Irritable Bowel Syndrome Associated with Blastocystis hominis or Without Relationship to It? A Case-Control Study and Minireview.

BACKGROUND: Blastocystis hominis (B. hominis) is a protozoan parasite that has a worldwide distribution. Some studies have suggested a link between B. hominis and the development of irritable bowel syndrome (IBS). The objective of this study was to determine the prevalence of B. hominis in patients with IBS compared to healthy individuals. MATERIAL AND METHODS: A total of 65 stool samples from patients with IBS and 65 samples from healthy individuals in northern Iran were examined. The samples were tested using various methods including direct smear, formalin ether sedimentation and culture to detect the presence of B. hominis. Additionally, polymerase chain reaction (PCR) was performed on all culture-positive isolates to confirm the results and identify the genotype. RESULTS: B. hominis was detected in 15.38% of IBS patients and 9.2% of the healthy group. The culture in RPMI1640 was found to be better than the formalin ether and direct smear methods. Positive samples were confirmed using the molecular method. No significant difference was observed in the order of B. hominis infection between the two groups. CONCLUSIONS: The results of our study indicate that no significant difference was observed in the order of B. hominis infection between IBS patients and healthy groups. Therefore, further study is necessary to determine the potential pathogenic effects of this parasite and its role in causing IBS.

Unexpected Presence of Blastocystis Subtype 1-3 DNA in Human Vaginal and Sperm Samples Coinfected with Trichomonas vaginalis.

There have been few reports on extra-enteric infections by Blastocystis STs and none have been molecularly identified in samples from human reproductive organs. We report for the first time the identification of 3 different subtypes of Blastocystis (ST1-3) in vaginal and sperm samples, from patients infected with Trichomonas vaginalis. Blastocystis STs were identified by PCR-sequencing and by phylogenetic inferences using 28 vaginal swab samples and 7 sperm samples from patients trichomoniasis. Blastocystis STs were identified in 6 of 28 vaginal swabs (21.4%) and in 3 of 7 sperm samples (42.8%). In both biological samples, STs 1-3 were found; one vaginal sample showed subtype co-infection with ST1 and ST3. High genetic variation was observed in the sequences obtained and no specific clustering in the phylogenetic trees was detected. Most of the haplotypes identified were placed far from the main dispersal centers. Our finding suggested that incorrect cleaning of the genital area or a contamination by combination of anal and vaginal intercourse.

Influence of Blastocystis hominis on the small intestine and lactase enzyme activity.

Blastocystis hominis is a cosmopolitan protozoan that has been associated with several gastrointestinal disturbances involving lactose intolerance. However, the underlying pathogenic factors remain indistinct. 20 Swiss albino mice were utilized and assembled into four groups, each of five mice: group-I: received neither infection nor lactose (healthy control), group-II: received a single dose of 10,000 cysts of Blastocystis and lactose diets in a dose of 12.5 g/day/mouse for 7 consecutive days starting from day 14 p.i., group-III: non-infected mice with oral doses of lactose (12.5 g/day/mouse) for 7 consecutive days (positive control), group-IV: infected mice on lactose free diet (negative control). We investigated the histopathological changes using H&E stain.s Also, lactase enzyme activity was measured using spectrophotometry and the production of TNF-α and apoptotic events were explored via immunohistochemistry and compared in the small intestine of all groups. The active inflammatory changes in the infected animals were moderate in the form of loss of villous architecture, increased ILC (P-value > 0.001) besides scattered forms of the parasite as compared to non-infected mice. There was a reduction in lactase enzyme activity p.i. The TNF-α levels were induced p.i. as compared to non-infected mice (P-value > 0.001). The expression of Bax protein was upgraded, while Bcl-2 expression decreased significantly with a reverse in Bax/Bcl2 ratio in infected animals. Blastocystis infection appears to humble lactase enzyme activity via the induction of apoptosis in the epithelial cells of the small intestinal brush border in a TNF-α associative pathway.

Worldwide prevalence of emerging parasite Blastocystis in immunocompromised patients: A systematic review and meta-analysis.

BACKGROUND: Blastocystis is one of the most common pathogens of the human intestine, caused by an emerging parasite, which can lead to severe symptoms and even death in immunocompromised patients. We aimed to determine the global prevalence of Blastocystosis infection in people with immunodeficiency. A systematic literature search was conducted on Web of Science, Scopus, Google scholar, Science Direct and MEDLINE databases to select all observational studies reporting the prevalence of Blastocystosis infection in Worldwide, based on different diagnostic methods in immunocompromised patients of any age and published from inception to February 2019. Pooled estimates and 95% confidence intervals (95% CIs) were calculated using random effects models and in addition, the I2 statistic was calculated. The geographic distribution of studies was evaluated and the diagnosis of Blastocystis was compared by various techniques. Electronic databases were reviewed for Blastocystosis infection in HIV/AIDS, cancer and other immunocompromised patients, and meta-analyses were conducted to calculate the overall estimated prevalence. Total68 eligible studies were included. The estimated pooled prevalence rate of Blastocystosis infection in immunocompromised patients was overall 10% (95% CI, 7-13%; I2 96.04%) (P < 0.001), of whom 21% [18-25] were in Australia, 12% [4-24] in America, 11% [6-17] in Europe and 10% [5-15], 7% [3-13] in Asia and Africa, respectively. It was calculated that the estimated pooled prevalence rate of Blastocystosis infection in immunocompromised patients was overall 10% and the prevalence estimates ranged from 0.44 to 72.39. Also, overall the prevalence of parasites co-infection in immunocompromised patients was detected as 0.024%. Our finding showed that immunocompromised people show a high prevalence of Blastocystosis infection compared to the control population. Adequate information on the prevalence rate is still missing from many countries. However, current information underscore that Blastocystis should not be neglected.

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.

Comparing spatio-temporal distribution of the most common human parasitic infections in Iran over two periods 2007 to 2012 and 2013 to 2018: A systematic quantitative literature review.

This study analyses the spatio-temporal trend of the prevalence of the four most prevalent parasitic diseases in Iran over two periods, 2007 to 2012 and 2013 to 2018, indicating high-risk and low-risk areas. Out of 19 126 articles, we selected 220 articles for data extraction and calculated the pooled prevalence for cutaneous leishmaniasis, human toxoplasmosis, giardiasis and blastocystosis for all 31 provinces in the country. Anselin local Moran's I was used to identify clusters and outliers in the prevalence rates. The mean prevalence of cutaneous leishmaniasis patients was found 35.12 per 100 000 in 2007 to 2012 but fell to 19.12 per 100 000 in the 2013 to 2018 period. The mean prevalence of acute and chronic toxoplasmosis was 2.36% and 32.5%, respectively, in 2007 to 2012, which changed to 2.28% and 31.14% in 2013 to 2018. The total prevalence of giardiasis declined from 9.8% in 2007 to 2012 to 4.8% in 2013 to 2018, while the mean prevalence of blastocystosis declined from 8.9% in 2007 to 2012 to 6.76% in the 2013 to 2018 period. There was only one high-high cluster in 2007 to 2012 and that was due to giardiasis, while there were two in 2013 to 2018, one for blastocystosis and one for chronic toxoplasmosis. The total prevalence of blastocystosis, giardiasis and cutaneous leishmaniasis in Iran has continually declined since 2007. In contrast, the prevalence of toxoplasmosis in pregnant Iranian women has not been changed. Iran's Midwest has more parasitic infections compared to the Mideast, which may be explained by the existence of vast deserts and consequently dry and hot climate in the latter part of the country.

Asociación entre blastocistosis y anemia por déficit de hierro en mujeres embarazadas en el municipio La Lisa, La Habana, Cuba / Association between Blastocystosis and Iron Deficiency Anemia in Pregnant Women in La Lisa Municipality, Havana, Cuba

Introducción: Estudios recientes encontraron asociación entre blastocistosis y anemia por déficit de hierro. Uno de ellos demostró que en mujeres embarazadas la infección por Blastocystis spp. es un factor de riesgo para padecerla y puede tener consecuencias adversas tanto para la madre, como para el feto que en casos extremos puede conducir a mortalidad maternofetal. Objetivo: Conocer la prevalencia de blastocistosis en mujeres embarazadas y su posible asociación con la anemia ferropénica. Métodos: Se realizó un estudio parasitológico, clínico y epidemiológico, de tipo descriptivo y de corte transversal, al universo de las gestantes atendidas en tres policlínicos del municipio La Lisa, entre julio 2017 y junio 2018. Resultados: De 135 embarazadas, 43 (31,9 por ciento) estaban infectadas por protozoos parásitos. De estos, Blastocystis spp, fue el más prevalente (28,9 por ciento). Del total de gestantes, 41 padecían de anemia. En la mayoría de estas (85,4 por ciento), la anemia clasificaba como ferropénica. La proporción de embarazadas parasitadas por Blastocystis spp. que padecían este tipo de anemia, en relación con las gestantes que no estaban infectadas por ese protozoo y también padecían de ese tipo de anemia fue significativamente mayor (p lt; 0,05). Conclusiones: Blastocistosis es una parasitosis de prevalencia creciente e insuficientemente conocida. Iniciativas para mejorar conocimientos, percepciones y prácticas en relación con su diagnóstico, tratamiento y control son perentorias a nivel popular y académico. Las estrategias de comunicación que se implementen deben informar sobre las posibles consecuencias clínicas de la infección en relación con la mujer embarazada(AU)

Introduction: Recent studies found an association between blastocystosis and iron deficiency anemia. One of them showed that the infection with Blastocystis spp is a risk factor for in pregnant women to suffer. This infection can have adverse consequences for both the mother and the fetus. In extreme cases it can lead to maternal and fetal mortality. Objective: To know the prevalence of blastocystosis in pregnant women and its possible association with iron deficiency anemia. Methods: A parasitological, clinical and epidemiological study, descriptive and cross-sectional was conducted on the universe of pregnant women treated in three clinics in La Lisa municipality from July 2017 to June 2018. Results: We found 43 (31.9 percent) pregnant women infected by parasitic protozoa out of 135 who were studied. Blastocystis spp, was the most prevalent (28.9 percent). 41 pregnant women suffered from anemia. In most of them (85.4 percent), anemia classified as iron deficiency. The proportion of pregnant women parasitized by Blastocystis spp who suffered from this type of anemia was significantly higher (p lt;0.05) in relation to pregnant women who were not infected by that protozoan and also suffered from that type of anemia. Conclusions: Blastocystosis is a parasitosis of increasing prevalence which is insufficiently known. Initiatives to improve knowledge, perceptions and practices are peremptory to their diagnosis, treatment and control at the general and academic levels. The communication strategies that are implemented should inform about possible clinical consequences of this infection in pregnant woman(AU)

Blastocystis hominis transmission by non-potable water: a case report in Italy.

In the reported case, a 41-year-old Italian man came to the clinician's observation reporting cramps, bloating and watery diarrhoea a few days after drinking water indicated as unpotable from a fountain in a farm area. The medical suspicion was directed at both gluten intolerance and enteric infection, eventually of waterborne origin. Gluten intolerance was investigated by intestinal biopsy and excluded, while stool analyses ruled out infective bacteriological or viral agents and parasites. Subsequently, a persistent eosinophilia was revealed and a parasitological analysis was again suggested, planning for a more sensitive molecular method. Therefore, a multiplex-PCR of enteric protozoa species DNA was performed on an intestinal biopsy and faecal samples revealing only Blastocystis hominis protozoa, subsequently typed as subtype 1 by RFLP-PCR method. B. hominis is an anaerobic protozoa found in the human and animal intestinal tract, recently associated with a pathogenic role characterized by chronic development. Since blastocystosis has been demonstrated as a waterborne infection, a sample of water matrix was analysed, revealing the B. hominis subtype 1 DNA inside. A probable water transmission of Blastocystis infection has been demonstrated in this case report. Only a probiotic treatment based on Saccharomyces boulardii was administered to the patient and this apparently resolved the infection. In summary, the case described here is a chronic blastocystosis of possible waterborne origin, controlled by assuming a yeast treatment.

Blastocystis sp. en humanos: actualización y experiencia clínico-terapéutica

Blastocystis sp. es uno de los parásitos del humano más frecuentemente identificados en el laboratorio clínico durante el estudio parasitológico de las muestras de heces. En esta revisión se actualizan los aspectos relativos a la diversidad genética y especificidad del huésped, la taxonomía, caracterización molecular, formas clínicas y experiencia terapéutica en pacientes inmuno-competentes y comprometidos, sintomáticos y asintomáticos, de la consulta de la Sección de Geohelmintiasis del Instituto de Medicina Tropical de la Facultad de Medicina de la Universidad Central de Venezuela, proponiendo el secnidazol como droga de primera elección. Se analiza la presencia de Blastocystis como patógeno humano o como comensal, formando parte de la microbiota intestinal. Se considera la tendencia actual entre los diferentes grupos de investigación a mirar la blastocistosis como un problema de salud pública en lugar de una entidad clínica frecuente y se incluyen elementos que pudieran reforzar esta visión. Se incluyen las medidas que pudieran contribuir a prevenir la parasitosis. Dado que la investigación sobre este parásito progresa rápidamente, se recomienda realizar revisiones frecuentes para mantener actualizados los conceptos relacionados con su epidemiología, diagnóstico, tratamiento y prevención en el paciente inmunocompetente así como en el inmunosuprimido.

Blastocystis sp. is one of the human parasites most frequently identified in the clinical laboratory during the parasitological study of stool samples. This review updates the aspects related to genetic diversity and host specificity, taxonomy, molecular characterization, clinical forms and therapeutic experience in symptom free and symptomatic immune-competent and compromised patients who attended to the Soil Transmitted Helminth Section of the Institute of Tropical Medicine of the Faculty of Medicine of the Central University of Venezuela, proposing secnidazole as the drug of first choice. The presence of Blastocystis as human pathogen or as part of the gut microbiota, are analyzed. The current trend among the different research groups is to look at Blastocystosis as a public health problem rather than a common clinical entity and include elements that could reinforce this view. Measures that could help prevent parasitic disease are also included. Since research on this parasite is progressing rapidly, frequent reviews are recommended to keep the concepts related to its epidemiology, diagnosis, treatment and prevention updated in the immunocompetent as well as the immunosuppressed patient.

Modulating the Gut Micro-Environment in the Treatment of Intestinal Parasites.

The interactions of micro-organisms cohabitating with Homo sapiens spans millennia, with microbial communities living in a symbiotic relationship with the host. Interacting to regulate and maintain physiological functions and immunological tolerance, the microbial community is able to exert an influence on host health. An example of micro-organisms contributing to an intestinal disease state is exhibited by a biodiverse range of protozoan and bacterial species that damage the intestinal epithelia and are therefore implicated in the symptoms of diarrhea. As a contentious exemplar, Blastocystis hominis is a ubiquitous enteric protist that can adversely affect the intestines. The symptoms experienced are a consequence of the responses of the innate immune system triggered by the disruption of the intestinal barrier. The infiltration of the intestinal epithelial barrier involves a host of immune receptors, including toll like receptors and IgM/IgG/IgA antibodies as well as CD8+ T cells, macrophages, and neutrophils. Whilst the mechanisms of interactions between the intestinal microbiome and protozoan parasites remain incompletely understood, it is acknowledged that the intestinal microbiota is a key factor in the pathophysiology of parasitic infections. Modulating the intestinal environment through the administration of probiotics has been postulated as a possible therapeutic agent to control the proliferation of intestinal microbes through their capacity to induce competition for occupation of a common biotype. The ultimate goal of this mechanism is to prevent infections of the like of giardiasis and eliminate its symptoms. The differing types of probiotics (i.e., bacteria and yeast) modulate immunity by stimulating the host immune system. Early animal studies support the potential benefits of probiotic administration to prevent intestinal infections, with human clinical studies showing probiotics can reduce the number of parasites and the severity of symptoms. The early clinical indications endorse probiotics as adjuncts in the pharmaceutical treatment of protozoan infections. Currently, the bar is set low for the conduct of well-designed clinical studies that will translate the use of probiotics to ameliorate protozoan infections, therefore the requisite is for further clinical research.

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.

Evidencias y mecanismos de patogenicidad de Blastocystis sp / Evidence and pathogenicity mechanisms of Blastocystis sp

INTRODUCCIÓN: durante las últimas dos décadas se acumularon evidencias que favorecen la aceptación del carácter patógeno de Blastocystis sp. Sin embargo, esos argumentos no son aún del conocimiento de la inmensa mayoría de los profesionales relacionados con el diagnóstico, tratamiento y control de las parasitosis intestinales, en general, y de la blastocistosis, en particular. OBJETIVOS: revisar lo publicado sobre las evidencias en favor de la patogenicidad de Blastocystis sp. y hasta dónde la información acumulada permite exponer los mecanismos por los cuales este parásito puede causar daños en el hospedero humano. MÉTODOS: con el auxilio de diferentes buscadores electrónicos, se realiza una revisión de los artículos sobre patogenicidad de Blastocystis sp. publicados durante el período 1994-2014. Puntualmente, algunas monografías y artículos originales fechados con anterioridad al intervalo mencionado también fueron consultados. CONCLUSIONES: evidencias clínicas, fenotípicas y genotípicas acumuladas durante los últimos tres lustros favorecen la aceptación del carácter patógeno de Blastocystis sp. y estas, una vez difundidas ente los profesionales correspondientes, deberán ser tenidas en cuenta para la realización de un mejor diagnóstico, tratamiento y control de esta parasitosis.

INTRODUCTION: Evidence has been gathered in the past two decades which leads to recognizing the pathogenic nature of Blastocystis sp. However, these arguments are still not known to the vast majority of professionals engaged in the diagnosis, treatment and control of intestinal parasitosis in general and blastocystosis in particular. OBJECTIVES: Review publications containing evidence of the pathogenicity of Blastocystis sp. and determine whether the information accumulated allows description of the mechanisms by which this parasite may cause damage to human hosts. METHODS: Various search engines were used to find and review papers published in the period 1994-2014 dealing with the pathogenicity of Blastocystis sp. Several monographs and original papers dated before the above mentioned period were also consulted. CONCLUSIONS: Clinical, phenotypic and genotypic evidence accumulated in the last fifteen years lead to recognizing the pathogenic nature of Blastocystis sp. Once made known to the corresponding professionals, such evidence should be borne in mind to improve the quality of the diagnosis, treatment and control of this parasitosis.

Patogenicidad de Blastocystis sp. Evidencias y mecanismos / Pathogenicity of Blastocystis sp. Evidence and mechanisms

Introducción: durante las últimas dos décadas se acumularon evidencias que favorecen la aceptación del carácter patógeno de Blastocystis sp. Sin embargo, esos argumentos no son aún del conocimiento de la inmensa mayoría de los profesionales relacionados con el diagnóstico, tratamiento y control de las parasitosis intestinales, en general, y de la blastocistosis, en particular. Objetivos: revisar lo publicado sobre las evidencias en favor de la patogenicidad de Blastocystis sp. y, hasta dónde la información acumulada permite, exponer los mecanismos por los cuales este parásito puede causar daños en el hospedero humano. Métodos: con el auxilio de diferentes buscadores electrónicos, se realiza una revisión de los artículos sobre patogenicidad de Blastocystis sp. publicados durante el período 1994-2014. Puntualmente, también fueron consultados, algunas 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 clínicas, fenotípicas y genotípicas acumuladas durante los últimos tres lustros favorecen la aceptación del carácter patógeno de Blastocystis sp. y éstas, una vez difundidas ente los profesionales correspondientes, deberán ser tenidas en cuenta para la realización de un mejor diagnóstico, tratamiento y control de esta parasitosis(AU)

Introduction: during the last two decades, evidence supporting the pathogenic character of Blastocystis sp. accumulated. Nevertheless, those arguments are still unknown by the great majority of professionals related with diagnosis, treatment and control of the intestinal infectious in general, and of the blastocystosis in particular. Objectives: to review published materials about pieces of evidence that support the acceptance of the pathogenicity of Blastocystis sp., and to what extent the information accumulated allows revealing the mechanisms by which this parasite causes damage to the human host. Methods: through different search engines, papers about pathogenicity of Blastocystis sp. published during 1994-2014 period were reviewed. Additionally, some monograph and papers dated previously to the mentioned interval were also consulted. Results: updated information about the selected topics, with academic and practical approach, were presented and analyzed. Conclusions: clinical, phenotypic and genetic pieces of evidence accumulated during the last fifteen years support the pathogenic character of Blastocystis sp. Once they are adequately integrated into the practice of the corresponding professionals the diagnosis, treatment and control of blastocystosis could be improved(AU)

Investigación de blastocystis sp. en agua de consumo humano en una población escolar de la zona rural del estado Mérida, Venezuela / Blastocystis sp. in drinking water at a rural school in Mérida, Venezuela

Para detectar la presencia de Blastocystis sp. en el agua de consumo de una escuela rural del estado Mérida, se recolectaron 36 muestras provenientes de la fuente natural que surte el tanque de distribución, del tanque y de los grifos, durante los meses de Septiembre 2008, Febrero y Diciembre del 2009 y Mayo 2010. El procesamiento de las muestras se realizó siguiendo la técnica propuesta por Suresh y col. (2005). Los resultados sugieren que el agua de consumo estaba exenta de Blastocystis o que la cantidad de quistes viables presentes en las muestras fue muy baja, lo que no permitió lograr la recuperación del parásito en el cultivo. Por ello se requiere el uso de técnicas más sensibles que permitan detectar cantidades bajas del microorganismo en aguas de consumo humano. El estudio de los hábitos de consumo de agua de la población estudiantil de la escuela rural, mostró que más de la mitad de la población consume agua hervida, esto probablemente se deba a que están conscientes que el agua a la cual tienen acceso proviene de una fuente natural no tratada

In order to determine the presence of Blastocystis sp. in drinking water at a rural school in Merida, 36 water samples were collected from natural sources that feed the distribution tank and faucets during the months of September, 2008, February and December, 2009, and May, 2010. Samples were processed using the technique proposed by Suresh et al. (2005). All samples were negative. These results suggest that the water was exempt from Blastocystis or that the quantity of viable cysts present in the samples was very low, not permitting reproduction in the culture. This report suggests the importance of using more sensitive techniques to detect low amounts of the organismin drinking water. The study of student water consumption habits at the rural school showed that more than half the population consume boiled water; probably, they are aware that the water source has not been treated for drinking

Algunas consideraciones acerca de Blastocystissp, un parásito controversial / Some considerations about Blastocystis sp, a controversial parasite / Algumas considerações sobre Blastocystis sp, Um parasita controverso

Blastocystis es un organismo unicelular, anaerobio y uno de los parásitos intestinales de mayor prevalencia a nivel mundial. Durante mucho tiempo su ubicación taxonómica fue difícil de definir. Actualmente es considerado el único parásito humano del Reino Chromista. Se le reconocen numerosas formas evolutivas (vacuolares, granulares, ameboidales, avacuolares, multivacuolares y quísticas) que conforman un ciclo vital aún en estudio. Los quistes son las formas de resistencia y transmisión. Se lo considera un parásito zoonótico con 9 subtipos que pueden tener diferentes especificidades entre hospedadores humanos y animales. Su carácter patógeno ha sido motivo también de controversia dado que puede presentar infecciones asintomáticas o sintomáticas con manifestaciones digestivas, y dérmicas, entre otras. El diagnóstico de laboratorio puede ser microscópico o mediante cultivos, serología y técnicas moleculares.

Blastocystis is an anaerobic, unicellular organism and it is one of the most prevalent among intestinal parasites. It has a worldwide distribution. Nowadays, it is considered the only human parasite that belongs to the kingdom Chromista. Many morphological forms of the parasite are known: vacuolar, granular, amoeboid, avacuolar, multivacuolar and cyst. Its life cycle is not completely understood. Cysts are the forms of resistance and transmission. It is considered a zoonotic parasite with 9 subtypes, with different specificities for human and animal hosts. Its pathogenesis is controversial because it can cause asymptomatic and symptomatic infections, with gastrointestinal and cutaneous manifestations. Laboratory diagnosis may be performed by microscopic, cultural, serological and molecular techniques.

Infecção por Blastocystis hominis e Entamoeba histolytica/Entamoeba dispar em pacientes atendidos em um hospital localizado em Niterói, Rio de Janeiro / Blastocystis hominis and Entamoeba histolytica/Entamoeba dispar infection in patients attended in a Hospital in Niterói, Rio de Janeiro, Brazil

Blastocistose e amebíase são enteroparasitoses causadas pelos protozoários Blastocystis hominis e Entamoeba histolytica/Entamoeba dispar. E. histolytica é a única espécie considerada invasiva. E. dispar é morfologicamente semelhante, mas geneticamente distinta e considerada incapaz de invadir a mucosa intestinal. Um dos aspectos de maior importância na virulência amebiana talvez seja a interação das amebas com a microbiota do intestino do hospedeiro. B. hominis é encontrado com elevada frequência em fezes, assim como sua associação com E. histolytica/E. dispar, sugerindo possível interferência recíproca de patogenicidad. Neste estudo, o objetivo foi demonstrar a frequência de E. histolytica/E. dispar, B. hominis e de sua associação em amostras de fezes de pacientes atendidos no Hospital Universitário Antônio Pedro, entre janeiro e setembro de 2008, por meio de levantamento no livro de registros de resultados de exames parasitológicos de fezes. A frequência global de enteroparasitoses foi de 14,1por cento, sendo B. hominis o mais frequente (6,7por cento), seguido por Entamoeba coli (3,4por cento), Giardia lamblia (2,9por cento) e E. histolytica/E. dispar (2,0por cento). Dos 34 casos positivos para E. histolytica/E. dispar, 20 (58,8por cento) estavam associados com B. hominis. O poliparasitismo (até quatro parasitos na mesma amostra) observado em alguns indivíduos da população estudada sugere possível deficiência de saneamento básico no local de moradia dessas pessoas. O elevado número de casos com associação entre E. histolytica/E. dispar e B. hominis demonstra a necessidade do desenvolvimento de modelos experimentais para o estudo dessa associação in vivo.

Blastocystosis and amebiasis are intestinal parasitoses caused by the protozoan B. hominis and E. histolytica/E. dispar. While E. histolytica is the only species considered invasive, E. dispar is morphologically identical although genetically distinct, and it is considered incapable of invading the intestinal mucosa. One of the most important aspects in the virulence of the ameba might be their interaction with the macrobiota that lives in the host’s intestine. B. hominis is found with highfrequency in feces, and in association with E. histolytica/E. dispar, suggestingpossible reciprocal interference of pathogenicity. The aim of this paper is to show the frequency of E. histolytica/E. dispar, B. hominis and their association on feces samples of patients seen at Hospital Universitário Antônio Pedro (HUAP) in 2008 through a survey of the register of test results for feces samples. The overall frequency of intestinal parasites was 14.1%. B. hominis was the most frequent (6.7%), followed by E. coli (3.4%), G. lamblia (2.9%) and E. histolytica/E. dispar(2.0%). Association with B. hominis was found in 20 (58.8%) of 34 positiveE. histolytica/E. dispar cases. The presence of multiple parasites in the studied population suggests a difficult access to adequate sanitation. The high number of cases with E. histolytica/E. dispar and B. hominis association shows the need to develop experimental models for the study of this association in vivo.

Prevalencia de protozoos intestinales en 79 niños de 2 a 5 años de edad de un hogar infantil estatal en Circasia, Quindío / Prevalence of intestinal protozoa in 79 children 2 to 5 years old from a state nursery program in Circasia, Quindío

Introducción: Los parásitos intestinales se consideran un problema de salud pública en los países en desarrollo y afecta a individuos de todas las edades y sexos, pero se presentan, sobre todo, en los primeros años de vida. En la actualidad, entre las parasitosis más reportadas para el departamento del Quindío se encuentra la giardiasis, producida por Giardia intestinalis (G. duodenalis o G. lamblia), y la blastocistocis, producida por Blastocystis sp. Objetivo: Determinar la prevalencia de protozoos intestinales en 79 niños con edades comprendidas entre los 2 y 5 años, de un hogar infantil en el municipio de Circasia, Quindío.Materiales y métodos: Se recolectaron tres muestras de heces en 79 niños con previo consentimiento del tutor legal. Las muestras fueron sometidas al análisis de laboratorio por examen directo macroscópico y microscópico, utilizando lugol al 1%, solución salina al 0,83%, solución salina-eosina y la técnica de concentración de Ritchie o formol-éter. Resultados: Para los tres muestras, los parásitos con potencial patógeno tuvieron las siguientes prevalencias: Blastocystis sp., 49,4%, 57% y 64,6%; G. lamblia, 16,5%, 22,8% y 15,2 %; complejo Entamoeba histolytica/dispar, 5,1%, 5,1% y 1,3%, respectivamente. Conclusiones: Este estudio muestra la elevada prevalencia de parásitos protozoarios, y Blastocystis sp. fue el más prevalente. Durante el seguimiento se detectó reinfestación de los niños que participaron en el estudio.

Introduction: Intestinal parasites are considered a public health problem in developing countries, and they affect individuals of all ages and sexes; nevertheless they are frequent in early childhood. At present, the most reported intestinal parasite conditions in Quindío are giardiasis, caused by Giardia intestinalis (G. lamblia or G.duodenalis), and blastocystosis caused by Blastocystis sp. Objective: The objective is to determine the prevalence of intestinal parasites in children 2 to 5 years old at a State nursery in Circasia, Quindio. Materials and methods: Three fecal samples per child were collected from 79 children following informed consent from their legal guardians. Microscopic and macroscopic laboratory test were made using 1 % Lugol, 0,8 % saline solution, saline-eosin solution and concentration techniques with formaldehyde-ether (Ritchie.) Results: In the three fecal samples, the pathogen parasites had the following prevalence: Blastocystis sp 49,4 %, 57 % and 64,6 % sp; Giardia lamblia 16,5 %, 22,8 % and 15,2 %; and Entamoeba histolytica/dispar 5,1 %, 5,1 % and.1,3 % respectively.Conclusions: This study shows a high frequency of protozoa parasites, Blastocystis sp being the most prevalent. Re-infection in children was detected during the study.