Blastocistosis y urticaria, una asociación poco conocida

Introducción: Globalmente, Blastocystis spp. es el protozoo más frecuentemente encontrado en las heces de humanos y otros animales. En Cuba, la Encuesta Nacional de Parasitismo Intestinal de 2009 demostró que la infección por Blastocystis spp. era la parasitosis más prevalente. La asociación entre blastocistosis y urticaria ha sido reportada de manera creciente en la literatura internacional. Esa asociación, poco conocida entre los profesionales de la salud cubanos, no ha sido estudiada en nuestro país. Objetivos: Describir la asociación entre blastocistosis y urticaria. Métodos: Mediante búsqueda electrónica en las bases de datos PubMed, Medline y Google Scholar, se realizó una revisión de los artículos publicados durante el período 2003-2023 sobre las evidencias y los mecanismos de asociación entre blastocistosis y urticaria. Puntualmente, también fueron consultados monografías y artículos originales fechados con anterioridad al intervalo mencionado. Resultados: Se expone y analiza, con un enfoque académico y asistencial, la información actualizada sobre los temas seleccionados. Conclusiones: Evidencias epidemiológicas, clínicas y terapéuticas demuestran asociación entre la infección por Blastocystis spp. y el desarrollo de urticaria. Trabajos recientes, insuficientes aún, describen los mecanismos que explicarían esa asociación. Algunos de esos mecanismos son similares a los relacionados con el desarrollo de lesiones urticarianas en el curso de otras infecciones parasitarias. Por ese motivo, el diagnóstico y tratamiento de lesiones urticarianas de posibles etiologías parasitarias debe hacerse desde un enfoque que tenga en cuenta no solo las condiciones socioeconómicas y sanitarias comunes que las propician, sino también el posible efecto potenciador de los mecanismos de las de una causa sobre los de otras.

Introduction: Globally, Blastocystis spp. is the protozoan most frequently found in the feces of humans and other animals. In Cuba, the 2009 National Survey of Intestinal Parasitism demonstrated that infection by Blastocystis spp. was the most prevalent parasitism. The association between blastocystosis and urticaria has been increasingly reported in the international literature. This association, little known among Cuban health professionals, has not been studied in our country. Objectives: To describe the mechanisms of the association between blastocystosis and urticaria. Methods: Through an electronic search in PubMed, Medline and Google Scholar databases, a review was carried out of the articles published during the period 2003-2023 on the evidence and mechanisms of association between blastocystosis and urticaria. Purposely, monographs and original articles dated prior to the aforementioned interval were also consulted. Results: Updated information on the selected topics is presented and analyzed with an academic and healthcare approach. Conclusions: Epidemiological, clinical and therapeutic evidence demonstrates an association between infection by Blastocystis spp. and the development of urticaria. Recent works, still insufficient, describes the mechanisms that would explain this association. Some of these mechanisms are similar to those related to the development of urticarial lesions during other parasitic infections. For this reason, the diagnosis and treatment of urticarial lesions of possible parasitic etiologies must be done from an approach that takes into account not only the common socioeconomic and health conditions that promote them, but also the possible enhancing effect of the mechanisms of those of a cause on those of others.

Dinámica de la evolución de las formas de Blastocystis spp. en un medio de cultivo simple / Dynamics of the evolution of the forms of Blastocystis spp. in a simple culture medium

Resumen Blastocystis spp. es un parásito muy frecuente en materia fecal humana, pero la naturaleza polimórfica y el número de Blastocystis en la muestra pueden complicar su detección por microscopía. El objetivo del trabajo fue describir la dinámica de los morfotipos de Blastocystis a corto plazo en un medio de cultivo simple y determinar su aplicabilidad para utilizarlo como complemento del análisis coproparasitológico y para estudios morfológicos, bioquímicos y moleculares del parásito. Se sembraron 10 muestras de materia fecal con Blastocystis en un medio Pavlova adaptado, se examinaron diariamente por examen microscópico durante 6 días y se registraron las formas y el recuento. El desarrollo fue regular y abundante y las formas fueron de tamaños variables y claramente identificables. El cultivo ensayado puede ser útil para la detección de Blastocystis cuando existan dudas diagnósticas por microscopía, para estudios de sensibilidad y especificidad diagnóstica o cuando se requiera aumentar la carga para realizar otros estudios.

Abstract Blastocystis spp. is a very frequent parasite in human fecal matter, but the polymorphic nature and the number of Blastocystis in a sample can complicate its detection by microscopy. The objective of the present work was to describe the dynamics of Blastocystis morphotypes in the short term in a simple culture medium and to determine its applicability to use it as a complement to coproparasitological analysis and for morphological, biochemical and molecular studies of the parasite. Ten stool samples with Blastocystis were cultured in an adapted Pavlova medium and examined during 6 days by microscopy to record the forms and the count. The development was regular and abundant and the shapes were of variable sizes and clearly identifiable. The tested culture could be used for the detection of Blastocystis when microscopic diagnosis is dubious, for studies of diagnostic sensitivity and specificity or when it is necessary to increase the load to perform other studies.

Resumo Blastocystis spp. é um parasita muito frequente nas fezes humanas, mas a natureza polimórfica e o número de Blastocystis na amostra podem complicar a sua detecção através do microscópio. O objetivo do trabalho foi descrever a dinâmica dos morfotipos de Blastocystis no curto prazo em um meio de cultura simples e determinar sua aplicabilidade para ser utilizado como complemento da análise coproparasitológica e para estudos morfológicos, bioquímicos e moleculares do parasita. Foram semeadas dez amostras de fezes com Blastocystis em um meio Pavlova adaptado e examinadas diariamente através de exame microscópico durante 6 dias, registrando as formas e fazendo recontagem. O desenvolvimento foi regular e abundante e as formas foram de tamanhos variáveis e claramente identificáveis. A cultura testada pode ser útil para a detecção de Blastocystis quando houver dúvidas diagnósticas por microscopia; para estudos de sensibilidade e especificidade diagnóstica ou quando for necessário aumentar a carga para a realização de outros estudos.

Standardization of molecular techniques for the detection and characterization of intestinal protozoa and other pathogens in humans.

Background: The intrinsic sensitivity limitations of basic parasitological methods, along with the particular biological characteristics of parasites, make these methods ineffective to differentiate morphologically indistinguishable species. Molecular detection and characterization techniques could be used to overcome these problems. The purpose of this work was to standardize molecular polymerase chain reaction (PCR) techniques, described in the literature, for the detection and molecular characterization of intestinal protozoa and other pathogens in humans. Methods: DNA was extracted from human or animal feces, previously washed or cultured in Boeck Drbohlav's Modified Medium. DNA extraction was performed with Machery-Nagel extraction kits. The standardization of the PCR, nested-PCR or RFLP techniques was carried out according to the literature. For each molecular technique performed, the sensitivity of the test was determined based on the minimun quantity required of DNA (sensitivity A) and the minimum quantity of life forms that the test detected (sensitivity B). Results: Sensitivity A was 10 fg for G. duodenalis, 12.5 pg for Entamoeba histolytica or Entamoeba dispar, 50 fg for Cryptosporidium spp., 225 pg for Cyclospora spp. and 800 fg or 8 fg for Blastocystis spp. after performing a 1780 bp PCR or 310 bp nested PCR, respectively. The sensitivity B was 100 cysts for G. duodenalis, 500 cysts for E. histolytica or E. dispar, 1000 oocysts for Cyclospora spp. and 3600 or four vegetatives forms for PCR or nested PCR of Blastocystis spp., respectively. Conclusions: The molecular detection of protozoa and chromist was achieved and the molecular characterization allowed the genotyping of some of the parasites such as Giardia duodenalis, Cryptosporidium spp., and Blastocystis spp. This study summarizes the molecular techniques for epidemiological studies in humans and animals, and helps in the investigation of their transmission sources in countries where intestinal parasites are a public health problem.

Standardization of molecular techniques for the detection and characterization of intestinal protozoa and other pathogens in humans

Background: The intrinsic sensitivity limitations of basic parasitological methods, along with the particular biological characteristics of parasites, make these methods ineffective to differentiate morphologically indistinguishable species. Molecular detection and characterization techniques could be used to overcome these problems. The purpose of this work was to standardize molecular polymerase chain reaction (PCR) techniques, described in the literature, for the detection and molecular characterization of intestinal protozoa and other pathogens in humans. Methods: DNA was extracted from human or animal feces, previously washed or cultured in Boeck Drbohlav's Modified Medium. DNA extraction was performed with Machery-Nagel extraction kits. The standardization of the PCR, nested-PCR or RFLP techniques was carried out according to the literature. For each molecular technique performed, the sensitivity of the test was determined based on the minimun quantity required of DNA (sensitivity A) and the minimum quantity of life forms that the test detected (sensitivity B). Results: Sensitivity A was 10 fg for G. duodenalis, 12.5 pg for Entamoeba histolytica or Entamoeba dispar, 50 fg for Cryptosporidium spp., 225 pg for Cyclospora spp. and 800 fg or 8 fg for Blastocystis spp. after performing a 1780 bp PCR or 310 bp nested PCR, respectively. The sensitivity B was 100 cysts for G. duodenalis, 500 cysts for E. histolytica or E. dispar, 1000 oocysts for Cyclospora spp. and 3600 or four vegetatives forms for PCR or nested PCR of Blastocystis spp., respectively. Conclusions: The molecular detection of protozoa and chromist was achieved and the molecular characterization allowed the genotyping of some of the parasites such as Giardia duodenalis, Cryptosporidium spp., and Blastocystis spp. This study summarizes the molecular techniques for epidemiological studies in humans and animals, and helps in the investigation of their transmission sources in countries where intestinal parasites are a public health problem.(AU)

Prevalence of intestinal parasites and molecular characterization of Giardia intestinalis, Blastocystis spp. and Entamoeba histolytica in the village of Fortín Mbororé (Puerto Iguazú, Misiones, Argentina).

BACKGROUND: Intestinal parasites (IPs) are widely distributed worldwide and are one of the major contributors to gastrointestinal disease. Their prevalence is associated with poor access to water, sanitation and hygiene (WASH). The objective of this study was to identify the prevalence of IPs, including soil-transmitted helminths (STH), and their relation to socioeconomic characteristics, as well as a first approach to molecularly characterize the types of Giardia intestinalis, Blastocystis spp. and Entamoeba histolytica present in an indigenous community from Puerto Iguazú, Misiones, Argentina. METHODS: A cross-sectional study was conducted in the rural settlement of Fortin Mbororé between January and March 2018. Socioeconomic variables, household characteristics, and stool and blood samples were collected. Standard coprological techniques were used to analyze stool samples, and a complete hemogram was performed on the blood samples. Giardia intestinalis microscopy-positive samples were genetically typed by the ß-giardin (bg) gene. Molecular identification of Blastocystis spp. subtypes and E. histolytica were carried out by amplification and sequencing of a partial fragment of the small subunit ribosomal RNA gene (SSU rDNA). RESULTS: The overall prevalence of IPs was 92.7%, with 72.0% specifically for hookworm. IPs were significantly more prevalent in preschool- and school-age children (P < 0.05). No formal education (P = 0.035), the presence of unimproved floors (P = 0.001) and overcrowding (P = 0.005) were significantly associated with IP infection. Hookworm was associated with anemia (P = 0.019). Molecular characterization revealed the presence of E. histolytica sub-assemblages AII (12.5%), AIII (87.5%) and BIV (100%); one case of sub-assemblage D for G. intestinalis; and the presence of subtypes ST1 (14.8%), ST2 (14.8%) and ST3 (70.4%) of Blastocystis spp. CONCLUSIONS: Protozoans detected in this study are transmitted mainly through water contaminated with fecal matter, evidencing the need to improve the quality of water and sanitation for the inhabitants of Fortín Mbororé. Molecular characterization showed that domestic animals can be implicated in the zoonotic transmission of G. intestinalis and Blastocystis spp. to humans. A hyperendemic area for STH was found, with hookworm prevalence greater than 50%. Therefore, improvements in WASH as well as mass deworming programs need to be implemented in this area to control and decrease the prevalence of IPs in general and STH in particular.

Blastocystis spp. y su asociación con otros parásitos intestinales en niños de edad preescolar, estado Sucre, Venezuela / Blastocystis spp. and their association to other intestinal parasites in preschool children from Sucre State, Venezuela

Introducción: Blastocystis spp. es uno de los parásitos intestinales más comunes en el ser humano y su patogenicidad sigue siendo controvertida. Objetivo: Determinar la prevalencia de Blastocystis spp. y su asociación con otros parásitos intestinales a niños en edad preescolar. Métodos: Se procesaron 90 muestras fecales provenientes de niños en edad preescolar. Las técnicas copro-parasitológicas usadas fueron: examen directo con solución salina (0,85 por ciento) y lugol. Se usó la prueba chi cuadrado para demostrar la independencia entre las variables: parasitosis, sexo y edad. Se determinó el índice de afinidad de Fager para establecer las asociaciones entre los principales enteroparásitos identificados. Resultados: Se encontraron 68 niños parasitados, con 75,6 por ciento de prevalencia. No hubo diferencias significativas con respecto a la edad y el sexo (p> 0,05). Los parásitos más comunes fueron: Blastocystis spp. (45,6 por ciento), Endolimax nana (30,9 por ciento), Entamoeba coli (26,5 por ciento), y como único helminto, Enterobius vermicularis (1,5 por ciento). El 42,6 por ciento estuvo monoparasitado y 57,4 por ciento biparasitados. Los índices de afinidad (IAB) y pruebas de "t" efectuadas, señalaron asociación significativa entre Blastocystis spp. y los protozoarios E. nana y E. coli. Conclusiones: Se determina una elevada prevalencia de Blastocystis spp. y especies comensales intestinales, todas indicadoras de contaminación fecal, en que probablemente factores ambientales y socioculturales promueven su transmisión. Este tema debe continuarse y profundizarse por la connotación que ha adquirido este parásito en los debates científicos actuales, tanto en el ámbito nacional como internacional(AU)

Introduction: Blastocystis spp. are among the most common intestinal parasites affecting humans. Their pathogenicity continues to be a topic of debate. Objective: Determine the prevalence of Blastocystis spp. and their association to other intestinal parasites in preschool children. Methods: Analysis was performed of 90 stool samples from preschool children. The coproparasitological techniques used were direct examination with 0.85 percent saline solution and lugol. The chi-square test was used to show the independence between the variables parasitic infection, sex and age. Fager's affinity index was determined to establish associations between the main enteroparasites identified. Results: The study found 68 children infected with parasites, for a 75.6 percent prevalence. There were no significant differences with respect to age and sex (p> 0.05). The most common parasites were Blastocystis spp. (45.6 percent), Endolimax nana (30.9 percent) and Entamoeba coli (26.5 percent). The only helminth found was Enterobius vermicularis (1.5 percent). 42.6 percent of the children were infected with one parasite and 57.4 percent with two. The affinity index (IAB) and t tests performed revealed a significant association between Blastocystis spp. and the protozoa E. nana and E. coli. Conclusions: High prevalence was determined of Blastocystis spp. and intestinal protozoan species, all of which were indicative of fecal contamination. Environmental and sociocultural factors are likely to facilitate their transmission. This topic should continue to be addressed and examined due to the relevance of this parasite in current scientific debate, both nationally and internationally(AU)

Blastocystis: estudio coproparasitológico, clínico-epidemiológico y de prevalencia de subtipo 3 en pacientes de hospitales de Bahía Blanca, Argentina / Blastocystis: coproparasitological, clinical-epidemiological and prevalence study of subtype 3 in patients from hospitals in Bahía Blanca, Argentina

Resumen Blastocystis es el parásito unicelular del intestino del hombre y de otros animales más prevalente en seres humanos. Presenta gran variedad genética con múltiples subtipos (ST). Aunque se ha asociado a desórdenes intestinales y extraintestinales, su patogenicidad es discutida. Se analizaron 461 muestras de materia fecal de pacientes sintomáticos (n=380) y asintomáticos (n=81) de hospitales de Bahía Blanca, Argentina; se solicitó consentimiento informado y se completó una ficha epidemiológica. Se realizaron análisis coproparasitológicos, morfometría, recuento y tipificación de Blastocystis ST3 por PCR. La población fue: 57,3% de sexo femenino y 42,7% masculino. La prevalencia de Blastocystis fue de 31% y de Blastocystis ST3 62%. Se hallaron formas vacuolares, granulares y quísticas; las vacuolares fueron las más frecuentes. En el 64,8% de las muestras los Blastocystis fueron pequeños y escasos. El 88,4% de los pacientes sintomáticos presentó trastornos gastrointestinales, el 4% urticaria y el 7,6% fiebre, anemia y bajo peso. El 66,7% de los pacientes con urticaria presentó Blastocystis. La presencia de síntomas se asoció significativamente con Blastocystis (p<0,002). No se hallaron asociaciones estadísticas entre Blastocystis, la edad, el sexo, la disponibilidad de agua potable, de cloacas y el contacto con animales. Dentro de los síntomas sólo se encontró asociación estadística de Blastocystis con urticaria (p<0,007). No hubo asociación entre Blastocystis ST3 y sintomatología. Los resultados destacan la alta prevalencia de Blastocystis y de Blastocystis ST3, la necesidad de hacer un coproparasitológico minucioso, su asociación estadística con urticaria y la importancia de no ignorarlo en el proceso salud-enfermedad.

Abstract Blastocystis is the unicellular parasite of the intestine of man and other animals,most prevalent in humans. It has a great genetic variety with multiple subtypes (ST). Although it has been associated with intestinal and extraintestinal disorders, its pathogenicity remains unclear. Four hundred and sixty one stool samples from symptomatic (n=380) and asymptomatic(n=81) patients from hospitals in Bahía Blanca, Argentina were analysed; informed consent was requested and an epidemiological file was completed. Coproparasitological analysis, morphometry, counting and typing of Blastocystis ST3 were performed by PCR. The population was: 57.3% female and 42.7% male.The prevalence of Blastocystis was 31.0% and that of Blastocystis ST3 62%. Vacuolar, granular and cystic forms were found, with vacuolar forms being the most frequent. Blastocystis were small and scarce in 64.8% of the samples. Most of the symptomatic patients (88.4%) presented gastrointestinal disorders, urticaria 4% and fever, anemia and low weight 7.6%; 66.7% of the urticaria patients presented Blastocystis. The presence of symptoms was significantly associated with Blastocystis (p<0.002). No statistical associations were found between Blastocystis, age, sex, availability of drinking water, sewage, and contact with animals. Within the symptoms, only statistical association of Blastocystis with urticaria was found (p<0.007). There was no association between Blastocystis ST3 and symptomatology. The results highlight the high prevalenceof Blastocystis and Blastocystis ST3, the need for a thorough coproparasitology, their statistical association with urticaria and the importance of not ignoring it in the health-disease process.

Resumo Blastocystis é o parasita unicelular do intestino do homem e outros animais, mais prevalente em seres humanos. Apresenta grande variedade genética com múltiplos subtipos (ST). Embora tenha sido associada a distúrbios intestinais e extraintestinais, sua patogenicidade é debatida. Foram analisadas 461 amostras de fezes de pacientes sintomáticos (n=380) e assintomáticos (n= 81) de hospitais de Bahía Blanca, Argentina; foi solicitado consentimento informado e preenchida uma ficha epidemiológica. Foram realizadas análises coproparasitológicas, morfometria, contagem e tipificação de Blastocystis ST3 por PCR. A população era: 57,3% sexo feminino e 42,7% masculino. A prevalência de Blastocystis foi de 31,0% e de Blastocystis ST3 62%. Foram encontradas formas vacuolares, granulares e císticas, sendo as vacuolares as mais frequentes. Em 64,8% das amostras, os Blastocystis foram pequenos e escassos; 88,4% dos pacientes sintomáticos apresentaram distúrbios gastrointestinais, 4% urticária e 7,6% febre, anemia e baixo peso; 66,7% dos pacientes com urticária apresentaram Blastocystis. A presença de sintomas foi associada significativamente com Blastocystis (p˂0,002). Não foram encontradas associações estatísticas entre Blastocystis, a idade, sexo, a disponibilidade de água potável, de esgoto e o contato com animais. Dentro dos sintomas, só foi encontrada associação estatística de Blastocystis com urticária (p˂0,007). Não houve associação entre Blastocystis ST3 e sintomatologia. Os resultados destacam a alta prevalência de Blastocystis e Blastocystis ST3, a necessidade de fazer um coproparasitologico minucioso, sua associação estatística com urticária e a importância de não ignorá-lo no processo saúde-doença.

An Unusual Case of Extra-Enteric Blastocystosis in the Uterine Cervix.

Extra-enteric infections by Blastocystis spp. have rarely been documented. Here, we report a case of extra-enteric blastocystosis in a patient with minimal cervicitis symptoms. A 47-year-old Hispanic female patient was attended in a primary health centre in Michoacan state, Mexico, for her routine gynaecological medical examination. As only symptom, she referred to a slight vaginal itching. The presence of several vacuolar-stages of Blastocystis spp. were identified by Papanicolaou staining; molecular identification was attempted by culture-PCR sequencing of a region of 18S gene from cervical and faecal samples obtained 2 months after cytological examination, even when patient declared that she tried self-medicating with vaginal ovules. Blastocystis ST1 was identified only in the faecal sample. The presence of Blastocystis spp. in the cervix of a patient with scarce symptomatology, demonstrates the extraordinary flexibility of this microorganism to adapt to new environments and niches.

Infección por Blastocystis spp. en individuos inmunocompetentes e inmunocomprometidos / Blastocystis spp. Infection in immunocompetent and immunocompromised individuals

Blastocystis spp. es un parásito controversial que ha sufrido múltiples reclasificaciones y cuyo rol patógeno para el hombre sigue siendo incierto. Para relacionar la presencia de Blastocystis spp. en pacientes inmunocompetentes e inmunocomprometidos, en ausencia o presencia de sintomatología, se evaluó la morfometría y número de parásitos en individuos procedentes del Servicio Autónomo Hospital Universitario "Antonio Patricio de Alcalá" municipio Sucre, estado Sucre, previo consentimiento informado, durante los meses septiembre a diciembre de 2018. Cada espécimen fecal fue analizado mediante examen directo, la semi-cuantificación del cromista se hizo en diez campos consecutivos de 40X, el análisis morfométrico mediante frotis fecales teñidos con Giemsa observados a 100X y micrometría. Del total de pacientes evaluados (n=162), el cromista ocupó el primer lugar de prevalencia en inmunocompetentes (32,86%), del grupo de inmunocomprometidos los más afectados fueron los desnutridos (8,02%), seguido de los oncológicos y con infección por VIH/SIDA con 5,56% y 1,85% respectivamente. En ambos grupos las manifestaciones clínicas más comunes dolor abdominal, diarrea y flatulencia; con respecto a la cuantificación, se pudo evidenciar que un pequeño grupo de pacientes oncológicos y con desnutrición que presentaban sintomatología, tenían contajes inferiores a 5 parásitos por campo. Al realizar el análisis morfométrico, la forma de cuerpo central fue la única identificada en ambos grupos, coincidiendo con los resultados obtenidos en el examen directo, los morfotipos evaluados presentaron diámetros >10 µm, siendo de mayor diámetro en pacientes inmunocomprometidos que en inmunocompetentes (p<0,05)

Blastocystis spp. it is a controversial parasite that has undergone multiple reclassifications and whose pathogenic role for man remains uncertain. To relate the presence of Blastocystis spp. in immunocompetent and immunocompromised patients, in the absence or presence of symptoms, morphometry and number of parasites in individuals were evaluated, from the of the University Hospital "Antonio Patricio de Alcalá", Cumaná, Sucre state, with prior informed consent, during the months September to December 2018. Each fecal specimen was analyzed by direct examination, the semi-quantification of the chromist was done in ten consecutive fields of 40X, the morphometric analysis by means of fecal smears stained with Giemsa observed at 100X and micrometry. Of the total number of patients evaluated (n = 162), the chromist ranked first in prevalence in immunocompetent (32.86%), of the immunocompromised group the most affected were malnourished patients (8.02%), followed by oncological and with HIV/AIDS infection with 5.56% and 1.85% respectively. In both groups, symptomatic patients were presented, the most common clinical manifestations being abdominal pain, diarrhea and flatulence; with respect to quantification, it was possible to show that a small group of cancer patients with malnutrition who presented symptoms had counts of less than 5 parasites per field. When performing the morphometric analysis, the central body shape was the only one identified in both groups, coinciding with the results obtained in the direct examination, the evaluated morphotypes presented diameters >10 µm, being larger in immunocompromised patients than in immunocompetent patients (p <0.05)

Prevalencia de parásitos intestinales en niños preescolares del municipio Angostura del Orinoco, estado Bolívar, Venezuela. 2016-2018 / Prevalence of intestinal parasites in preschool children from the Angostura del Orinoco municipality, Bolívar state, Venezuela. 2016-2018

El objetivo de la presente investigación fue determinar la prevalencia de parásitos intestinales en niños preescolares usuarios de 12 Centros de Educación Inicial Simoncito (CEIS) del municipio Angostura del Orinoco, estado Bolívar, Venezuela. Se estudiaron las heces de 515 niños de ambos géneros (2 a 5 años), mediante la técnica de sedimentación espontánea. La prevalencia de enteroparásitos fue de 39,4% (n=203). No hubo diferencias estadísticamente significativas (χ2 = 1,59 g.l.: 2 p> 0,05) respecto a la edad, pero si según el género (p<0,05), resultando los niños varones más afectados con 46,9%. Se identificaron 11 taxones de enteroparásitos, destacando el cromista Blastocystis spp. con 27,4% (n=141) y el protozoario Giardia intestinalis con 13,2% (n=68). Se encontró una baja prevalencia de helmintos, donde Ascaris lumbricoides fue el más común con 1,6% (n=8). De los 203 niños parasitados, el 70,9% (n=144) estaba monoparasitado y 29,1% (n=59) poliparasitado. Los principales parásitos asociados fueron Blastocystis spp. (89,8%), G. intestinalis (44,1%) y Endolimax nana (35,3%). En conclusión, se determinó una elevada prevalencia de parásitos intestinales en la población estudiada, por lo que estas infecciones continúan siendo un problema de salud pública en niños de Ciudad Bolívar, Venezuela

The objective of the present investigation was to determine the prevalence of intestinal parasites in preschool children users of 12 Simoncito Initial Education Centers (CEIS) of the Angostura del Orinoco municipality, Bolívar state, Venezuela. The feces of 515 children of both genders (2 to 5 years old) were studied using the spontaneous sedimentation technique. The prevalence of enteroparasites was 39.4% (n = 203). There were no statistically significant differences (χ2 = 1.59 d.f .: 2 p> 0.05) with respect to age but if according to gender (p <0.05), because the most affected were male child with 46.9%. Eleven taxa of enteroparasites were identified, highlighting the chromist Blastocystis spp. (27.4%) and the protozoan Giardia intestinalis (13.2%). A low prevalence of helminths was found, where Ascaris lumbricoides was the most common with 1.6%. Of the 203 parasitized children, 70.9% (n = 144) were monoparasitized and 29.1% (n = 59) polyparasitized. The main associated parasites were Blastocystis spp. (89.8%), G. intestinalis (44.1%) and Endolimax nana (35.3%). In conclusion, a high prevalence of intestinal parasites was determined in the population studied, so these infections continue to be a public health problem in children from Ciudad Bolívar, Venezuela

Molecular genotyping of Blastocystis spp. in wild mammals from Mexico.

Blastocystis spp. are common intestinal parasites found worldwide in humans and a wide range of animals. They exhibit extensive genetic diversity; currently, 17 subtypes (STs) and some groups called non-mammalian and avian STs (NMASTs) have been proposed. In addition, a large variety of animals have been reported as hosts of the parasite, and new hosts and STs are still being described. In this study, Blastocystis infection of wild animals in two sylvatic areas of Mexico was surveyed. Of one hundred twenty-four fecal samples, six were positive for Blastocystis: specifically, one sample from an opossum, one sample from a bat, and four samples from different species of rodents. ST4, ST17, and nucleotide sequences similar to Blastocystis lapemi were identified based on SSU rDNA sequences. To our knowledge, this is the first report to investigate species poorly or not previously evaluated for Blastocystis infection. Mammals having different niches and geographical distribution were infected with similar genetic type of Blastocystis, so that we suggest that local water or food sources could play an important role in Blastocystis transmission and ST maintenance in wild animals. Additionally, there are STs with scarce genetic variation, suggesting that they could be highly adapted to their hosts. These data contribute to our understanding of the host range and genetic diversity of Blastocystis.

Can the pyruvate: ferredoxin oxidoreductase (PFOR) gene be used as an additional marker to discriminate among Blastocystis strains or subtypes?

BACKGROUND: Blastocystis spp. are the most prevalent intestinal eukaryotes identified in humans, with at least 17 genetic subtypes (ST) based on genes coding for the small-subunit ribosomal RNA (18S). It has been argued that the 18S gene should not be the marker of choice to discriminate between STs of these strains because this marker exhibits high intra-genomic polymorphism. By contrast, pyruvate:ferredoxin oxidoreductase (PFOR) is a relevant enzyme involved in the core energy metabolism of many anaerobic microorganisms such as Blastocystis, which, in other protozoa, shows more polymorphisms than the 18S gene and thus may offer finer discrimination when trying to identify Blastocystis ST. Therefore, the objective of the present study was to assess the suitability of the PFOR gene as an additional marker to discriminate among Blastocystis strains or subtypes from symptomatic carrier children. METHODS: Faecal samples from 192 children with gastrointestinal symptoms from the State of Mexico were submitted for coprological study. Twenty-one of these samples were positive only for Blastocystis spp.; these samples were analysed by PCR sequencing of regions of the 18S and PFOR genes. The amplicons were purified and sequenced; afterwards, both markers were assessed for genetic diversity. RESULTS: The 18S analysis showed the following frequencies of Blastocystis subtypes: ST3 = 43%; ST1 = 38%; ST2 = 14%; and ST7 = 5%. Additionally, using subtype-specific primer sets, two samples showed mixed Blastocystis ST1 and ST2 infection. For PFOR, Bayesian inference revealed the presence of three clades (I-III); two of them grouped different ST samples, and one grouped six samples of ST3 (III). Nucleotide diversity (π) and haplotype polymorphism (θ) for the 18S analysis were similar for ST1 and ST2 (π = ~0.025 and θ = ~0.036); remarkably, ST3 showed almost 10-fold lower values. For PFOR, a similar trend was found: clade I and II had π = ~0.05 and θ = ~0.05, whereas for clade III, the values were almost 6-fold lower. CONCLUSIONS: Although the fragment of the PFOR gene analysed in the present study did not allow discrimination between Blastocystis STs, this marker grouped the samples in three clades with strengthened support, suggesting that PFOR may be under different selective pressures and evolutionary histories than the 18S gene. Interestingly, the ST3 sequences showed lower variability with probable purifying selection in both markers, meaning that evolutionary forces drive differential processes among Blastocystis STs.

Is the genetic variability of Cathepsin B important in the pathogenesis of Blastocystis spp.?

The potential role of Blastocystis as a pathogen is controversial because it is found in both symptomatic and asymptomatic carriers. Since Cathepsin B has been identified as a main virulence factor that contributes to the pathogenesis of this parasite, the purpose of this study was to analyze the genetic polymorphisms of cathepsin B from Blastocystis from patients with irritable bowel syndrome and from asymptomatic carriers. DNA from fecal samples of both groups, which were previously genotyped by 18S sequencing, was used to amplify a fragment of the cathepsin B gene. Phylogenetic reconstructions were performed and some genetic population indexes were obtained. Amplicons of 27 samples (15 cases, 10 controls, and two commercial ATCC strains) were obtained and analyzed. Phylogenetic reconstructions using nucleotides or inferred amino acid sequences did not separate between cases or controls or among subtypes. Regarding the values of genetic variability, we found that the haplotype and nucleotide diversity indexes of cathepsin B from cases and controls were similar to the values of 18S from controls. By contrast, 18S from cases showed low variability, suggesting that the genetic variability of cathepsin B was not related to the symptomatology of Blastocystis carriers. However, since no polymorphisms related to cases or controls were found, it is logical to assume that the potential damage caused by Blastocystis in situ may be due to unclear mechanisms of Cathepsin B regulation and expression that should be studied in future studies.

Occurrence of Blastocystis spp. in domestic animals in Triângulo Mineiro area of Brazil

Abstract INTRODUCTION: Currently, there are few studies regarding Blastocystis epidemiology. This study aimed to evaluate the occurrence of Blastocystis in animals in Uberaba, Brazil. METHODS: Fecal samples were examined by parasitological methods and screened for Blastocystis by polymerase chain reaction. RESULTS: Blastocystis spp. were observed in pigs, sheep, cattle, and dogs. Blastocystis polymerase chain reaction was positive in 14/22 samples positive by parasitological methods. CONCLUSIONS: The occurrence of Blastocystis in animals is high, with a predominance of subtype 1 in the region. This is the first study conducted in Brazil showing the genetic profile of Blastocystis isolated from animals.

Blastocystis spp.: avances, controversias y desafíos futuros / Blastocystis spp.: Advances, controversies and future challenges

Blastocystis spp. es el protista intracelular que se detecta con mayor frecuencia en muestras de materia fecal humana; las tasas de infección pueden superar el 20% en países en vías de desarrollo. El hallazgo de este parásito en heces de diversas especies animales sugiere su potencial zoonótico. La relevancia clínica y el papel patógeno de Blastocystis spp. en el tracto intestinal son inciertos. Varias son las publicaciones que lo reconocen como agente etiológico de desórdenes intestinales como diarrea, enfermedad inflamatoria intestinal y colitis ulcerosa, aunque la patogenicidad de este parásito no ha sido probada. Este amplio rango de respuestas a la infección podría estar relacionado con la diversidad genética de los aislamientos provenientes de hospedadores infectados.

Blastocystis spp. is the most common protozoan detected in human stool samples. In developing countries, infection rates are higher than 20%. The presence of this parasite in the feces of several host species suggests its zoonotic potential. The clinical relevance and the pathogenic role of Blastocystis spp. in the intestinal tract remain unclear. There are several clinical reports that recognize it as the etiologic agent of several intestinal disorders such as diarrhea, inflammatory bowel disease and ulcerative colitis, although the pathogenicity of this parasite has not been proved yet. This wide range of clinical manifestations could be related to the genetic diversity exhibited by this parasite.

[Blastocystis spp.: Advances, controversies and future challenges]. / Blastocystis spp.: avances, controversias y desafíos futuros.

Blastocystis spp. is the most common protozoan detected in human stool samples. In developing countries, infection rates are higher than 20%. The presence of this parasite in the feces of several host species suggests its zoonotic potential. The clinical relevance and the pathogenic role of Blastocystis spp. in the intestinal tract remain unclear. There are several clinical reports that recognize it as the etiologic agent of several intestinal disorders such as diarrhea, inflammatory bowel disease and ulcerative colitis, although the pathogenicity of this parasite has not been proved yet. This wide range of clinical manifestations could be related to the genetic diversity exhibited by this parasite.

Prevalencia de enteroparasitos en individuos seropositivos y seronegativos a los virus HTLV-I/II

Para determinar la prevalencia de enteroparásitos en individuos seropositivos a los virus HTLV-I/II, se seleccionaron aleatoriamente 75 donantes que asistieron a los Bancos de Sangre de dos instituciones sanitarias del municipio Maracaibo, Venezuela. Se contactaron personalmente 50 individuos seropositivos a virus HTLV-I/II (grupo muestra) y 25 seronegativos (grupo control), quienes aportaron una muestra fecal para diagnóstico parasitológico. Estas fueron sometidas al examen al fresco con solución salina fisiológica (SSF) al 0,85%, tinción temporal de Lugol y técnica de concentración con formol-éter (Ritchie). Además se realizó cultivo en Agar Nutritivo (método de Arakaki) para investigar la presencia de larvas de Strongyloides stercoralis. Se determinó una prevalencia general de enteroparásitos en el grupo muestra de 54% y 44% en el grupo control. Predominó el monoparasitismo entre todos los individuos estudiados. Las especies identificadas fueron: Blastocystis spp. 47,3% y 15,4%, Entamoeba coli 21% y 15,4%, Endolimax nana 13% y 53,8%, Complejo Entamoeba 10,5% y 15,4%, Giardia intestinalis 5,2% y 0%, y Entamoeba hartmanni 2,6% y 0% en el grupo muestra y grupo control, respectivamente. No se detectó Strongyloides stercoralis ni otros helmintos intestinales, en los individuos estudiados. Blastocystis spp. fue el más frecuente en los pacientes seropositivos (diferencia estadísticamente significativa) que en el grupo control, lo que pudiese relacionarse con una mayor persistencia de este cromista en pacientes coinfectados con HTLV-I/II. Se puede concluir que el estatus serológico del individuo HTLV-I/II positivo parece no influir en la presencia o adquisición de parásitos intestinales.

Prevalence of intestinal parasites in seropositive and seronegative to HTLV I/II viruses

The prevalence of intestinal parasites in individuals seropositive for the HTLV-I/II virus was studied. A total of 75 donors who attended the blood banks of two health institutions in Maracaibo, Venezuela were randomly selected: 50 patients seropositive for HTLV-I/II (study group) and 25 seronegative individuals (control group). The participants in the study were all contacted personally, after which they provided a fecal sample for parasitological diagnosis. The fresh samples were examined using 0.85% physiological saline solution (PSS), Lugol’s solution for temporary staining and the formalin-ether concentration technique (Ritchie). In addition, samples were cultured on nutrient agar (Arakaki method) to determine the presence of Strongyloides stercoralis larvae. Overall prevalences of 54% intestinal parasites in the study group and 44% in the control group were found. Monoparasitism prevailed among all the individuals studied. The species identified in the study and control groups were: Blastocystis spp. 47.3% and 15.4%, Entamoeba coli 21% and 15.4%, Endolimax nana 13.0% and 53.8%, Entamoeba complex 10.5% and 15.4%, Giardia intestinalis 5.2% and 0%, and Entamoeba hartmanni 2.6% and 0 %, respectively. Strongyloides stercoralis and other intestinal helminths were not detected in the individuals studied. Blastocystis spp. was significantly more common in seropositive patients than in the control group, which could be associated with a greater persistence of this chromista in patients co-infected with HTLV-I / II.It can be concluded that the positive serological status of HTLV-I / II infected individuals does not seem to influence either the presence or acquisition of intestinal parasites.

Prevalencia de parásitos intestinales en escolares de Ciudad Bolívar, Venezuela: comparación entre dos períodos / Prevalence of intestinal parasites in school children from Ciudad Bolívar, Venezuela: comparison between two periods

Se determinó la prevalencia de parásitos intestinales en 921 escolares de 9 escuelas de Ciudad Bolívar, estado Bolívar, Venezuela durante el período 2009-2013 y se comparó con la obtenida en la misma ciudad en el período 1995-1996, en 7 escuelas y 446 niños. En la primera oportunidad las muestras fecales fueron analizadas mediante examen directo y técnica de Willis; mientras que para la segunda, las heces fueron sometidas al directo, Kato y sedimentación espontánea. La prevalencia general de enteroparásitos para los períodos 1995-1996 y 2009-2013 fue de 52% y 62,9% respectivamente. En el primer período prevalecieron los helmintos y para el segundo el grupo de Chromistas-Protozoarios resulto más prevalente. Para 1995-1996, los helmintos Trichuris trichiura (24,2%) y Ascaris lumbricoides (19,5%) resultaron más comunes; mientras que para el período 2009- 2013, el chromista Blastocystis fue el más prevalente (47,6%), seguido del protozoario Endolimax nana (17,7%). En todos esos casos la diferencia fue significativa (p<0,05) cuando se comparan las prevalencias de ambos períodos. Se concluye que hubo un cambio en la prevalencia de los parásitos intestinales en la población evaluada: en el primer período (1995-1996) predominaron los helmintos y para el segundo (2009-2013) el chromista Blastocystis spp. y los protozoarios.

The prevalence of intestinal parasites in 921 schoolchildren from nine schools in Ciudad Bolivar, Bolivar State, Venezuela during the period 2009-2013 was determined and compared with that obtained in the same city in the period 1995-1996 in seven schools and 446 children. At the first opportunity the fecal samples were analyzed by direct examination and Willis technical; while for the second, feces were submitted to direct, Kato and spontaneous sedimentation. The overall prevalence of intestinal parasites for the periods 1995-1996 and 2009-2013 was 52% and 62.9% respectively. In the first period, the helminths prevailed and the second, the Chromistas-Protozoa group turned more prevalent. For 1995-1996, the helminths Trichuris trichiura (24.2%) and Ascaris lumbricoides (19.5%) were more common; while for the period 2009-2013, the Chromista Blastocystis spp. was the most prevalent (47.6%), followed by protozoan Endolimax nana (17.7%). In all these cases the difference was significant (p <0.05) when the prevalence of both periods being compared. We conclude that there was a change in the prevalence of intestinal parasites in the study population: in the first period (1995-1996) dominated the helminths and the second (2009-2013) the Chromista Blastocystis spp. and protozoa.

Morbilidad por Blastocystis spp. en el Hospital Pediátrico Universitario William Soler / Morbidity from Blastocystis spp. at William Soler university pediatric hospital

Introducción: Blastocystis spp. se considera actualmente un posible nuevo patógeno intestinal, y se reconoce su existencia en edad pediátrica.Objetivo: identificar el patrón clínico y epidemiológico de infección por Blastocystis spp.Métodos: estudio descriptivo en 98 pacientes cuyas heces fueron recepcionadas en el Departamento de Parasitología del Hospital Pediátrico William Soler (2008 a 2009), en La Habana.Resultados: Blastocystis spp. se manifestó de forma única en 59,2 por ciento, significativamente superior (p= 0,000) respecto a su presentación en coinfección (26,7 por ciento), principalmente con Giardia lambia (17,3 por ciento) y Entamoeba histolytica/E. dispar (11,2 por ciento). En infección solo por Blastocystis spp. (n= 58), la tasa de infección se incrementó de 47,2 por ciento (1 y 4 años), a 83,3 por ciento (13 a 18 años), y en el sexo masculino hubo mayor riesgo de contraer el parásito (razón o cociente de tasas= 0,7). La razón de tasa de Blastocystis spp., según zona de residencia y abasto de agua, fue menor que 1; mientras que, para la tenencia de animales en la casa y el origen del agua para consumo, fue superior a 1. La sintomatología se expresó en 96,6 por ciento, básicamente por dolor abdominal y diarrea.Conclusiones: la infección por Blastocystis spp. de forma única es típica en este estudio de 13 a 18 años, con riesgo incrementado en el sexo masculino, por la tenencia de animales en la casa, consumo de agua sin hervir, zona de residencia urbana y consumo de agua de acueducto. Los principales síntomas corresponden a dolor abdominal y diarrea(AU)

Morbilidad por blastocystis spp. en el hospital pediátrico universitario "William Soler" / Morbidity from blastocystis spp. at "William Soler" university pediatric hospital

INTRODUCCIÓN: blastocystis spp. se considera actualmente un posible nuevo patógeno intestinal, y se reconoce su existencia en edad pediátrica. OBJETIVO: identificar el patrón clínico y epidemiológico de infección por Blastocystis spp. MÉTODOS: estudio descriptivo en 98 pacientes cuyas heces fueron recepcionadas en el Departamento de Parasitología del Hospital Pediátrico "William Soler" (2008 a 2009), en La Habana. RESULTADOS: Blastocystis spp. se manifestó de forma única en 59,2 %, significativamente superior (p= 0,000) respecto a su presentación en coinfección (26,7 %), principalmente con Giardia lambia (17,3 %) y Entamoeba histolytica/E. dispar (11,2 %). En infección solo por Blastocystis spp. (n= 58), la tasa de infección se incrementó de 47,2 % (1 y 4 años), a 83,3 % (13 a 18 años), y en el sexo masculino hubo mayor riesgo de contraer el parásito (razón o cociente de tasas= 0,7). La razón de tasa de Blastocystis spp., según zona de residencia y abasto de agua, fue menor que 1; mientras que, para la tenencia de animales en la casa y el origen del agua para consumo, fue superior a 1. La sintomatología se expresó en 96,6 %, básicamente por dolor abdominal y diarrea. CONCLUSIONES: la infección por Blastocystis spp. de forma única es típica en este estudio de 13 a 18 años, con riesgo incrementado en el sexo masculino, por la tenencia de animales en la casa, consumo de agua sin hervir, zona de residencia urbana y consumo de agua de acueducto. Los principales síntomas corresponden a dolor abdominal y diarrea.

INTRODUCTION: blastocystis spp. is presently considered a possible new intestinal pathogen and its presence is recognized at pediatric ages. OBJECTIVE: to identify the clinical and epidemiological pattern of infection caused by Blastocystis spp. METHODS: descriptive study of 98 patients whose feces were collected at the department of parasitology in "William Soler" pediatric hospital (2008-2009) in Havana. RESULTS: Blastocystis spp. manifested in 59.2 % of cases, significantly higher (p= 0.000) rate than in co-infection (26.7 %) mainly with Giardia lambdia (17.3 %) and Entamoeba histolytica/E. dispar (11.2 %). Regarding infection just by Blastocystis spp. (n= 58), the infection rate rose from 47.2 % (1 and 4 years-old) to 83.3 % (13 to 18 years-old) and males had higher risks of acquiring the parasites (ratio rate= 0.7). The rate ratio of Blastocystisspp., according to the area of residence and water supply system, was lower than 1 whereas having pets at home and origin of the drinking water was over 1. Abdominal pain and diarrheas were the basic symptoms found in 96.6 % of the sample. CONCLUSIONS: single Blastocystis spp. infection is typical in this study in the 13-18 years old group, with increased risk for males, pets at home, taking water that is not boiled, urban area of residence and consumption of tap water. The main symptoms were abdominal pain and diarrheas.