Current status of research regarding Blastocystis sp, an enigmatic protist, in Brazil

The present study aimed to evaluate the occurrence of Blastocystis sp. in Brazilian studies over a period of years (2000-2020), as well as point out relevant aspects of this enigmatic organism. We performed a literature search using six sources of international databases. The data were divided into diagnostic by parasitological and molecular techniques, and relevant aspects. After applying the inclusion and exclusion criteria, 52 studies were included in the final analysis. The occurrence of Blastocystis sp. in Brazil ranged from 0.5% to 86.6%, as determined using parasitological techniques. The highest occurrence was in the North (27.3%) and the lowest, in the Midwest region (13.4%). In Brazil, most studies have employed molecular techniques and are concentrated in the Southeast region. The Blastocystis sp. subtype ST3 had the highest average positivity, followed by ST1 and ST2. These findings represent a panorama that reflects the reality of Brazil; thus, we believe that the effectiveness of parasitological diagnosis should be considered with regard to making an appropriate choice of technique for detecting Blastocystis sp. Additionally, we emphasize the importance of further studies in the context of molecular epidemiology with regard to this genus. Blastocystis sp. is not well understood yet, and very little information regarding this genus is available; hence, further research regarding this genus is urgently needed.

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.

Epidemiological and diagnostic features of blastocystis infection in symptomatic patients in Izmir province, Turkey

The aims of this study were to identify Blastocystis subtypes [STs] in a cohort of Turkish patients with various gastrointestinal symptoms using a novel Real Time PCR method developed recently for Blastocystis detection and assess the relationship between Blastocystis STs and patient symptoms. Totally, 617 stool samples of patients with gastrointestinal symptoms were examined with microscopy and inoculated in Jones medium. Blastocystispositive samples were further assessed to identify coinfections with other possible pathogens, including bacteria and viruses. Diagnostic efficacies of microscopy, culture and Real-Time PCR were compared. PCR products were sequenced to identify the subtypes of Blastocystis isolates. Totally 94 [15.24%] samples were positive for Blastocystis after all methods. Among these, 83 of 94 [88.3%] samples were identified with all methods, while 11 were positive only with Real Time PCR. Diarrhea and abdominal pain were the leading symptoms in the patients. The only pathogenic agent identified in 76 of 94 [80.9%] patients was Blastocystis. Subtype 3 was the leading Blastocystis subtype [44.6%], while subtypes 6 and 7 were firstly isolated from symptomatic patients in our region. Comparison of three diagnostic methods indicated Real Time PCR as the most sensitive and specific method. Blastocystis was the only pathogenic agent among symptomatic patients, with subtype 3 being predominant. Patients with subtypes 6 and 7 need further assessments concerning the zoonotic potential of Blastocystis

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.

Padronização do diagnóstico de Blastocystis hominis por diferentes técnicas de coloração / Standardization of Blastocystis hominis diagnosis using different staining techniques

INTRODUÇÃO: O presente trabalho foi realizado no período de março a maio de 2008, com o objetivo de avaliar a eficácia de diferentes técnicas para diagnóstico de Blastocystis hominis em uma amostra da população atendida pelo Laboratório de Biomedicina da Universidade Feevale, Novo Hamburgo/RS. MÉTODOS: Foram estudadas 100 amostras de fezes de crianças e adultos, que foram coletadas e submetidas às técnicas de sedimentação espontânea (HPJ), sedimentação em formol-éter (Ritchie) e de coloração por Gram e May-Grünwald-Giemsa (MGG). RESULTADOS: A presença de Blastocystis hominis foi observada em 40 amostras, quando utilizadas técnicas de coloração (MGG e Gram), enquanto que as técnicas de sedimentação se mostraram menos eficientes (32 amostras positivas para a técnica de Ritchie e 20 amostras positivas para a técnica de HPJ). CONCLUSÕES: Nossos resultados demonstram que o HPJ foi menos eficiente que outros métodos, indicando a necessidade de se incluir na rotina do laboratório técnicas que permitam a identificação deste parasita.

INTRODUCTION: The present study was carried out from March to May 2008, with the aim of evaluating the effectiveness of different techniques for diagnosing Blastocystis hominis in a sample of the population attended at the Biomedicine Laboratory of Feevale University, Novo Hamburgo, Rio Grande do Sul. METHODS: On hundred feces samples from children and adults were evaluated. After collection, the samples were subjected to the techniques of spontaneous sedimentation (HPJ), sedimentation in formalin-ether (Ritchie) and staining by means of Gram and May-Grünwald-Giemsa (MGG). RESULTS: The presence of Blastocystis hominis was observed in 40 samples, when staining techniques were used (MGG and Gram), while sedimentation techniques were less efficient (32 positive samples using the Ritchie technique and 20 positive samples using the HPJ technique). CONCLUSIONS: Our results demonstrate that HPJ was less efficient than the other methods, thus indicating the need to include laboratory techniques that enable parasite identification on a routine basis.

Clinical and epidemiological characteristics of Blastocystis hominis

Blastocystis hominis is an intestinal parasite known since long. It is cosmopolitan and lives in the colon. It is still the subject of controversy regarding its pathogenicity and possibly opportunistic character. We exhibit in this article the results obtained for 4 years on the epidemiological, clinical and biological character and opportunistic Blastocystis hominis, often overlooked in the examination of parasitological laboratories city. This is a retrospective study of 3257 stool examination [PSE], performed in the Mycology Laboratory of Parasitology of the Charles Nicolle Hospital in Tunis over a period of 4 years [January 2005 December 2008]. Detection of Blastocystis hominis has been made by microscopic examination of samples by direct examination and concentration. Blastocystis was found in 7.27% of cases and 48.5% in men. Endolimax nanus is the parasite most frequently associated with Blastocystis [40.4% of cases]. The port was symptomatic in 72.1% of cases, diarrhea is the symptom most often found [27.7%]. There is a seasonal distribution; in fact, it is more frequently diagnosed in summer and autumn. The absence of gravity and the saprophytic nature of this infection do not lead to an indication for treatment even among profoundly immunosuppressed individuals. Only the persistence of clinical disorders associated with the detection of the parasite and in the absence of other micro-organisms and intestinal parasites justifies the treatement. Metronidazole is the molecule used conventionally

Blastocystis subtypes in irritable bowel syndrome and inflammatory bowel disease in Ankara, Turkey

Blastocystis infection has been reported to be associated with irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) and chronic diarrhoea. The availability of data on the subtypes of Blastocystis found in these patient groups would be of interest in understanding the significance of Blastocystis infection in chronic illness. In this study, we identify Blastocystis subtypes found in patients presenting with IBS, IBD, chronic diarrhoea and asymptomatic patients in Ankara, Turkey. Blastocystis was detected in 11 symptomatic patients by microscopy and 19 by stool culture. Stool culture was more sensitive than microscopy in identifying Blastocystis. Using standard nomenclature adopted in 2007, Blastocystis sp. subtype 3 was the most common in all groups, followed by Blastocystis sp. subtype 2. Identical subtypes of Blastocystis are found in patients with IBS, IBD and chronic diarrhoea. These particular subtypes show low host specificity and are carried by humans and some farm animals. The subtypes of Blastocystis that are commonly found in rodents and certain wild birds were not found in these patients. We suggest a model in which the severity of enteric protozoan infection may be mediated by host factors.

In vitro cultivation for detection and phenotypic study of blastocystis spp. in stool samples

Blastocystis spp. is an unusual enteric parasite of human and many animals. Recent observations indicate that humans are hosts to different pathogenic and non-pathogenic genotypes, many of which are zoonotic. The aim of the present study is to determine the usefulness of short term in vitro cultivation of stool samples in detection of Blastocystis spp. over routine techniques. Also to study the different morphological forms and reproductive modes from longer term cultures and stool samples. One hundred stool samples from symptomatic patients were processed for short term in vitro cultivation using Jones'medium. Direct microscopy of culture samples was compared to that of wet preparation and modified trichrome staining of stool samples. Longer term cultivation of Blastocystis positive samples was conducted to study different morphological forms and reproductive modes of the parasite using direct microscopy of stained and unstained samples, ocular micrometer, phase contrast microscopy [PCM] and scanning electron microscopy [SEM]. Short term in vitro cultivation of stool samples significantly increased the recovery of Blastocystis spp. over examination of wet preparation by 42.86% [p=0.0001] and over permanent staining using modified trichrome stain by 28.57% [p=0.000 1]. Examination of stained and unstained samples from stools and longer term cultures of positive samples revealed five different morphological forms; vacuolar, granular and amoeboid, multivacuolar and cyst forms. As regards the reproductive modes of Blastocystis, the present study identified five modes of reproduction from stool and culture samples: binary fission, multiple fission, budding, endodyogeny and plasmotomy. Schizont-like cells were also seen in some stool and culture samples. Short term in vitro culture of stool samples is a highly recommended diagnostic tool for Blastocystis spp. Infection. Long term culture is a useful tool to study different morphological forms and reproductive modes. More studies are required to verif' some reproductive modes of the parasite

Frequency of Blastocystis hominis and other intestinal parasites in stool samples examined at the Parasitology Laboratory of the School of Pharmaceutical Sciences at the São Paulo State University, Araraquara / Freqüência de Blastocystis hominis e outros enteroparasitas em amostras de fezes examinadas no Laboratório de Parasitologia da Faculdade de Ciências Farmacêuticas da Universidade Estadual Paulista, Araraquara

Blastocystis homins is a protozoan that causes an intestinal infection known as human blastocystosis. This infection is diagnosed by means of parasitological examination of stools and by permanent staining techniques. The present study was developed to evaluate the frequency of Blastocystis hominis infection among inhabitants of the Araraquara region, State of São Paulo, and to compare different methods for investigating this protozoan in feces samples. Evaluations on 503 stool samples were performed by means of direct fresh examination and using the techniques of Faust et al., Lutz and Rugai et al. In addition, the iron hematoxylin, trichrome and modified Kinyoun staining techniques were used. Out of the 503 samples examined, 174 (34.6 percent) were found to be positive for the presence of intestinal parasites. The most frequent protozoa and helminths were Entamoeba coli (14.6 percent) and Strongyloides stercoralis (6.7 percent), respectively. Blastocystis hominis was present in 23 (4.6 percent) fecal samples, with a predominately pasty consistency and without characterizing a condition of diarrhea. Despite the low frequency of Blastocystis hominis found in the Araraquara region, compared with other regions of Brazil, it is important to perform laboratory diagnostic tests for this protozoan. Its finding in fecal material is indicative of food and drinking water contamination. Since the transmission route for this parasite is accepted to be oral-fecal, this implies that the population needs guidance regarding hygiene and basic sanitation measures as a means for controlling health problems caused by enteroparasites.

Blastocystis hominis é um protozoário, causador de infecção intestinal denominada blastocistose humana, cujo diagnóstico é realizado pelo exame coproparasitológico e por meio de técnicas de coloração permanente. Este estudo foi desenvolvido para avaliar a freqüência da infecção por Blastocystis hominis em habitantes da região de Araraquara/SP, bem como comparar diferentes métodos para a pesquisa desse protozoário em amostras de fezes. Foram estudadas 503 amostras de fezes submetidas ao exame direto a fresco, às técnicas de Faust e cols, Lutz e de Rugai e cols, além das colorações pela hematoxilina férrica, tricrômio e de Kinyoun modificada. Entre as 503 amostras examinadas, 174 (34,6 por cento) apresentaram-se positivas para a presença de parasitas intestinais. O protozoário e o helminto mais freqüentes foram Entamoeba coli (14,6 por cento) e Strongyloides stercoralis (6,7 por cento), respectivamente. Blastocystis hominis foi observado em 23 (4,6 por cento) amostras fecais com consistência predominantemente pastosa, não caracterizando quadro diarréico. Apesar da baixa freqüência de Blastocystis hominis encontrada na região de Araraquara, comparativamente a outras regiões brasileiras, é importante a realização do diagnóstico laboratorial desse protozoário. O encontro de Blastocystis hominis em material fecal é indicativo de contaminação de alimentos e água de consumo, desde que se admita a rota de transmissão oral-fecal desse parasita, o que implica na orientação da população sobre as medidas de saneamento básico e higiene como meio para se controlar problemas de saúde ocasionados pelos enteroparasitas.

Blastocystis sp. and other intestinal parasites in hemodialysis patients

Chronic renal insufficiency disease (CRI) leads to uremia in hemodialysis patients and induces a state of immunodepression that results in higher frequencies of infections and diarrhea. Hemodialysis patients resident in the city of Campo Mourão, Paraná, Brazil were analyzed from April 2006 through September 2007 for Blastocystis sp. and other intestinal parasites and for associated diarrhea. Fecal samples from 86 hemodialysis patients and 146 healthy (reference) persons were examined by standard methods for detecting ova, larvae and cysts, which included preservation in 10 percent formalin and the Kinyoun method. Thirty-three hemodialysis patients (45.1 percent) and 36 reference individuals (25.7 percent) were found to be parasitized. The differences in the percentages of parasitism and polyparasitism between the reference group and the chronic renal patients was significant (p= 0.0318 and 0.0019, respectively). Blastocystis sp. (18 percent-20.1 percent), Endolimax nana (14 percent-16.3 percent), Cryptosporidium sp. (4 percent-4.7 percent) and Entamoeba coli (4 percent-4.7 percent) were the most frequent protozoa found in the hemodialysis patients. Parasitism was not significantly associated with diarrhea (p=0.9947) or with decreased white blood cell counts (p=0.7046) in these individuals. Because parasitic infections may be an important comorbidity factor in hemodialysis patients, we suggest that parasitological stool examinations, especially for Blastocystis sp. and Cryptosporidium sp., be included in routine medical follow-up examinations of these patients.

comparison of three different methods for the diagnosis of Blastocystis hominis

A total of 950 fresh faecal specimens from outpatients attending Central Lab in Sebha, Libya were examined for Blastocystis hominis using direct smear microscopy, concentration, and short - term in-vitro culture method [Boeck and Drobohlav medium]. Culture method was found to be more sensitive [42.31%] than the direct smear microscopy [26.21%], and faecal concentration [34.10%]. In-vitro cultivation can be used as routine diagnostic method for the detection of Blastocytosis hominis in stool specimens, especially when dealing with patients with gastrointestinal symptoms

Intestinal protozoa and helminths among Terena Indians in the State of Mato Grosso do Sul: high prevalence of Blastocystis hominis

A parasitological survey was carried out among Terena Indians living in the Tereré settlement in the municipality of Sidrolândia, State of Mato Grosso do Sul, Brazil. Single samples of feces from 313 Indians were processed by means of the spontaneous sedimentation method. In the population studied, 73.5 percent were infected with at least one intestinal parasite or commensal. Protozoa predominated. Blastocystis hominis (40.9 percent), Entamoeba coli (33.2 percent) and Entamoeba histolytica/Entamoeba dispar (31.6 percent) were the most common. Bivariate analysis showed that females were generally more infected and presented higher rates of infection by Entamoeba histolytica/Entamoeba dispar and Entamoeba coli. Males were more infected by hookworms and Strongyloides stercoralis than females. The precarious sanitary conditions of the Tereré settlement are probably a contributory factor towards the high prevalence of intestinal protozoa.

Um inquérito parasitológico foi realizado em índios Terena da aldeia Tereré, do município de Sidrolândia, Estado do Mato Grosso do Sul, Brasil. Amostras únicas de fezes de 313 índios foram processadas pelo método de sedimentação espontânea. Na população estudada, 73.5 por cento estavam infectados por pelo menos um parasita ou comensal intestinal. Os protozoários predominaram. Blastocystis hominis (40.9 por cento), Entamoeba coli (33.2 por cento) e Entamoeba histolytica/Entamoeba dispar (31.6 por cento) foram os mais comuns. A análise bivariada demonstrou que as mulheres estavam mais infectadas no geral e apresentavam maior taxa de infecção para Entamoeba histolytica/Entamoeba dispar e Entamoeba coli. Os homens estavam mais infectados por ancilostomídeos e Strongyloides stercoralis que as mulheres. As precárias condições sanitárias da aldeia Tereré são provavelmente um fator contribuinte para a alta prevalência de protozoários.

Observações sobre Blastocystis hominis e Cyclospora cayetanensis em exames parasitológicos efetuados rotineiramente / Observations on Blastocystis hominis and Cyclospora cayetanensis in routine parasitological examinations

Relatamos algumas observações, efetuadas com exames parasitológicos de fezes, em atividades rotineiras: os métodos de Faust e cols e de sedimentação espontânea em água não servem para evidenciação de Blastocystis hominis; foram encontradas expressivas porcentagens de presença desse protozoário, sobretudo quando realizada coloração pela hematoxilina férrica; houve 0,7 por cento de registro de positividade para Cyclospora cayetanensis, sugerindo inclusão habitual de pesquisa, por técnicas apropriadas, de tal parasita.

We report some observations made from routine parasitological examinations on feces. The methods of Faust et al. and of spontaneous sedimentation in water are not enough to identify Blastocystis hominis. Significant percentage presence of this protozoan was found, especially when staining with iron hematoxylin was performed. Cyclospora cayetanensis was found in 0.7 percent of the cases, which suggests that this parasite should also routinely be investigated by appropriate techniques.

Prevalence and clinical features of blastocystis hominis infection among patients in Sebha, Libya

To determine the prevalence and seasonal variation, and to assess the clinical manifestations and treatment of blastocystosis in Libyan patients. Three thousand six hundred and forty five stool samples were screened for Blastocystis hominis using normal saline and iodine solution preparations. The clinical features of 108 patients were described, in whom B. hominis was the only parasite isolated. Fifty symptomatic patients were treated with 1500 mg metronidazole daily for 7 days and their stools were re-investigated for B. hominis. B. hominis was found in 969 [26.58%] of 3645 stool specimens examined. The infection of B. hominis was significantly more [p < 0.05] in summer than in winter over a three year period. In a prospective study of 108 patients, the most common symptoms with stools positive only for B. hominis were diarrhoea [84.94%], abdominal pain [66.66%], flatulence [17.20%] and vomiting [16.12%]. High concentration of B. hominis cells were found more in symptomatic patients than asymptomatic ones [9.20 cells per 40 X field versus 4.06 respectively] with statistically significant differences [p < 0.001]. Patients with B. hominis responded to metronidazole and were fully cured after 7 days. The occurrence of B. hominis infections in outpatients are probably related to weather conditions, with the suggestion that the hot, dry weather of the Sebha region favors the development and transmission of this organism. B. hominis infections might have a role in some pathological conditions, resulting in gastrointestinal symptoms

Elevada prevalencia de blastocystis hominis en manipuladores de alimentos de los mercados públicos de la zona sud de la ciudad de La Paz / A alta prevalência de Blastocystis hominis entre manipuladores de alimentos em mercados públicos na zona sul da cidade de La Paz

Objetivo. Determinar la prevalencia de blastocystis hominis y otros enteroparásitos en manipuladores de alimentos de los mercados públicos de la zona sud de la ciudad de La Paz. Diseño. Descriptivo transversal. Participantes. Manipuladores de alimentos de los mercados: Achumani, Corazón de Jesus, 16 de Julio y la Merced de la ciudad de La Paz. Lugar. Departamento de patología, cátedra de parasitología. Laboratorio de parasitología. Material y Métodos. Se evaluaron318 muestras de heces, correspondientes a 106 vendedores de alimentos, por examen directo, método de concentracíon de Ritchie modificado y sedimentación espontánea en tubo. Resultados. La prevalencia de la protozoosis intestinal fue de 89,6 por ciento. Los protozoos detectados fueron blastocystis hominis, giardia duodenalis, entamoeba coli, chilomastix mesnili, endolimax nana, lodamoeba butschlii y retortamonas intestinalis. B.hominis fue el protozoo mas frecuente (80,2 por ciento). Se destaca la ausencia de helmintos. En las 101 mujeres y 5 varones, se observó que B. hominis fue más común en el rango de edad de 26 a 37 años (31,8 por ciento) ( p)0.05 ). Las secciones de abarrotes, verduras, comida, jugos y otras mostraron prevalencias entre 29,4 por ciento y 12,9 por ciento, sin embargo, no hubo diferencias significativas ( p)0.05 ). De los 85 manipuladores de alimentos infectados con B. hominis, 13 tenían únicamente este parásito y 72 estaban asociados a otras especies. La combinación estuvo representada por dos, tres y cuatro especies diferentes. Las asociaciones más frecuentes y estadísticamente significativas ( p(0.05 ) fueron con los protozoarios, E. coli y Ch. mesnili. Conclusión. Este es el primer trabajo en Bolivia, donde se determina los valores más altos de prevalencia de B. hominis en la población estudiada, lo que indica...

ObjectiveTo determine the prevalence of Blastocystis hominis and other intestinal parasites among food handlers in South markets, La Paz City.DesignCross-sectional descriptive,ParticipantsFood handlers of the Achumani, Corazón de Jesus, 16 de Julio, and la Merced south markets, La Paz City.PlaceDepartment of Pathology, Laboratory of Parasitology.Material and methodsA serial coproparasitological analysis was performed (3 samples) in 106 food handlers (308 samples) were evaluated by direct examination (saline solution and lugol), modified Ritchie, and simple sedimentation in tube.ResultsThe prevalence of intestinal protozoosis was 89,6%. The detected protozoos was Blastocystis hominis, Giardia duodenalis, Entamoeba coli, Chilomastix mesnili, Endolimax nana, Iodomoeba bütschlii. Retortamonas intestinalis. B. hominis was the most frequently detected protozoa (80,2%). There is absence of helminths.In the 101 women and 5 men, B. hominis was more common in the age range from 26 to 37 years (31,8%) (p>0.05).The sections of groceries, vegetables, food, juices and others, showed prevalences between 29,4% and 12,9%, however, no significant differences were found (p>0.05).Of the 85 food handlers infected with B. hominis, 13 had this parasite only, and in 72 cases B. hominis was associated to other species. The combination was of two, three, and four different species. The most frequent and statistically significant associations (p <0.05) were with the protozoa: E. coli and C. mesnili.ConclusionThis is the first time in Bolivia that a highest prevalence of B. hominis is found in a population group, what indicates a high index of fecal contamination.Therefore, this should be a high-priority group to take into account when measures of promoting prevention and control of these parasites are taken in the population, because the food handlers are an epidemically important group for the dissemination of intestinal parasites.

Prevalence of Blastocystis hominis infection in asymptomatic individuals from Bangkok, Thailand.

Fresh stool examination was performed from 2,230 participants who enrolled in annual check-up programs of the Faculty of Medical Technology, Mahidol University in 1999-2000 and 2004. In this study, Blastocystis hominis infection was diagnosed by culturing in Jones' media. A total of 21% of fecal specimens (in 1999-2000) and 13.7% (in 2004) were positive for B. hominis. The vacuolated form was the predominant form found in culture solution after 48 hours of incubation. The distribution of infection was highest between the ages of 21-30 years (p<0.05). There was no significant difference in infection between male and female groups. Other parasites, eg Giardia lamblia, Entamoeba histolytica, Entamoeba coli, Endolimax nana, Trichomonas hominis, Strongyloides stercoralis, Opisthorchis viverrini and Taenia species, were also found by fresh stool examination.

Blastocystis hominis and other intestinal parasites in a community of Pitanga City, Paraná State, Brazil

O presente trabalho foi realizado no período de agosto a outubro de 2004 com o objetivo de se estimar a prevalência de Blastocystis hominis, avaliar a eficácia de diferentes técnicas para o seu diagnóstico assim como estimar a prevalência de outros parasitas intestinais na comunidade de Campo Verde, município de Pitanga. Amostras de fezes de crianças e adultos foram coletadas e submetidas às técnicas de exame direto, de flutuação em solução de sulfato de zinco, de sedimentação em tubo, de sedimentação em formol-éter e de coloração pelos métodos de Kinyoun e de hematoxilina férrica. Protozoários e/ou helmintos intestinais foram detectados em 128 (70,7%) das 181 amostras de fezes analisadas. As espécies mais prevalentes foram Endolimax nana (33,7%); B. hominis (26,5%); Giardia lamblia (18,2%); Entamoeba coli (17,1%); Ascaris lumbricoides (16,6%); Iodamoeba bütschlii (9,4%) e ancilostomídeos (7,7%). B. hominis foi identificado apenas pelas técnicas de exame direto, de sedimentação em formol-éter e de coloração pela hematoxilina férrica, sendo que esta última se mostrou menos sensível que às demais. A alta freqüência de B. hominis evidenciada por este estudo indica a necessidade de se incluir na rotina do laboratório técnicas que permitam a identificação deste parasita.

Elevada prevalência de blastocistose em pacientes do Centro de Saúde de Soledad, Estado Anzoátegui, Venezuela / Blastocystosis: a high prevalence of cases found in patients from Health Center of Soledad, Anzoategui State, Venezuela

Entre 98 exames parasitológicos de fezes de pacientes do Centro de Saúde de Soledad, Anzoátegui, Venezuela, foram encontrados 46 (46,9 por cento) positivos para Blastocystis hominis.

Blastocystis hominis infection in irritable bowel syndrome patients.

Irritable bowel syndrome (IBS) is a functional bowel disorder in which abdominal pain is associated with a defect or a change in bowel habits. Subtle inflammation, especially after infectious enteritis, has been sometimes suspected as one mechanism of pathogenesis. This research was performed (1) to evaluate the prevalence of parasitic infections and (2) the possible association of IBS and parasitic infections. Fifty-nine IBS patients were recruited using symptom-based criteria (Rome Criteria II) with an absence of intestinal parasitic infection by direct smear method. Stool samples of individual patients were examined using 7 methods, ie examination for stool occult blood, simple saline smear method, formalin-ether technique, culture for Blastocystis hominis, modified trichrome stain, modified Ziehl-Neelsen method, and trichrome stain for parasitic and bacterial infections. Of the 59 patients, stool samples of 13 patients (22.1%) were positive for parasites. These were B. hominis (13.6%), Strongyloides stercoralis larvae (1.7%), Giardia lamblia cysts (1.7%), and non-pathogenic protozoa, ie Endolimax nana cysts (5.1%). The prevalence rate of parasitic infections in the control group (20%) was not statistically different from the patients. There was no statistical difference between B. hominis infection in IBS patients and control was found in this study (p = 0.87). In the IBS group, B. hominis infection predominated (13.6%), while other parasitic infections were found in 8.5%. The culture method for B. hominis is more sensitive than the direct (simple) stool smear method, which is the routine diagnostic method in most laboratories. These results were also found in control group.