Knowledge and practices about taeniasis/cysticercosis complex within the framework of the national plan for its elimination in Colombia, 2019.

The taeniasis/cysticercosis complex (TCC) belongs to the group of neglected infectious diseases with a multifactorial transmission that includes hosts such as humans and pigs of the parasitic tapeworm (Taenia solium) and environmental factors. This study represents the first phase of the National and Cross-sectoral Plan for TCC Elimination. OBJECTIVES: To obtain data about knowledge and practices in relation to the TCC from knowledge, attitudes, and practices (KAP) surveys applied in two pilot localities for building a baseline of the potential risk factors related to identification, prevention, and control of TCC in Colombia. METHODS: A descriptive cross-sectional survey from October to November in 2019 was carried out using a structured questionnaire and random sampling by single-stage conglomerates in the municipalities of Mahates, Bolívar (n = 152) (Atlantic Region) and Mercaderes, Cauca (n = 152) (Andean Region). RESULTS: Respondents in Mahates showed moderate knowledge about TCC compared to those in Mercaderes, however, risky practices were identified in both places (consumption of pork with cysts and defecation in places other than the bathroom or latrine). Deficiency in infrastructure and failure in basic services were observed as potential risk factors for TCC transmission in both municipalities. CONCLUSION: Based on the framework of the National and Cross-sectoral Plan for TCC Elimination, adequate knowledge on identification, prevention, and control of the disease must be reinforced; cultural and ecological differences should be considered when designing communication and knowledge transmission tools. We consider that major investment should be made in improving basic services and creating sustainable modernized pig farming in Mahates and Mercaderes.

The visible-light-driven photocatalytic reduction of Cr6+ using BiVO4: assessing the effect of Au deposition and the reaction parameters.

In this work, fern-leaf-like BiVO4 was used to photocatalytically reduce Cr6+ in water. Nanosized BiVO4 displayed bandgap energy and specific surface area of 2.49 eV and 5.65 m2 g-1, respectively. Metallic Au nanoparticles were deposited on the BiVO4 to increase the photocatalytic performance. To optimize the reaction conditions, the sacrificial agents methanol, ethanol, formic acid, dimethyl sulfoxide, and KI were tested, while different catalyst dosages and Au loadings were assessed. The best sacrificial agent was formic acid, which was used at an optimal concentration of 0.01 mol L-1. The complete removal of Cr6+ was attained after 90 min of visible light irradiation using a catalyst dosage of 1.5 g L-1. Depositing metallic Au nanoparticles barely improved the photocatalytic performance, thus unmodified BiVO4 was used to remove Cr6+ in tap water. The matrix effect slowed the photocatalytic process, and the complete removal of Cr6+ was achieved in 120 min. Cr3+ and Cr6+ species were precipitated on the catalyst surface at the end of the photocatalytic process; still, BiVO4 displayed high stability after three reaction cycles.

Prevalence of intestinal parasitism in preschool and school children in Colombia: Systematic review and meta-analysis.

OBJECTIVE: Intestinal parasitic infections (IPIs) are a public health challenge in developing countries such as Colombia, causing anaemia and delayed growth and development in children. We aimed to estimate the geographical and prevalence trend of IPIs in the last 30 years in school and preschool children in Colombia. METHODS: We conducted a systematic review and meta-analysis. We identified potential manuscripts through PubMed, EMBASE, Web of Science, LILACS, Scielo and Google Scholar on the IPIs prevalence in school and preschool children in Colombia. Articles included in the qualitative analysis were published between 1990 and 2020 in English or Spanish and met the inclusion criteria. Subsequently, a random-effects meta-analysis, a meta-regression and a trend analysis were performed. RESULTS: We identified 2292 articles; 109 were included in the qualitative review, and 79 articles were included in the meta-analysis. The estimated IPI prevalence was 55% (95% CI: 48-63). By age group, the prevalence in preschool children was 37% (95% CI: 26-49) and 66% (95% CI: 52-78) in schoolchildren. The prevalence by region was heterogeneous, with the Amazon being the highest (69%) and the Santanderes the lowest (28%). In the last 20 years, the prevalence of helminthiasis has decreased (from 64.66% in 1990-1995 to 22.09% in 2016-2020). CONCLUSION: The prevalence of IPIs is high (>30%) in three of the seven regions in Colombia. Biannual administration of mass deworming in schoolchildren is recommended in the Amazon region. Public policies aiming to control IPIs should be reinforced. Further prevalence studies should include Cesar, Guaviare, Vichada and Vaupés, where the epidemiology of IPIs is unknown. SUSTAINABLE DEVELOPMENT GOALS: Good health and wellbeing, clean water and sanitation, sustainable cities and communities.

Synthesis of sodium titanates and their use in the photocatalytic degradation of NO.

The synthesis and characterization of sodium titanates (ST), and their evaluation in the photocatalytic reduction of nitric oxide (NO) are described herein. The materials were synthesized by a hydrothermal route using 5 M NaOH as the mineralizer agent and a TiO2 content of 0.06 mg/mL (expressed as the mass ratio of TiO2/mL of NaOH), at 170 °C for 48 h, resulting in sodium tri- and hexa-titanates. A nanotubular morphology was observed for the ST, as proved by scanning electron microscopy (SEM); a subsequent heat-treatment at 400 °C allowed a complete transformation of sodium tri- to hexa-titanates and an increase in bandgap. The obtained ST were impregnated with Ag+ and Zn+ cations, ST-Ag and ST-Zn, respectively, to tune the materials' bandgap. XPS analysis of the ST-Ag materials showed evidence of metallic Ag, pointing to the formation of silver nanoparticles, whereas for ST-Zn oxide phases were mainly spotted. The materials were evaluated for the photocatalytic reduction of NO using a reactor fed with a continuous flow rate of NO, generated in situ at a flow of 280 mL/min using nitrogen and a 253-nm UV irradiation source. The photocatalytic tests showed that pristine ST (tri- and hexa-titanates) displayed better performance in the reduction of NO with respect to the impregnated samples (ST-Ag, ST-Zn). Maximum degradation efficiencies of 80% were achieved when 1 g of photocatalyst was used with a flow of 280 mL/min and a 253 nm UV lamp.

Intramedullary clear cell ependymoma of the lower thoracic spinal cord: report of a new case.

BACKGROUND: Clear cell ependymomas (CCEs) are a rare variant of tumors of the nervous system, the main location is the intracranial compartment. Special differential diagnosis should be done with oligodendrogliomas, neurocytoma, glioneurocytoma, astrocytoma, or metastatic renal cell carcinoma, lesions that somehow share cells with clear cytoplasm. Most of these lesions are benign but differential diagnosis is essential to decide further treatment. Few case reports of intramedullary CCEs have being published and there is no strict consensus on the diagnostic criteria. CASE DESCRIPTION: We hereby describe a new case of an intramedullary clear CCE with very few neurological symptoms, surgical treatment is satisfactory, histological and immunohistochemical analysis was confirmatory. After gross total resection and 3-year follow-up no recurrence of the lesion is evident. CONCLUSION: After this case presentation and review of the limited literature, it is evident that methodical clinical suspicion, radiological imaging combined with histological, and modern immunohistochemical techniques are essential for the diagnosis. Surgical options with gross total resection remain the cornerstone of its treatment. Neurophysiological monitoring is extremely useful to avoid postoperative morbidity.

Succinate dehydrogenase gene as a marker for studying Blastocystis genetic diversity.

Blastocystis has been reported as the most common eukaryotic microorganism residing in the intestines of both humans and animals, with a prevalence of up to 100% in some populations. Since this is a cryptic species, sequence polymorphism are the single strategy to analyses its genetic diversity, being traditionally used the analysis of ssu rRNA gene sequence to determine alleles and subtypes (STs) for this species. This multicopy gene has shown high diversity among different STs, making necessary to explore other genes to assess intraspecific diversity. This study evaluated the use of a novel genetic marker, succinate dehydrogenase (SDHA), for the typing and evaluation of the genetic diversity and genetic population structure of Blastocystis. In total, 375 human fecal samples were collected and subjected to PCR, subtyped using the ssu rRNA marker, and then the SDHA gene was amplified via PCR for 117 samples. We found some incongruences between tree topologies for both molecular markers. However, the clustering by ST previously established for Blastocystis was congruent in the concatenated sequence. SDHA showed lower reticulation (The origination of a lineage through the partial merging of two ancestor lineages) signals and better intra ST clustering ability. Clusters with geographical associations were observed intra ST. The genetic diversity was lower in the marker evaluated compared to that of the ssu rRNA gene (nucleotide diversity = 0.03344 and 0.16986, respectively) and the sequences analyzed showed population expansion with genetic differentiation principally among STs. The ssu rRNA gene was useful to explore interspecific diversity but together with the SDHA gene the resolution power to evaluate intra ST diversity was higher. These results showed the potential of the SDHA marker for studying the intra ST genetic diversity of Blastocystis related with geographical location and the inter ST diversity using the concatenated sequences.

The genetic characterization of fall armyworm populations in Ecuador and its implications to migration and pest management in the northern regions of South America.

The fall armyworm (Spodoptera frugiperda) is a moth pest native to the Western Hemisphere that has recently become a global problem, invading Africa, Asia, and Australia. The species has a broad host range, long-distance migration capability, and a propensity for the generation of pesticide resistance traits that make it a formidable invasive threat and a difficult pest to control. While fall armyworm migration has been extensively studied in North America, where annual migrations of thousands of kilometers are the norm, migration patterns in South America are less understood. As a first step to address this issue we have been genetically characterizing fall armyworm populations in Ecuador, a country in the northern portion of South America that has not been extensively surveyed for this pest. These studies confirm and extend past findings indicating similarities in the fall armyworm populations from Ecuador, Trinidad-Tobago, Peru, and Bolivia that suggest substantial migratory interactions. Specifically, we found that populations throughout Ecuador are genetically homogeneous, indicating that the Andes mountain range is not a long-term barrier to fall armyworm migration. Quantification of genetic variation in an intron sequence describe patterns of similarity between fall armyworm from different locations in South America with implications for how migration might be occurring. In addition, we unexpectedly found these observations only apply to one subset of fall armyworm (the C-strain), as the other group (R-strain) was not present in Ecuador. The results suggest differences in migration behavior between fall armyworm groups in South America that appear to be related to differences in host plant preferences.

Development of a Multilocus Sequence Typing Scheme for Giardia intestinalis.

Giardia intestinalis is an intestinal protozoan most commonly found in humans. It has been grouped into 8 assemblages (A-H). Markers such as the glutamate dehydrogenase gene, triose phosphate isomerase and beta-giardin (ß-giardin) have been widely used for genotyping. In addition, different genetic targets have been proposed as a valuable alternative to assess diversity and genetics of this microorganism. Thus, our objective was to evaluate new markers for the study of the diversity and intra-taxa genetic structure of G. intestinalis in silico and in DNA obtained from stool samples. We analysed nine constitutive genes in 80 complete genome sequences and in a group of 24 stool samples from Colombia. Allelic diversity was evaluated by locus and for the concatenated sequence of nine loci that could discriminate up to 53 alleles. Phylogenetic reconstructions allowed us to identify AI, AII and B assemblages. We found evidence of intra- and inter-assemblage recombination events. Population structure analysis showed genetic differentiation among the assemblages analysed.

Molecular and descriptive epidemiology of intestinal protozoan parasites of children and their pets in Cauca, Colombia: a cross-sectional study.

BACKGROUND: Parasitic infections, particularly those caused by protozoa, represent a considerable public health problem in developing countries. Blastocystis, Giardia duodenalis, Cryptosporidium spp. and the Entamoeba complex (Entamoeba histolytica, Entamoeba dispar and Entamoeba moshkovskii) are the most common etiological causes of intestinal parasitic infections. METHODS: We carried out a descriptive cross-sectional study in school-age children attending a daycare institution in commune eight of Popayán, Cauca (Southwest Colombia). A total of 266 fecal samples were collected (258 from children and eight from pets). Blastocystis, G. duodenalis, Cryptosporidium spp. and the Entamoeba complex were identified by microscopy, quantitative real-time PCR (qPCR) and conventional PCR. The concordance of qPCR and microscopy was assessed using the Kappa index. Molecular characterization was conducted to identify Blastocystis subtypes (18S), G. duodenalis assemblages (tpi and gdh) and Cryptosporidium species/subtypes (18S and GP60). Potential associations between intestinal parasitism and sociodemographic factors were examined using bivariate analyses. RESULTS: A total of 258 fecal samples from children were analyzed by microscopy and 255 samples were analyzed by qPCR. The prevalence of Blastocystis was between 25.19% (microscopy) and 39.22% (qPCR), that of G. duodenalis was between 8.14% (microscopy) and 10.59% (qPCR), that of Cryptosporidium spp. was estimated at 9.8% (qPCR), and that of the Entamoeba complex was between 0.39% (conventional PCR) and 0.78% (microscopy). The concordance between microscopy and qPCR was very low. Blastocystis ST1 (alleles 4, 8, and 80), ST2 (alleles 11, 12, and 15), ST3 (alleles 31, 34, 36, 38,57, and 151), and ST4 (alleles 42 and 91), G. duodenalis assemblages AII, BIII, BIV and D, C. parvum subtype IIa and C. hominis subtype IbA9G3R2 were identified. The only identified member of the Entamoeba complex corresponded to E. histolytica. No statistically significant association was identified between parasitic infection and any sociodemographic variable. CONCLUSION: This study revealed the usefulness of molecular methods to depict the transmission dynamics of parasitic protozoa in southwest Colombia. The presence of some of these protozoa in domestic animals may be involved in their transmission.

Molecular detection and genotyping of pathogenic protozoan parasites in raw and treated water samples from southwest Colombia.

BACKGROUND: Protozoan parasites such as Giardia duodenalis, Cryptosporidium spp., Cyclospora cayetanensis, Toxoplasma gondii and Entamoeba histolytica represent a great challenge to the systems producing water for human consumption because their cystic forms are persistent in the environment and resist to the disinfection methods conventionally used for their control. In this study, we investigated the presence of these protozoan pathogens in both raw and treated water samples used for the production of drinking water in Nariño Department, southwest Colombia. We collected 110 water samples (10 lof each sample) and analyzed them with real-time PCR (qPCR). qPCR-positive samples were genotyped with PCR and DNA sequencing. RESULTS: Giardia duodenalis was detected in 35/110 (31.8%) of the samples and Cryptosporidium spp. in 9/110 (8.2%) of the samples; no sample was positive for T. gondii, E. histolytica or C. cayetanensis. Giardia duodenalis was detected in samples of both raw water (Drinking Water Treatment Plants (DWTP): 47.83%;Drinking Water Rural Plants (DWRP): 18.42%) and water collected either after conventional physicochemical treatment (26.09%) or after disinfection by chlorine (50%), whereas Cryptosporidium spp. were only detected in raw waters (DWTP: 17.39%; DWRP: 13.16%). The two pathogens were detected in both types of treatment plants supplying water to urban areas and to rural zones. Analysis of gdh and tpi markers identified assemblages AI, AII and H of G. duodenalis, while analysis of the small subunit rRNA and gp60 markers of Cryptosporidium-positive samples identified C. parvum (Subtype IIcA5G3c), C. galli, C. molnari, Cryptosporidium sp. genotype II of bats and Cryptosporidium sp. genotype VIII of birds. CONCLUSIONS: The results obtained demonstrate the presence of protozoan parasites in the water of the study region, and the need to improve the surveillance systems for these pathogens and identify the corresponding sources of contamination.

Elimination of onchocerciasis from Colombia: first proof of concept of river blindness elimination in the world.

BACKGROUND: Onchocerciasis is a chronic parasitic infection originally endemic in 13 discrete regional foci distributed among six countries of Latin America (Brazil, Colombia, Ecuador, Guatemala, Mexico and Venezuela). In Colombia, this disease was discovered in 1965 in the Pacific Coast of the country. The National Onchocerciasis Elimination Program was established in 1993 with the aim of eliminating disease morbidity and infection transmission. In 2013, the World Health Organization (WHO) verified Colombia as free of onchocerciasis, becoming the first country in the world to reach such a goal. This report provides the empirical evidence of the elimination of Onchocerca volvulus transmission by Simulium exiguum (s.l.) after 12 years of 6-monthly mass drug administration of Mectizan® (ivermectin) to all the eligible residents living in this endemic area. METHODS: From 1996 onwards, a biannual community-based mass ivermectin administration programme was implemented, complemented by health education and community participation. In-depth parasitological, serological and entomological surveys were conducted periodically between 1998 and 2007 to evaluate the impact of ivermectin treatment according to the 2001 WHO guidelines. When the interruption of parasite transmission was demonstrated, the drug distribution ceased and a three-year post-treatment surveillance (PTS) period (2008-2010) was initiated. RESULTS: After 23 rounds of treatment, parasitological and ophthalmological assessments showed absence of microfilariae in skin and anterior chamber of the eyes. Serological tests proved lack of antibodies against O. volvulus in children under 10 years-old. A total of 10,500 S. exiguum flies tested by PCR had no L3 infection (infectivity rate = 0.0095%; 95% CI: 0.0029-0.049) during 2004, indicating interruption of parasite transmission. However, biannual ivermectin treatments continued until 2007 followed by a 3-year PTS period at the end of which 13,481 flies were analyzed and no infective flies were found (infectivity rate = 0%; 95% CI: 0.0-0.014). CONCLUSIONS: These results fulfilled the WHO criteria for onchocerciasis elimination. Consequently, in 2013 Colombia was verified as free of onchocerciasis, demonstrating that elimination of this neglected tropical disease is an achievable goal and paving the way for an elimination agenda to be followed by other endemic countries in Latin America and Africa.

"Omics" Education in Dietetic Curricula: A Comparison between Two Institutions in the USA and Mexico.

BACKGROUND/AIMS: The completion of sequencing of the human genome and a better understanding of epigenomic regulation of gene expression have opened the possibility of personalized nutrition in the near future. This has also created an immediate need for trained personnel qualified to administer personalized nutrition education. Of all the allied healthcare personnel, dietitians are the most likely to undertake this role. However, dietitians and dietetic students are still deficient in their knowledge of nutrigenomics and other "omics" technologies. Therefore, with the eventual goal of dietetic curriculum reorganization, the International Society of Nutrigenetics/Nutrigenomics (ISNN) has set out to evaluate nutrigenomic knowledge among dietetic students from different countries. In this study, we compared nutrition and dietetic students from Texas Woman's University (TWU) and the Universidad Autónoma de Nuevo León (UANL) for their perceived need for, interest in, and knowledge of different topics within nutritional genomics. METHODS: Students from both universities were sent an e-mail link to the survey which was located at psychdata.com. One hundred twenty-seven students completed the survey. The survey assessed the students' knowledge of, perceived need for, and interest in different omics technologies, as well as their basic knowledge of basic nutrition and genetic topics. Differences were assessed using the χ2 test for homogeneity and Fisher's exact test. RESULTS: Students from TWU and UANL exhibited differences in their knowledge, desire to learn more, and perceived need for omics science in some but not all categories. CONCLUSIONS: Undergraduate nutrition students from both the USA and Mexico lack a high level of knowledge in different omics topics but recognize the role that omics will play in their future as dietitians. There were differences between the 2 universities in terms of the desire to learn more about different omics technologies and to take more classes covering different topics with nutritional genomic components. In order to make personalized nutrition a reality, future dietitians will need to become fluent in different omics technologies.

[Profiles of intestinal polyparasitism in a community of the Colombian Amazon region].

INTRODUCTION: Intestinal parasite infections and polyparasitism are highly prevalent in the most vulnerable populations of developing countries due to environmental, biological and social determinants common in the transmission of parasites. Children between 1 and 15 years of age are the most affected population. OBJECTIVE: To describe the prevalence and profiles of intestinal polyparasitism in 1 to 15 year-old children from native communities in the Colombian Amazon region. MATERIALS AND METHODS: We used a non-probability sampling of 300 children between 1 and 15 years of age from several rural settlements and the main urban area of Puerto Nariño, Amazonas, Colombia, who participated voluntarily in the study. We obtained fecal samples that were analyzed by the direct method (0.85% saline solution-lugol) and the Kato-Katz technique. The most prevalent polyparasitism profiles were identified using Cohen's kappa coefficient with a 95% confidence interval. RESULTS: The prevalence of polyparasitism, defined as the presence of at least two intestinal pathogenic parasites, was 84% (95 % CI: 79.35-87.96). Polyparasitism by two or three of the following parasites: Ascaris lumbricoides, Trichuris trichiura, Blastocystis sp., Ancylostoma duodenale and Necator americanus from the Ancylostomatidae family, and Entamoeba histolytica, E. dispar and E. moshkovskii of the Entamoeba complex, had the highest prevalence. CONCLUSION: Several intestinal polyparasitism profiles were found, although in most cases fewer than six parasites were involved. Better prevalence estimations and identification of determinant factors will allow to priorize and direct resources to control these infections.

Removal of arsenic III and V from laboratory solutions and contaminated groundwater by metallurgical slag through anion-induced precipitation.

Metallurgical slag was used for the simultaneous removal of high concentrations of arsenite and arsenate from laboratory solutions and severely contaminated groundwater. Apart from demonstrating the high efficiency of arsenic removal in presence of competing species, the work aims to explore the physicochemical mechanisms of the process by means of microscopy observation and a detailed statistical analysis of existing kinetic and isotherm equations. Fitting was performed by non-linear least squares using weighted residuals; ANOVA and bootstrap methods were used to compare the models. Literature suggests that the metal oxides in the slag are efficient adsorbents of As(III) and (V). However, the low surface area of the slag precludes adsorption; SEM observation provide evidence of a mechanism of co-precipitation of lixiviated cations with contaminant anions. The reaction kinetics provide essential information on the interaction between the contaminants, particularly on the common ion effect in groundwater. The Fritz-Schlünder isotherm allows modelling the saturation effect at low slag doses. The efficiency of the process is demonstrated by an arsenic removal of 99% in groundwater using 4-g slag/L, resulting in an effluent with 0.01 mg As/L, which is below Mexican and international standards for drinking water.

Perfiles de poliparasitismo intestinal en una comunidad de la Amazonia colombiana / Profiles of intestinal polyparasitism in a community of the Colombian Amazon region

Resumen Introducción. Las infecciones parasitarias y el poliparasitismo intestinal son muy prevalentes en las poblaciones más vulnerables de los países en desarrollo debido a la existencia de factores ambientales, biológicos y sociales determinantes en la transmisión de parásitos. La población entre uno y 15 años de edad es la más afectada por dicha situación. Objetivo. Describir las prevalencias y los perfiles del poliparasitismo intestinal en la población de uno a 15 años de edad de comunidades indígenas de la Amazonia colombiana. Materiales y métodos. Se hizo un muestreo no probabilístico de 300 niños entre uno y 15 años de edad, procedentes de varios asentamientos rurales y de la cabecera urbana de Puerto Nariño, Amazonas, quienes participaron voluntariamente en el estudio. Las muestras de materia fecal se analizaron mediante el método directo (solución salina al 0,85 % y lugol) y la técnica de Kato-Katz. Se determinaron los perfiles más prevalentes de poliparasitismo intestinal con el coeficiente kappa de Cohen y un intervalo de confianza de 95 %. Resultados. La prevalencia de poliparasitismo, definida como la presencia de, por lo menos, dos parásitos intestinales patógenos, fue de 84 % (IC95 %: 79,35-87,96). Los casos con presencia de dos o tres agentes incluyeron los parásitos Ascaris lumbricoides, Trichuris trichiura, Blastocystis sp., los ancilostomídeos Ancylostoma duodenale yNecator americanus, así como Entamoeba histolytica,E. dispar y E. moshkovskii del complejo Entamoeba, y fueron los de mayor prevalencia. Conclusión. Se encontraron varios perfiles de poliparasitismo intestinal, aunque la mayoría de los casos involucraron menos de seis especies. Una mejor estimación de la prevalencia y los factores determinantes del poliparasitismo intestinal permitirían priorizar y orientar los recursos para su control.

Abstract Introduction: Intestinal parasite infections and polyparasitism are highly prevalent in the most vulnerable populations of developing countries due to environmental, biological and social determinants common in the transmission of parasites. Children between 1 and 15 years of age are the most affected population. Objective: To describe the prevalence and profiles of intestinal polyparasitism in 1 to 15 year-old children from native communities in the Colombian Amazon region. Materials and methods: We used a non-probability sampling of 300 children between 1 and 15 years of age from several rural settlements and the main urban area of Puerto Nariño, Amazonas, Colombia, who participated voluntarily in the study. We obtained fecal samples that were analyzed by the direct method (0.85% saline solution-lugol) and the Kato-Katz technique. The most prevalent polyparasitism profiles were identified using Cohen's kappa coefficient with a 95% confidence interval. Results: The prevalence of polyparasitism, defined as the presence of at least two intestinal pathogenic parasites, was 84% (95 % CI: 79.35-87.96). Polyparasitism by two or three of the following parasites: Ascaris lumbricoides,Trichuris trichiura, Blastocystis sp., Ancylostoma duodenale and Necator americanus from the Ancylostomatidae family, and Entamoeba histolytica,E. dispar and E. moshkovskii of the Entamoeba complex, had the highest prevalence. Conclusion: Several intestinal polyparasitism profiles were found, although in most cases fewer than six parasites were involved. Better prevalence estimations and identification of determinant factors will allow to priorize and direct resources to control these infections.

Combination of five diagnostic tests to estimate the prevalence of hookworm infection among school-aged children from a rural area of colombia.

BACKGROUND: Public health programs for the control of soil-transmitted helminthiases require valid diagnostic tests for surveillance and parasitic control evaluation. However, there is currently no agreement about what test should be used as a gold standard for the diagnosis of hookworm infection. Still, in presence of concurrent data for multiple tests it is possible to use statistical models to estimate measures of test performance and prevalence. The aim of this study was to estimate the diagnostic accuracy of five parallel tests (direct microscopic examination, Kato-Katz, Harada-Mori, modified Ritchie-Frick, and culture in agar plate) to detect hookworm infections in a sample of school-aged children from a rural area in Colombia. METHODS AND RESULTS: We used both, a frequentist approach, and Bayesian latent class models to estimate the sensitivity and specificity of five tests for hookworm detection, and to estimate the prevalence of hookworm infection in absence of a Gold Standard. The Kato-Katz and agar plate methods had an overall agreement of 95% and kappa coefficient of 0.76. Different models estimated a sensitivity between 76% and 92% for the agar plate technique, and 52% to 87% for the Kato-Katz technique. The other tests had lower sensitivity. All tests had specificity between 95% and 98%. The prevalence estimated by the Kato-Katz and Agar plate methods for different subpopulations varied between 10% and 14%, and was consistent with the prevalence estimated from the combination of all tests. The Harada-Mori, Ritchie-Frick and direct examination techniques resulted in lower and disparate prevalence estimates. Bayesian approaches assuming imperfect specificity resulted in lower prevalence estimates than the frequentist approach.

Preservación de huevos de Necator americanus con acetato de sodio-ácido acético-formalina (SAF). Estudio de caso / Preservation of Necator americanus eggs with sodium acetate-acetic acid-formalin(SAF). Case study

Resumen Introducción. La técnica de Kato Katz es el método recomendado para realizar el recuento de huevos en materia fecal y determinar la intensidad parasitaria por helmintos. La calidad de los resultados se ve afectada por la tardanza en el procesamiento de la muestra, por lo que se requiere de preservantes que faciliten la lectura posterior a las 24 horas de recolección de la muestra. Objetivo. Demostrar validez de la solución con acetato de sodio-ácido acético-formalina (SAF) como preservante de huevos de Necator americanus por medio del estudio de un caso clinico. Materiales y métodos. Descripción de caso clínico con diagnóstico de parásitos intestinales por coprológico, intensidad de la infección por la técnica de Kato Katz, evaluación de la presencia de huevos N. americanus por la técnica de Kato Katz durante 10 meses en muestra preservada en SAF y determinación de especie de Uncinaria sp. por qPCR. Resultados. Los huevos de N. americanus se conservan de manera adecuada en morfología durante los primeros cinco meses. Conclusiones. A fin de ejecutar la técnica de Kato Katz, la fijación con SAF demostró ser adecuada para el mantenimiento de la intensidad parasitaria y morfología de los huevos de N. americanus en un período de hasta cinco meses.

Abstract Introduction: The Kato Katz technique is the recommended method for fecal egg counts and determining the intensity of parasitic helminths. The quality of the results is affected by the delay in the analysis of the sample. Therefore, fixatives are necessary to make the reading easier 24 hours after sample collection. Objective: To prove the usefulness of sodium acetate-acetic acid-formalin (SAF) solution as a fixative for Necator americanus eggs by means of a clinical case study. Materials and methods: Clinical case description and intestinal parasites diagnosis by direct stool microscopic analysis and parasite infection intensity by means of the Kato Katz technique. N. americanus eggs were detected by Kato Katz method for 10 months on a SAF-fixed stool sample. Identification of Uncinaria sp. by qPCR. Results: N. americanus eggs are adequately preserved in SAF during the first five months. Conclusions: SAF fixative is suitable for Kato Katz method and proved to be capable of maintaining parasite intensity and N. americanus egg morphology over a period of up to five months.

Molecular Epidemiology of Giardia, Blastocystis and Cryptosporidium among Indigenous Children from the Colombian Amazon Basin.

The incidence and prevalence of intestinal parasites in children is most likely due to lack of natural or acquired resistance and differences in behavior and habits closely related to environmental and socioeconomic determinants. The most important protozoa that parasitize humans are Giardia, Entamoeba, Blastocystis, and Cryptosporidium. These parasites present wide intraspecific genetic diversity and subsequently classified into assemblages and subtypes. The Amazon basin is the largest in the world and is the fifth freshwater reserve on the planet. Contradictorily, people living in these areas (Indigenous populations) have poor quality of life, which favors the infection of diseases of fecal-oral transmission. The aim of this work was to unravel the molecular epidemiology of Giardia, Blastocystis and Cryptosporidium across four communities (Puerto Nariño, San Juan del Soco, Villa Andrea and Nuevo Paraíso). We obtained 284 fecal samples from children under 15 years old that were analyzed by direct microscopy (261 samples) and Real Time PCR (qPCR) (284 samples). The positive samples for these protozoa were further characterized by several molecular markers to depict assemblages and subtypes. We observed a frequency of Giardia infection by microscopy of 23.7% (62 samples) and by qPCR of 64.8% (184 samples); for Blastocystis by microscopy of 35.2% (92 samples) and by qPCR of 88.7% (252 samples) and for Cryptosporidium only 1.9% (5 samples) were positive by microscopy and qPCR 1.8% (5 samples). Regarding the Giardia assemblages, using the glutamate dehydrogenase (gdh) marker we observed AI, BIII and BIV assemblages and when using triose phosphate isomerase (tpi) we observed assemblages AI, AII, BIII and BIV. In contrast, Blastocystis STs detected were 1, 2, 3, 4, and 6. Lastly, the species C. viatorum, C. hominis (with the subtypes IdA19 and IaA12R8) and C. parvum (with the subtype IIcA5G3c) were identified. We observed a high profile of zoonotic transmission regarding the Giardia assemblages and Blastocystis STs/alleles. Also, we highlight the elevated frequency of infection by these two protozoans suggesting an active transmission in the area. Our findings reinforces the need to deploy better epidemiological surveillance systems for enteric pathogens in the area.

Clinical and Parasitological Features of Patients with American Cutaneous Leishmaniasis that Did Not Respond to Treatment with Meglumine Antimoniate.

BACKGROUND: American cutaneous leishmaniasis (ACL) is a complicated disease producing about 67.000 new cases per year. The severity of the disease depends on the parasite species; however in the vast majority of cases species confirmation is not feasible. WHO suggestion for ACL produced by Leishmania braziliensis, as first line treatment, are pentavalent antimonial derivatives (Glucantime or Sodium Stibogluconate) under systemic administration. According to different authors, pentavalent antimonial derivatives as treatment for ACL show a healing rate of about 75% and reasons for treatment failure are not well known. METHODS: In order to characterise the clinical and parasitological features of patients with ACL that did not respond to Glucantime, a cross-sectional observational study was carried out in a cohort of 43 patients recruited in three of the Colombian Army National reference centers for complicated ACL. Clinical and paraclinical examination, and epidemiological and geographic information were recorded for each patient. Parasitological, histopathological and PCR infection confirmation were performed. Glucantime IC50 and in vitro infectivity for the isolated parasites were estimated. RESULTS: Predominant infecting Leishmania species corresponds to L. braziliensis (95.4%) and 35% of the parasites isolated showed a significant decrease in in vitro Glucanatime susceptibility associated with previous administration of the medicament. Lesion size and in vitro infectivity of the parasite are negatively correlated with decline in Glucantime susceptibility (Spearman: r = (-)0,548 and r = (-)0,726; respectively). CONCLUSION: A negative correlation between lesion size and parasite resistance is documented. L. braziliensis was found as the main parasite species associated to lesion of patients that underwent treatment failure or relapse. The indication of a second round of treatment in therapeutic failure of ACL, produced by L. braziliensis, with pentavalent antimonial derivatives is discussable.

Geographic distribution of human Blastocystis subtypes in South America.

Blastocystis is a cosmopolitan enteric protist colonizing probably more than 1 billion people. This protozoan exhibits genetic diversity and is subdivided into subtypes (STs). The aim of this study was to determine the distribution of Blastocystis STs in symptomatic and asymptomatic human samples from different countries of South America. A total of 346 fecal samples were genotyped by SSU rDNA showing ST1 (28.3%), ST2 (22.2%), ST3 (36.7%), ST4 (2%), ST5 (2.3%), ST6 (2%), ST7 (2.3%), ST8 (0.6%), ST12 (0.9%) and a novel ST (2.7%). These findings update the epidemiology of Blastocystis in South America and expand our knowledge of the phylogeographic differences exhibited by this stramenopile.