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PubMed2003

Blastocystis isolates from a pig and a horse are closely related to Blastocystis hominis.

Blastocystis has a widespread distribution in a variety of animals, which is a potential source of infection for humans. However, the contribution of zoonotic transmission remains unclear due to the absence of molecular proof of these organisms being identical to those found in humans. We report herein the similar subgroup of Blastocystis isolates from humans, pigs, and a horse using a restriction fragment length polymorphism (RFLP) analysis of partial small-subunit ribosomal DNA (ssu rDNA). Additionally, sequence and phylogenic analysis of partial ssu rDNA of Blastocystis from a human, a pig, and a horse sharing a common subgroup shows that Blastocystis isolates from a pig and a horse were monophyletic and closely related to B. hominis, with 92 to 94% identity. These results suggest the possibility of zoonotic potential of Blastocystis.

Animals↗

PubMed2002

Epidemiological survey of Blastocystis hominis in Huainan City, Anhui Province, China.

AIM: To provide scientific evidence for prevention and controlling of blastocystosis, the infection of Blastocystis homonis and to study its clinical significance in Huainan City, Anhui Province, China. METHODS: Blastocystis homonis in fresh stools taken from 100 infants, 100 pupils, 100 middle school students and 403 patients with diarrhea was smeared and detected with method of iodine staining and hematoxylin staining. After preliminary direct microscopy, the shape and size of Blastocystis homonis were observed with high power lens. The cellular immune function of the patients with blastocystosis was detected with biotin-streptavidin (BSA). RESULTS: The positive rates of Blastocystis homonis in fresh stools taken from the infants, pupils, middle school students and the patients with diarrhea, were 1.0 % (1/100), 1.0 % (1/100), 0 % (0/100) and 5.96 % (24/403) respectively. Furthermore, the positive rates of Blastocystis homonis in the stool samples taken from the patients with mild diarrhea, intermediate diarrhea, severe diarrhea and obstinate diarrhea were 6.03 % (14/232), 2.25 % (2/89), 0 % (0/17) and 12.31 % (8/65) respectively. The positive rates of Blastocystis homonis in fresh stools of male and female patients with diarrhea were 7.52 % (17/226) and 3.95 % (7/177) respectively, and those of patients in urban and rural areas were 4.56 % (11/241) and 8.02 % (13/162) respectively. There was no significant difference between them (P>0.05). The positive rates of CD(3)(+), CD(4)(+), CD(8)(+) in serum of Blastocystis homonis-positive and-negative individuals were 0.64+/-0.06, 0.44+/-0.06, 0.28+/-0.04 and 0.60+/-0.05, 0.40+/-0.05 and 0.30+/-0.05 respectively, and the ratio of CD(4)(+)/CD(8)(+) of the two groups were 1.53+/-0.34 and 1.27+/-0.22. There was significant difference between the two groups (P<0.05, P<0.01). CONCLUSION: The prevalence of Blastocystis hominis as an enteric pathogen in human seems not to be associated with gender and living environment, and that Blastocystis hominis is more common in stool samples of the patients with diarrhea, especially with chronic diarrhea or obstinate diarrhea. When patients with diarrhea infected by Blastocystis hominis, their cellular immune function decreases, which make it more difficult to be cured.

Adolescent↗

PubMed2004

A survey of Blastocystis infection in anuran and urodele amphibians.

Blastocystis infection in amphibians was surveyed in three species of anuran and one species of urodele amphibians captured at two distinct locations in Japan. All three species of frogs were highly infected with Blastocystis, while 69 individual urodele newts, Cynopus pyrrhogaster, were negative for infection. Eleven Blastocystis isolates (47.8%) were recovered from 23 Rana nigromaculata leopard frogs. Twenty-three (92%) of 25 Rana catesbeiana bullfrogs and all (100%) of 24 Bufo japonicus japonicus toads were positive for Blastocystis. Two distinct populations of the toad and bullfrog showed a high prevalence (100 or 84.6%) of Blastocystis infection, while in two populations of the leopard frog only one population was positive for Blastocystis (84.6%). Three Blastocystis isolates from different species of the frogs were established. Since none of the three isolates could survive at 37 degrees C, a temperature tolerance assay was performed to assess the optimal growth temperature and to determine the range of non-lethal temperatures. During the exponential growth phase of 3- or 4-day cultures at 25 degrees C, three isolates were exposed to 4, 28, 31, or 34 degrees C for 3 days and then returned to 25 degrees C to monitor the cell growth. Based on the optimal growth temperatures and different ranges of temperature tolerance among the three new isolates from frogs and two known species, Blastocystis hominis and Blastocystis lapemi, it was established that the three isolates recovered from different species of frogs had different physiological features from B. hominis and B. lapemi.

Animals↗

PubMed2026

First identification and molecular subtyping of Blastocystis spp. in donkeys in Aksaray province, Türkiye.

Blastocystis is a common intestinal protist worldwide that can infect humans and animals. Although its molecular epidemiology in Türkiye is mostly focused primarily on humans and livestock, equids have received limited attention despite their traditional roles and frequent contact with humans and other animals in rural environments. This study aimed to determine the molecular prevalence and subtype (ST) distribution of Blastocystis spp. in donkeys in Aksaray Province, providing the first molecular data on donkeys in Türkiye. A total of 182 fresh fecal samples were collected from donkeys in nine villages within Aksaray province. Genomic DNA was extracted, and the small subunit ribosomal RNA (SSU rRNA) gene fragment of Blastocystis spp. was amplified via PCR analysis. Positive isolates were sequenced bidirectionally for identification and subsequent phylogenetic analysis of Blastocystis in donkeys. The overall molecular prevalence of Blastocystis spp. in donkeys was 4.4% (8/182). The infection rate was higher in young donkeys (under 3 years old; 8.33%) than in adults (3 years or older; 2.46%). However, this difference was not statistically significant. Sequence analysis of the positive PCR products revealed the presence of one known livestock-specific subtype, ST10. Phylogenetic analysis showed that the ST10 isolates characterized in this study clustered with isolates identified from different hosts. This study provides the first molecular data on Blastocystis presence in donkeys in Türkiye. The exclusive detection of ST10 suggests potential cross-species transmission, likely facilitated by the traditional practice of co-housing donkeys with other animals in confined barns. These findings indicate that donkeys may contribute to Blastocystis transmission, underscoring the importance of a "One Health" approach in future epidemiological surveillance.

Animals↗

PubMed2005

Molecular characterization of Blastocystis isolates in the Philippines by riboprinting.

Extensive genomic polymorphism has been demonstrated among morphologically identical Blastocystis isolates. To this end, 32 Blastocystis isolates from the Philippines (12 from humans, 12 from pigs and 8 from chickens) were analyzed genetically by riboprinting or restriction fragment length polymorphism (RFLP) analysis of polymerase chain reaction (PCR) amplified small subunit rDNA. Three distinct riboprint patterns were observed from the HinfI digestion, while four patterns resulted from the RsaI digestion of Blastocystis SSU rDNA. Restriction fragment profiles between Blastocystis isolates from different hosts were generally different from each other. However, Blastocystis isolates within each host group were practically the same. Cluster analysis of the riboprint patterns revealed seven distinct groups of the Blastocystis isolates, including a zoonotic strain. These results demonstrate the genetic heterogeneity of Blastocystis in the Philippines and a support to the idea of the organism's zoonotic potential.

Animals↗

PubMed2006

Direct characterization of Blastocystis from faeces by PCR and evidence of zoonotic potential.

In vitro propagation followed by PCR, and a PCR-based method capable of the direct detection of Blastocystis in faeces were utilized to detect Blastocystis from various hosts in Australia, including primates and their handlers from the Perth Zoo. In addition, Blastocystis isolates from dogs and humans living in a localized endemic community in Thailand were also characterized genetically. PCR-based detection directly from faeces was shown to be more sensitive compared with in vitro culture for the detection of Blastocystis. Moreover, phylogenetic analysis of Blastocystis isolates amplified utilizing in vitro techniques prior to PCR revealed that this method favoured the preferential amplification of Blastocystis subtype 5 over subtype 1. This study is the first to provide molecular-based evidence supporting the zoonotic potential of Blastocystis in dogs, possums and primates in a natural setting.

Animals↗

PubMed1993

Prevalence and characteristics of Blastocystis hominis infection in children.

Blastocystis hominis, a protozoan whose pathogenicity has been questioned, is sometimes found in the human gastrointestinal tract. We sought to determine the prevalence of Blastocystis in stool and to characterize clinical features of infection with Blastocystis in children. Forty-six (3%) of 1,736 patients undergoing fecal microscopy at Children's Hospital of Pittsburgh between January 1, 1985, and December 31, 1988, harbored Blastocystis. Of these 46 children, 75% had exposure to well water or had been in developing countries. Thirty-nine of the 46 (85%) experienced gastrointestinal symptoms, such as abdominal pain, diarrhea, vomiting, and weight loss. Blastocystis was the only parasite found in 35 of those 39 symptomatic children. Symptoms resolved within one month in 90% of patients receiving antiparasitic pharmacotherapy, but in only 58% (P < .04) of those receiving no therapy. We conclude that children infected with Blastocystis often experience gastrointestinal symptoms and that treatment increases the rate of symptomatic improvement. We speculate that Blastocystis is a human pathogen.

Adolescent↗

PubMed2005

Analysis of the ITS region and partial ssu and lsu rRNA genes of Blastocystis and Proteromonas lacertae.

Blastocystis is a common single-celled enteric parasite found in a large variety of hosts. Recent molecular analysis supports the concept that this eukaryotic organism is a stramenopile most closely related to Proteromonas lacertae, a parasite of reptiles. In this study, the internal transcribed spacer region, partial small subunit rRNA and large subunit rRNA genes from 7 Blastocystis isolates (5 human, 1 pig and 1 sheep), and a Proteromonas lacertae isolate were amplified by PCR, cloned and sequenced. Blastocystis was found to be a typical eukaryote with both ITS1 and ITS2 regions present. Phylogenetic analysis based on the entire PCR amplicon revealed that the Blastocystis isolates did not segregate according to host or geographic origin. The highest sequence identities with the conserved Blastocystis 5.8S rDNA sequence were with the stramenopiles Fibrocapsa japonica, Chattonella marina, Cylindrotheca closterium and Hyphochytrium catenoides. The most parsimonious tree based on the 5.8S rDNA sequence from P. lacertae, 11 other stramenopiles, 2 fungi, 3 algae and 3 alveolates showed Blastocystis positioned within the stramenopiles, with P. lacertae as its closest relative. This work therefore supports the hypothesis that Blastocystis is most closely related to P. lacertae, and that it should be regarded as an unusual stramenopile.

Animals↗

PubMed2006

Blastocystis ratti induces contact-independent apoptosis, F-actin rearrangement, and barrier function disruption in IEC-6 cells.

Blastocystis is an enteric protozoan purportedly associated with numerous clinical cases of diarrhea, flatulence, vomiting, and other gastrointestinal symptoms. Despite new knowledge of Blastocystis cell biology, genetic diversity, and epidemiology, its pathogenic potential remains controversial. Numerous clinical and epidemiological studies either implicate or exonerate the parasite as a cause of intestinal disease. Therefore, the aim of this study was to investigate the pathogenic potential of Blastocystis by studying the interactions of Blastocystis ratti WR1, an isolate of zoonotic potential, with a nontransformed rat intestinal epithelial cell line, IEC-6. Here, we report that B. ratti WR1 induces apoptosis in IEC-6 cells in a contact-independent manner. Furthermore, we found that B. ratti WR1 rearranges F-actin distribution, decreases transepithelial resistance, and increases epithelial permeability in IEC-6 cell monolayers. In addition, we found that the effects of B. ratti on transepithelial electrical resistance and epithelial permeability were significantly abrogated by treatment with metronidazole, an antiprotozoal drug. Our results suggest for the first time that Blastocystis-induced apoptosis in host cells and altered epithelial barrier function might play an important role in the pathogenesis of Blastocystis infections and that metronidazole has therapeutic potential in alleviating symptoms associated with Blastocystis.

Actins↗

PubMed2006

PCR for the identification and differentiation of Histomonas meleagridis, Tetratrichomonas gallinarum and Blastocystis spp.

In the present investigation PCR assays were developed for the rapid detection and differentiation of two poultry flagellates: Histomonas meleagridis and Tetratrichomonas gallinarum as well as the protozoan microorganism: Blastocystis spp. The nucleotide sequences of the small subunit ribosomal RNAs were used for primer construction obtaining fragments which vary in size for each microorganism. The established PCRs were able to detect DNA obtained from one microorganism of T. gallinarum and Blastocystis spp. propagated in vitro, proving the high analytical sensitivity of the method. DNA isolated from 10 protozoa was sufficient to detect H. meleagridis. To assess specificity, each PCR assay was performed with DNA from either H. meleagridis and/or T. gallinarum and/or Blastocystis spp. as well as with DNA from several other protozoan parasites (Eimeria tenella, Toxoplasma gondii, Cryptosporidia spp., Trichomonas gallinae, Entamoeba invadens, Entamoeba ranarum), fungi (Aspergillus fumigatus, Candida albicans), bacteria (Staphylococcae, Streptococcae, E. coli, Clostridium perfringens, Camplyobacter jejuni, Proteus) and viruses (fowl adenovirus serotype 4, avian reovirus) as well as livers and caecal samples from turkeys and specified pathogen free (spf) chickens. No cross-reactions with any of these samples were observed with the primer sets for the detection of H. meleagridis and Blastocystis spp. The primers designed for the identification of T. gallinarum yielded a PCR product with DNA of Trichomonas gallinae that had the identical size as the amplicon obtained with DNA from T. gallinarum. However, no PCR products resulted from any of the other samples tested with these primers. Liver and caecal samples from turkeys and chickens from flocks with outbreaks of histomonosis also named as "histomoniasis" originating from geographically distinct regions were investigated with the established PCRs. This is also the first report about the detection of the nucleic acid of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in the livers and/or caeca of laying hens and turkeys obtained from field outbreaks. Hence, the established PCR assays proved to be a rapid and sensitive diagnostic tool for the direct detection and differentiation of H. meleagridis, T. gallinarum and Blastocystis spp. nucleic acid in organ samples of infected turkeys and chickens regardless of the geographic origin.

Animals↗

PubMed2026

First Report of Enterocytozoon bieneusi, Encephalitozoon spp. and Blastocystis spp. in Hair Goats in Türkiye.

INTRODUCTION: Blastocystis spp., Enterocytozoon bieneusi and Encephalitozoon spp. are prevalent zoonotic gastrointestinal parasites that cause severe diarrhoea and enteric diseases in humans and animals worldwide. This study investigated the molecular occurrence, genetic diversity and zoonotic potential of E. bieneusi, Blastocystis spp. and Encephalitozoon spp. in domestic hair goats in Central Anatolia. METHODS: A total of 300 faecal samples were collected from hair goats in Kayseri, Aksaray and Sivas Provinces and genomic DNA was extracted from these samples. The presence of the three pathogens was detected using PCR and nested PCR targeting the SSU rRNA for Blastocystis spp., the internal transcribed spacer (ITS) for E. bieneusi and Encephalitozoon spp., respectively. Positive PCR products were sequenced to determine the species, subtypes and genotypes of the pathogens. RESULTS: The overall prevalence rates of E. bieneusi and Blastocystis spp. were 5.3% (16/300) and 6.7% (20/300), respectively. None of the faecal samples tested was positive for Encephalitozoon spp. and no co-infections among these three pathogens were detected. The SSU rRNA sequence analysis revealed Blastocystis spp. ST10, a subtype predominantly associated with animals. Additionally, one known E. bieneusi genotype (BEB6) was identified. The BEB6 genotype falls into zoonotic Group 2 of E. bieneusi in the phylogenetic tree. CONCLUSION: Our study is the first report of Blastocystis spp. and E. bieneusi infection in hair goats in Türkiye, highlighting their potential role in zoonotic transmission within a One Health framework. Our results provide scientific data for the prevention and control of these two intestinal pathogens. Further investigations are necessary to better understand their genetic characteristics and zoonotic potential in Türkiye.

Enterocytozoon bieneusi↗

PubMedDate not supplied

DNA polymorphism revealed by arbitrary primers polymerase chain reaction among Blastocystis strains isolated from humans, a chicken, and a reptile.

DNA polymorphisms of different strains of Blastocystis isolated from humans, a chicken, and a reptile were examined by an arbitrary primer PCR method. Two strains of Blastocystis hominis isolated from humans in the USA and Japan yielded nearly identical PCR products. However, one strain of B. hominis (isolated from a human in Singapore) yielded quite different PCR products. Blastocystis sp. isolated from a chicken yielded PCR products similar to those of the former two strains, while Blastocystis lapemi, isolated from a reptile, shared no bands with any of the other isolates. These results indicate the possibility that our isolate from the chicken is a zoonotic strain, and that there is intraspecific variation of Blastocystis hominis.

Animals↗

PubMed1996

Axenic culture of reptilian Blastocystis isolates in monophasic medium and speciation by karyotypic typing.

The growth of axenic reptilian isolates of Blastocystis in Iscove's modified Dulbecco's medium (IMDM) was studied and the morphology of the parasite was examined by phase-contrast microscopy. The chromosomal patterns of these reptilian isolates of Blastocystis were examined by pulsed-field gel electrophoresis (PFGE) and compared with those of B. hominis and B. lapemi, a sea snake Blastocystis. IMDM with 10% horse serum supported excellent growth of the reptilian Blastocystis isolates. The parasites from all the isolates were predominantly vacuolar, but multivacuolar and amoeboid forms were also seen. Amoeboid forms with rather elongate pseudopodia were also observed. There were some differences in size, morphology, and growth characteristics in the different reptilian isolates. The karyotypic patterns of the Blastocystis isolates from tortoise, iguana, and python were distinctly different from one another and from those obtained with B. hominis and B. lapemi. On the basis of the above-mentioned differences in chromosomal patterns, the tortoise, iguana, and python isolates are described as new species, viz., B. geocheloni sp. nov. from Geochelone carbonaria (red-footed tortoise), B. cycluri sp. nov. from Cyclura cornuta (rhino iguana), and B. pythoni sp. nov. from Python reticulatus (reticulated python).

Animals↗

PubMed1999

A survey of Blastocystis in domestic chickens.

The prevalence and morphology of Blastocystis in fresh faecal material from 227 domestic chickens was investigated. A very high prevalence of infection (approximately 95%) was found in chickens from four of the five commercial farms studied. Extremely high numbers of Blastocystis were found in the majority of samples. Blastocystis cells showed considerable variation in size, ranging from approx. 3 microm to approx. 120 microm in diameter. This size range is more extreme than those previously recognised for the organism from chickens. All chickens from one farm appeared free of Blastocystis infection. Most Blastocystis cells appeared to be the vacuolar form, although the shape of the cells and the appearance of the central vacuole contents varied considerably within and among faecal samples. Nuclei showed "spots" of electron-opaque material, generally arranged as a band within the nuclei. Multiple individual cysts within a single outer fibrillar layer were found in addition to single cysts without an encompassing fibrillar layer.

Animals↗

PubMed1991

A Blastocystis species from the sea-snake, Lapemis hardwickii (Serpentes: Hydrophiidae).

Observations were made on Blastocystis isolated from the sea-snake, Lapemis hardwickii. Exponential growth of the organism was observed between 2 and 4 days of culture. Vacuolated, amoeboid and granular forms were observed in cultures, similar to B. hominis. The optimal growth temperature for the sea-snake Blastocystis was 24 degrees C compared with 37 degrees C for B. hominis. The karyotypic patterns of B. hominis and the sea-snake Blastocystis were studied in the clamped homogeneous electric field (CHEF) technique and found to be different. Based on the above differences, the sea-snake Blastocystis was designated as Blastocystis lapemi sp. nov.

Animals↗

PubMed2005

No correlation between clinical symptoms and Blastocystis hominis in immunocompetent individuals.

UNLABELLED: Abstract Background and Aim: Previous reports regarding the clinical significance and pathogenicity of Blastocystis hominis have been contradictory. The aim of this study was to examine the association between Blastocystis and gastrointestinal symptoms in immunocompetent individuals. METHODS: We monitored over 2800 healthy people for a period of 15 months, and took stool specimens during both asymptomatic periods and during periods of gastrointestinal symptoms. RESULTS: After exclusion of individuals who had simultaneous identification of other fecal pathogens, we compared the proportions of asymptomatic versus symptomatic individuals positive for Blastocystis and found no significant difference (P = 0.5). Symptom status did not correlate with parasite abundance. We found that some individuals were likely to have Blastocystis detected during both asymptomatic and symptomatic periods, possibly suggesting carriage of the organism. CONCLUSION: In conclusion, we found no correlation between clinical symptoms and the presence or absence of Blastocystis among this healthy cohort.

Adolescent↗

PubMed2005

Molecular phylogenies of Blastocystis isolates from different hosts: implications for genetic diversity, identification of species, and zoonosis.

Small-subunit (SSU) rRNA gene sequences were obtained by PCR from 12 Blastocystis isolates from humans, rats, and reptiles for which elongation factor 1alpha (EF-1alpha) gene sequences are already available. These new sequences were analyzed by the Bayesian method in a broad phylogeny including, for the first time, all Blastocystis sequences available in the databases. Phylogenetic trees identified seven well-resolved groups plus several discrete lineages that could represent newly defined clades. Comparative analysis of SSU rRNA- and EF-1alpha-based trees obtained by maximum-likelihood methods from a restricted sampling (13 isolates) revealed overall agreement between the two phylogenies. In spite of their morphological similarity, sequence divergence among Blastocystis isolates reflected considerable genetic diversity that could be correlated with the existence of potentially >/=12 different species within the genus. Based on this analysis and previous PCR-based genotype classification data, six of these major groups might consist of Blastocystis isolates from both humans and other animal hosts, confirming the low host specificity of Blastocystis. Our results also strongly suggest the existence of numerous zoonotic isolates with frequent animal-to-human and human-to-animal transmissions and of a large potential reservoir in animals for infections in humans.

Animals↗

PubMedDate not supplied

Blastocystis hominis among food vendors in Xochimilco markets.

Blastocystis hominis is a pathogenic protozoon that lives in the human bowel and causes diarrhea: the mode of transmission is a passive one, through the ingestion of stool-contaminated water or foods that contain infective forms of the parasite. The purpose of this study is to report the prevalence of Blastocystis hominis among food vendors in the markets within the Xochimilco jurisdiction, Mexico City, Mexico. A cross-sectional study was conducted in which food vendors answered an epidemiological questionnaire and underwent a serial stool culture. The frequency of the intestinal parasitoses reported was estimated and an analysis was carried out associating the presence of Blastocystis hominis with socio-economic and hygienic factors using the odds ratio at a 95% confidence interval. The frequency of intestinal parasites and commensals was 50.4%; Blastocystis hominis was found in 48 (41.7%) food vendors. The risk analysis showed that Blastocystis hominis was associated with: male gender, poor personal hygiene habits, personal history of parasitosis, and family history of parasitosis. The prevalence reported is high when compared with other populations studied. The relevance of this report lies on the fact that food vendors handle foods and could transmit the infection to consumers.

Adult↗