bioanalytical properties of the novel immunoassay platform, as a proof of principle, we detected two clinically relevant biomarkers (human immunoglobulin G and SARS-CoV-2 nucleoprotein) in human serum, achieving the same sensitivity and precision as the classic ELISA. We believe that BBLISA can be a promising alternative to the standard ELISA techniques, offering potential advancements in biomarker detection and analysis by combining nanomaterials with a low-cost, portable bioluminescent platform.

Selection and characterisation of bioreceptors to develop nanoparticle-based lateral-flow immunoassays in the context of the SARS-CoV-2 outbreak.

This manuscript aims at raising the attention of the scientific community to the need for better characterised bioreceptors for fast development of point-of-care diagnostic devices able to support mass frequency testing. Particularly, we present the difficulties encountered in finding suitable antibodies for the development of a lateral flow assay for detecting the nucleoprotein of SARS-CoV-2.

Litiasis vesical gigante recurrente en el adulto. Reporte de un caso / Recurrent giant bladder stones in the adult.Case report

RESUMEN La ocurrencia de casos de cálculos urinarios considerados como gigantes ha disminuido sensiblemente en su frecuencia desde el advenimiento de los antibióticos y el control apropiado de las infecciones urinarias. El diagnóstico de los mismos se da por sintomatología y estudios de imágenes. Se presenta el caso clínico de un hombre de 59 años de edad con litiasis vesical gigante recurrente. El paciente fue diagnosticado de dos litiasis de origen vesical tras realización de una tomografía axial computarizada del aparato urinario y posteriormente se le realizó una cistolitotomía para extracción de los cálculos de hasta 1435 g. El análisis morfoconstitucional de los cálculos reveló a la Brushita, Carbapatita y Estruvita como componentes principales. La evaluación metabólica señaló presencia de hipocitraturia e hiperoxaluria. Es el primer reporte en el país acerca de una litiasis gigante en que la composición de los cálculos indicaría procesos infecciosos como posibles causas de formación.

ABSTRACT The occurrence of cases of urinary stones considered as giant has decreased significantly in its frequency since the advent of antibiotics and the appropriate control of urinary tract infections. The diagnosis of them is based on symptomatology and imaging studies. We present a case of a 59-year-old man with recurrent giant bladder stones. The patient was diagnosed with two vesical stones after performing a computerized axial tomography of the urinary system and later a cystolithotomy was performed to remove stones of up to 1,435 g. The morphoconstitutional analysis of the calculus revealed brushite, carbapatite and struvite as main components. The metabolic evaluation indicated the presence of hypocitraturia and hyperoxaluria.This is the first report in the country of a giant lithiasis in which the composition of the stones would indicate infectious processes as the possible causes of formation.

Fetal ischemia monitoring with in vivo implanted electrochemical multiparametric microsensors.

Under intrauterine growth restriction (IUGR), abnormal attainment of the nutrients and oxygen by the fetus restricts the normal evolution of the prenatal causing in many cases high morbidity being one of the top-ten causes of neonatal death. The current gold standards in hospitals to detect this relevant problem is the clinical observation by echography, cardiotocography and Doppler. These qualitative techniques are not conclusive and requires risky invasive fetal scalp blood testing and/or amniocentesis. We developed micro-implantable multiparametric electrochemical sensors for measuring ischemia in real time in fetal tissue and vascular. This implantable technology is designed to continuous monitoring for an early detection of ischemia to avoid potential fetal injury. Two miniaturized electrochemical sensors were developed based on oxygen and pH detection. The sensors were optimized in vitro under controlled concentration, to assess the selectivity and sensitivity required. The sensors were then validated in vivo in the ewe fetus model, by means of their insertion in the muscle leg and inside the iliac artery of the fetus. Ischemia was achieved by gradually obstructing the umbilical cord to regulate the amount of blood reaching the fetus. An important challenge in fetal monitoring is the detection of low levels of oxygen and pH changes under ischemic conditions, requiring high sensitivity sensors. Significant differences were observed in both; pH and pO2 sensors under changes from normoxia to hypoxia states in the fetus tissue and vascular with both sensors. Herein, we demonstrate the feasibility of the developed sensors for future fetal monitoring in medical applications.

Miniaturized Electrochemical Sensors to Monitor Fetal Hypoxia and Acidosis in a Pregnant Sheep Model.

Perinatal asphyxia is a major cause of severe brain damage and death. For its prenatal identification, Doppler ultrasound has been used as a surrogate marker of fetal hypoxia. However, Doppler evaluation cannot be performed continuously. We have evaluated the performance of a miniaturized multiparametric sensor aiming to evaluate tissular oxygen and pH changes continuously in an umbilical cord occlusion (UCO) sheep model. The electrochemical sensors were inserted in fetal hindlimb skeletal muscle and electrochemical signals were recorded. Fetal hemodynamic changes and metabolic status were also monitored during the experiment. Additionally, histological assessment of the tissue surrounding the sensors was performed. Both electrochemical sensors detected the pO2 and pH changes induced by the UCO and these changes were correlated with hemodynamic parameters as well as with pH and oxygen content in the blood. Finally, histological assessment revealed no signs of alteration on the same day of insertion. This study provides the first evidence showing the application of miniaturized multiparametric electrochemical sensors detecting changes in oxygen and pH in skeletal muscular tissue in a fetal sheep model.

Nanodiagnostics to Face SARS-CoV-2 and Future Pandemics: From an Idea to the Market and Beyond.

The COVID-19 pandemic made clear how our society requires quickly available tools to address emerging healthcare issues. Diagnostic assays and devices are used every day to screen for COVID-19 positive patients, with the aim to decide the appropriate treatment and containment measures. In this context, we would have expected to see the use of the most recent diagnostic technologies worldwide, including the advanced ones such as nano-biosensors capable to provide faster, more sensitive, cheaper, and high-throughput results than the standard polymerase chain reaction and lateral flow assays. Here we discuss why that has not been the case and why all the exciting diagnostic strategies published on a daily basis in peer-reviewed journals are not yet successful in reaching the market and being implemented in the clinical practice.

The Microbiome Meets Nanotechnology: Opportunities and Challenges in Developing New Diagnostic Devices.

Monitoring of the human microbiome is an emerging area of diagnostics for personalized medicine. Here, the potential of different nanomaterials and nanobiosensing technologies is reviewed for the development of novel diagnostic devices for the detection and measurement of microbiome-related biomarkers. Moreover, the current and future landscape of microbiome-based diagnostics is defined by exploring the advantages and disadvantages of current nanotechnology-based approaches, especially in the context of developing point-of-care (PoC) devices that would meet the international guidelines known as REASSURED (Real-time connectivity; Ease of specimen collection; Affordability; Sensitivity; Specificity; User-friendliness; Rapid & robust operation; Equipment-free; and Deliverability). Finally, the strategies of the latest international scientific consortia working in this field are analyzed, the current microbiome diagnostics market are reported and the principal ethical, legal, and societal issues related to microbiome R&D and innovation are discussed.

in vivo Monitoring with micro-implantable hypoxia sensor based on tissue acidosis.

Hypoxia is a common medical problem, sometimes difficult to detect and caused by different situations. Control of hypoxia is of great medical importance and early detection is essential to prevent life threatening complications. However, the few current methods are invasive, expensive, and risky. Thus, the development of reliable and accurate sensors for the continuous monitoring of hypoxia is of vital importance for clinical monitoring. Herein, we report an implantable sensor to address these needs. The developed device is a low-cost, miniaturised implantable electrochemical sensor for monitoring hypoxia in tissue by means of pH detection. This technology is based on protonation/deprotonation of polypyrrole conductive polymer. The sensor was optimized in vitro and tested in vivo intramuscularly and ex vivo in blood in adult rabbits with respiration-induced hypoxia and correlated with the standard device ePOCTM. The sensor demonstrated excellent sensitivity and reproducibility; 46.4 ± 0.4 mV/pH in the pH range of 4-9 and the selectivity coefficient exhibited low interference activity in vitro. The device was linear (R2 = 0.925) with a low dispersion of the values (n = 11) with a cut-off of 7.1 for hypoxia in vivo and ex vivo. Statistics with one-way ANOVA (α = 0.05), shows statistical differences between hypoxia and normoxia states and the good performance of the pH sensor, which demonstrated good agreement with the standard device. The sensor was stable and functional after 18 months. The excellent results demonstrated the feasibility of the sensors in real-time monitoring of intramuscular tissue and blood for medical applications.

Tutorial: design and fabrication of nanoparticle-based lateral-flow immunoassays.

Lateral-flow assays (LFAs) are quick, simple and cheap assays to analyze various samples at the point of care or in the field, making them one of the most widespread biosensors currently available. They have been successfully employed for the detection of a myriad of different targets (ranging from atoms up to whole cells) in all type of samples (including water, blood, foodstuff and environmental samples). Their operation relies on the capillary flow of the sample throughout a series of sequential pads, each with different functionalities aiming to generate a signal to indicate the absence/presence (and, in some cases, the concentration) of the analyte of interest. To have a user-friendly operation, their development requires the optimization of multiple, interconnected parameters that may overwhelm new developers. In this tutorial, we provide the readers with: (i) the basic knowledge to understand the principles governing an LFA and to take informed decisions during lateral flow strip design and fabrication, (ii) a roadmap for optimal LFA development independent of the specific application, (iii) a step-by-step example procedure for the assembly and operation of an LF strip for the detection of human IgG and (iv) an extensive troubleshooting section addressing the most frequent issues in designing, assembling and using LFAs. By changing only the receptors, the provided example procedure can easily be adapted for cost-efficient detection of a broad variety of targets.

Micro-needle implantable electrochemical oxygen sensor: ex-vivo and in-vivo studies.

Oxygen is vital for energy metabolism in mammals and the variability of the concentration is considered a clinical alert for a wide range of metabolic malfunctions in medicine. In this article, we describe the development and application of a micro-needle implantable platinum-based electrochemical sensor for measuring partial pressure of oxygen in intramuscular tissue (in-vivo) and vascular blood (ex-vivo). The Pt-Nafion® sensor was characterized morphological and electrochemically showing a higher sensitivity of -2.496 nA/mmHg (-1.495 nA/µM) when comparing with its bare counterpart. Our sensor was able to discriminate states with different oxygen partial pressures (pO2) for ex-vivo (blood) following the same trend of the commercial gas analyzer used as standard. For in-vivo (intramuscular) experiments, since there is not a gold standard for measuring pO2 in tissue, it was not possible to correlate the obtained currents with the pO2 in tissue. However, our sensor was able to detect clear statistical differences of O2 between hyperoxia and hypoxia states in tissue.

Estado nutricional-hematológico y parasitosis intestinal de niños escolares de 5 a 12 años de cuatro localidades rurales de Paraguay / Nutritional-hematological status and intestinal parasitosis of school children aged 5 to 12 years in four rural localities of Paraguay

El mundo, actualmente se enfrenta a una doble carga de malnutrición que incluye la desnutrición y la alimentación excesiva. A ello se suman las parasitosis intestinales que es una enfermedad frecuente con importante morbimortalidad en la población infantil, ligadas a la pobreza y malas condiciones higiénico-sanitarias. El objetivo de este trabajo fue describir el estado nutricional-hematológico y parasitológico de niños escolares de cuatro comunidades rurales de Paraguay. Estudio observacional descriptivo de corte transverso en el que participaron 102 niños de ambos sexos de 5 a 12 años de edad. Se realizó medición de peso y talla, utilizando balanza calibrada, y un altímetro fijado a la pared. Toma de muestra sanguínea por punción venosa para determinación de parámetros hematológicos, procesados en contador hematológico por impedancia. Muestras de heces de una sola toma fueron recogidas en frascos apropiados con formol al 10%, utilizándose 4 métodos: directo, flotación de Willis, Graham y de concentración. En relación al estado nutricional-hematológico se encontró que el 3,9% de los niños estaba con desnutrición moderada y el 9,8% presentó riesgo de desnutrición; anemia se observó en el 38,2% de los niños. En relación a la parasitosis, el estudio diagnóstico se realizó a 94 niños y se encontró que el 72,2% estaba parasitado, siendo Blastocystis hominis el más frecuente. Tanto la frecuencia de anemia como de parasitosis es alta en esta población, sin embargo no se pudo establecer una relación entre ellas(AU)

A vertical flow paper-microarray assay with isothermal DNA amplification for detection of Neisseria meningitidis.

Paper-based biosensors offer a promising technology to be used at the point of care, enabled by good performance, convenience and low-cost. In this article, we describe a colorimetric vertical-flow DNA microarray (DNA-VFM) that takes advantage of the screening capability of DNA microarrays in a paper format together with isothermal amplification by means of Recombinase Polymerase Amplification (RPA). Different assay parameters such as hybridization buffer, flow rate, printing buffer and capture probe concentration were optimized. A limit of detection (LOD) of 4.4 nM was achieved as determined by tabletop scanning. The DNA-VFM was applied as a proof of concept for detection of Neisseria meningitidis, a primary cause of bacterial meningitis. The LOD was determined to be between 38 and 2.1 × 106 copies/VFMassay, depending on the choice of DNA capture probes. The presented approach provides multiplex capabilities of DNA microarrays in a paper-based format for future point-of-care applications.

Health care workers' perceptions of point-of-care testing in a low-income country-A qualitative study in Southwestern Uganda.

BACKGROUND: Point-of-care (POC) tests have become increasingly available and more widely used in recent years. They have been of particular importance to low-income settings, enabling them with clinical capacities that had previously been limited. POC testing programs hold a great potential for significant improvement in low-income health systems. However, as most POC tests are developed in high-income countries, disengagement between developers and end-users inhibit their full potential. This study explores perceptions of POC test end-users in a low-income setting, aiming to support the development of novel POC tests for low-income countries. METHODS: A qualitative study was conducted in Mbarara District, Southwestern Uganda, in October 2014. Fifty health care workers were included in seven focus groups, comprising midwives, laboratory technicians, clinical and medical officers, junior and senior nurses, and medical doctors. Discussions were audio-recorded and transcribed verbatim. Transcripts were coded through a data-driven approach for qualitative content analysis. RESULTS: Nineteen different POC tests were identified as currently being in use. While participants displayed being widely accustomed to and appreciative of the use of POC tests, they also assessed the use and characteristics of current tests as imperfect. An ideal POC test was characterized as being adapted to local conditions, thoughtfully implemented in the specific health system, and capable of improving the care of patients. Tests for specific medical conditions were requested. Opinions differed with regard to the ideal distribution of POC tests in the local health system. CONCLUSION: POC tests are commonly used and greatly appreciated in this study setting. However, there are dissatisfactions with current POC tests and their use. To maximize benefit, stakeholders need to include end-user perspectives in the development and implementation of POC tests. Insights from this study will influence our ongoing efforts to develop POC tests that will be particularly usable in low-income settings.

Electrochemically reduced graphene and iridium oxide nanoparticles for inhibition-based angiotensin-converting enzyme inhibitor detection.

In this work, a novel biosensor based on electrochemically reduced graphene oxide and iridium oxide nanoparticles for the detection of angiotensin-converting enzyme inhibitor drug, captopril, is presented. For the preparation of the biosensor, tyrosinase is immobilized onto screen printed electrode by using 1-Ethyl-3-(3-dimethylaminopropyl)-carbodiimide and N-Hydroxysuccinimide coupling reagents, in electrochemically reduced graphene oxide and iridium oxide nanoparticles matrix. Biosensor response is characterized towards catechol, in terms of graphene oxide concentration, number of cycles to reduce graphene oxide, volume of iridium oxide nanoparticles and tyrosinase solution. The designed biosensor is used to inhibit tyrosinase activity by Captopril, which is generally used to treat congestive heart failure. It is an angiotensin-converting enzyme inhibitor that operates via chelating copper at the active site of tyrosinase and thioquinone formation. The captopril detections using both inhibition ways are very sensitive with low limits of detection: 0.019µM and 0.008µM for chelating copper at the active site of tyrosinase and thioquinone formation, respectively. The proposed methods have been successfully applied in captopril determination in spiked human serum and pharmaceutical dosage forms with acceptable recovery values.

[Lithogenic risk in patients from Paraguay with urolithiasis]. / Perfil de riesgo litogénico en pacientes con urolitiasis en Paraguay.

UNLABELLED: The lithogenic risk profile is a graphical representation of metabolic factors and urinary saturation involved in the stone formation with their respective critical values. AIM: To determine the lithogenic risk profile in patients with urolithiasis. MATERIAL AND METHODS: Personal data such as anthropometric, history of diseases and family history of urolithiasis were recorded. Different compounds acting as promoters or inhibitors of crystallization were measured in serum and urine samples, and the data obtained were used to calculate urinary saturation using Equil software. RESULTS: We included 30 men and 43 women with a median age of 45 (34-54) years. Overweight and family history of urolithiasis was reported in 63 and 32% respectively. Crystallization risk was detected in 74% of participants. The most common urinary abnormalities were hypocitraturia in 48% and hypercalciuria in 40%. CONCLUSIONS: The lithogenic profile revealed urinary saturation compatible with crystallization risk in 74% of the studied patients.

Malnutrición en niños menores de 5 años indígenas y no indígenas de zonas rurales, Paraguay / Malnutrition in indigenous and non-indigenous children under five years of age in rural areas, Paraguay

Los menores de cinco años de edad se afectan por la falta de alimentos adecuados mucho más rápido que a edades superiores por las demandas del crecimiento. El objetivo fue evaluar la situación nutricional de niños menores de cinco años de comunidades rurales, indígenas y no indígenas. Previo consentimiento informado de los padres o tutores, fueron evaluados 226 niños menores de cinco años de ambos sexos, 117 indígenas y 109 no indígenas según indicadores antropométricos de malnutrición por defecto y por exceso. Se aplicó una encuesta para obtener información de las características sociodemográficas y hábitos alimentarios. En niños indígenas y no indígenas la prevalencia de desnutrición global fue de 2,4 % y 2,6 %, riesgo de desnutrición 22% y 5,1%, desnutrición crónica 35,9% y 12,8%, sobrepeso 28,9% y 12,9%, respectivamente. Se observó un consumo frecuente de frutas en ambas poblaciones, seguida del consumo de proteína vegetal en población indígena y de proteína animal en los no indígenas. El 69,2% de los niños indígenas y el 3,7% de los niños no indígenas vivían en la pobreza extrema. Los principales problemas nutricionales encontrados fueron la desnutrición crónica, el riesgo de desnutrición y el sobrepeso. Los niños más fuertemente afectados son los indígenas, que sobreviven en difíciles condiciones socioeconómicas.

Children under five years of age are affected by the lack of adequate food faster thanolder individuals due to growth demands. The objective was to evaluate the nutritional situation of indigenous and non-indigenous children under five years living in rural communities. After obtaining the informed consent of their parents, 226 boys and girls under five years, 117 indigenous and 109 non-indigenous children, were evaluated using nutritional indicators of malnutrition by defect and excess. A questionnaire was applied toobtain information about social-demographic characteristics and dietary habits. Inindigenous and non-indigenous children, the prevalences of global malnutrition were 2.4% and 2.6%, malnutrition risk 22% and 5.1%, chronic malnutrition 35.9% and 12.8%,overweight 28.9% and 12.9%. Frequent consumption of fruits was observed in both populations, followed by consumption of vegetable protein in indigenous population and animal protein in non-indigenous. 69.2% of indigenous children and 3.7% of non-indigenous children living in extreme poverty. The main nutritional problems found were chronic malnutrition, malnutrition risk and overweight. The most strongly affected children were theindigenous, who survive in difficult socio-economic conditions.

Perfil de riesgo litogénico en pacientes con urolitiasis en Paraguay / Lithogenic risk in patients from Paraguay with urolithiasis

The lithogenic risk profile is a graphical representation of metabolic factors and urinary saturation involved in the stone formation with their respective critical values. Aim: To determine the lithogenic risk profile in patients with urolithiasis. Material and Methods: Personal data such as anthropometric, history of diseases and family history of urolithiasis were recorded. Different compounds acting as promoters or inhibitors of crystallization were measured in serum and urine samples, and the data obtained were used to calculate urinary saturation using Equil software. Results: We included 30 men and 43 women with a median age of 45 (34-54) years. Overweight and family history of urolithiasis was reported in 63 and 32% respectively. Crystallization risk was detected in 74% of participants. The most common urinary abnormalities were hypocitraturia in 48% and hypercalciuria in 40%. Conclusions: The lithogenic profile revealed urinary saturation compatible with crystallization risk in 74% of the studied patients.

Enteroparasitosis en niños bajo 5 años de edad, indígenas y no indígenas, de comunidades rurales del Paraguay / Enteric parasitic disease in children under 5 years of age, indigenous and non-indigenous, from rural communities in Paraguay

Background: Official figures of mortality in children under five years of age in the Americas, report that infectious and parasitic diseases caused most of the deaths. Objective: To evaluate the frequency of intestinal parasites in vulnerable children, indigenous and non-indigenous, and their socio-environmental characteristics. Patients and Methods: We evaluated 247 children under five years of age, of both sexes. Descriptive study with an analytical component, transverse cutting. Copro-parasitological examinations were carried out and semi-structured interviews to collect socio-demographic data were conducted. Results: The frequency of intestinal parasitic diseases was 56.1% and 35.5% in indigenous and non-indigenous children, respectively. In both populations, the most common pathogens were Blastocystis hominis and Giardia lamblia. Conclusion: We found a high frequency of parasitism in indigenous children at the expense of protozoa. Non-indigenous children still present the same parasitic species found in previous studies, suggesting the need to implement more control and prevention. The poor conditions in which they live favor the development of these diseases.

Introducción: Cifras oficiales de mortalidad en niños bajo 5 años de edad, en las Américas, refieren que la mayor parte de las defunciones fueron causadas por enfermedades infecciosas incluyendo las parasitarias. Objetivo: Evaluar la frecuencia de enteroparasitosis en población infantil vulnerable, indígenas y no indígenas, y sus características socio-ambientales. Pacientes y Métodos: Se evaluaron 247 niños bajo 5 años de edad, de ambos sexos. Estudio descriptivo con componente analítico, de corte transverso. Se realizaron exámenes copro-parasitológicos y se aplicaron encuestas semi-estructuradas para recoger datos socio-demográficos. Resultados: la frecuencia de enteroparasitosis en los niños indígenas fue de 56,1% y en los niños no indígenas de 35,5%. En ambas poblaciones los patógenos más frecuentes fueron Gardia lamblia y Blastocystis hominis. Conclusión: Encontramos una elevada frecuencia de parasitosis en la población infantil indígena, a expensas de los protozoarios. Los niños no indígenas siguen portando las mismas especies parasitarias encontradas en estudios anteriores, sugiriendo la necesidad de implementar un mayor control y prevención. Existen escasos estudios en nuestro país sobre parasitosis en edades tempranas y no se cuentan con datos en la niñez indígena. Las pobres condiciones en las que viven favorecen el desarrollo de estas enfermedades.

Label-free impedimetric aptasensor for ochratoxin-A detection using iridium oxide nanoparticles.

In this article, a novel aptasensor for ochratoxin A (OTA) detection based on a screen-printed carbon electrode (SPCE) modified with polythionine (PTH) and iridium oxide nanoparticles (IrO2 NPs) is presented. The electrotransducer surface is modified with an electropolymerized film of PTH followed by the assembly of IrO2 NPs on which the aminated aptamer selective to OTA is exchanged with the citrate ions surrounding IrO2 NPs via electrostatic interactions with the same surface. Electrochemical impedance spectroscopy (EIS) in the presence of the [Fe(CN)6](-3/-4) redox probe is employed to characterize each step in the aptasensor assay and also for label-free detection of OTA in a range between 0.01 and 100 nM, obtaining one of the lowest limits of detection reported so far for label-free impedimetric detection of OTA (14 pM; 5.65 ng/kg). The reported system also exhibits a high reproducibility, a good performance with a white wine sample, and an excellent specificity against another toxin present in such sample.

[Enteric parasitic disease in children under 5 years of age, indigenous and non-indigenous, from rural communities in Paraguay]. / Enteroparasitosis en niños bajo 5 años de edad, indígenas y no indígenas, de comunidades rurales del Paraguay.

BACKGROUND: Official figures of mortality in children under five years of age in the Americas, report that infectious and parasitic diseases caused most of the deaths. OBJECTIVE: To evaluate the frequency of intestinal parasites in vulnerable children, indigenous and non-indigenous, and their socio-environmental characteristics. PATIENTS AND METHODS: We evaluated 247 children under five years of age, of both sexes. Descriptive study with an analytical component, transverse cutting. Copro-parasitological examinations were carried out and semi-structured interviews to collect socio-demographic data were conducted. RESULTS: The frequency of intestinal parasitic diseases was 56.1% and 35.5% in indigenous and non-indigenous children, respectively. In both populations, the most common pathogens were Blastocystis hominis and Giardia lamblia. CONCLUSION: We found a high frequency of parasitism in indigenous children at the expense of protozoa. Non-indigenous children still present the same parasitic species found in previous studies, suggesting the need to implement more control and prevention. The poor conditions in which they live favor the development of these diseases.