Recent developments in Blastocystis research

A cross-sectional survey of Blastocystis sp. and Dientamoeba fragilis in non-human primates and their caregivers in Czech zoos

Intestinal protists in the gut microbiome are increasingly studied, but their basic epidemiology is not well understood. We explored the prevalence, genetic diversity, and potential zoonotic transmission of two protists colonizing the large intestine - Blastocystis sp. and Dientamoeba fragilis - in 37 species of non-human primates (NHPs) and their caregivers in six zoos in the Czech Republic. We analyzed 179 fecal samples (159 from NHPs, 20 from humans) by qPCR. Blastocystis sp. was detected in 54.7% (98/179) of samples, in 24 NHP species and in 57.2% of NHP samples (prevalence ranged between 36 and 80%), and in 35% of human samples (prevalence ranged between 0 and 67%). Using next generation amplicon sequencing, nine Blastocystis subtypes (ST1-ST5, ST7, ST8, and two novel subtypes) were identified. The two new Blastocystis subtypes (named ST47 and ST48) were described using Nanopore sequencing to produce full-length reference sequences of the small subunit ribosomal RNA gene. Some subtypes were shared between NHPs and their caregivers, suggesting potential zoonotic transmission. Mixed subtype colonization was frequently observed, with 52% of sequenced samples containing two or more subtypes. Dientamoeba was found only in NHPs with a prevalence of 6%. This study emphasizes the critical role of molecular diagnostics in epidemiological and transmission studies of these protists and calls for further research to better understand their impact on public health.

Existence of Blastocystis infection in bar-headed goose (Anser indicus)

Blastocystis is a common intestinal protist in humans and animals. Currently, Blastocystis infection in bar-headed geese is unknown. To understand the prevalence and distribution of Blastocystis subtypes in bar-headed geese, fecal samples were collected from 358 bar-headed geese in three regions. The total infection rate of Blastocystis in bar-headed in China was 5.9% (21/358), with 5.0% (6/120) in Aba (Ngawa) Tibetan and Qiang Autonomous Prefect, Sichuan province, 11.8% (14/119) in Maqu county, Gansu province, and 0.8% (1/119) in Caohai, Wei ning county, Guizhou province. The differences in prevalence rates by region were statistically significant. Sequences analyses showed that one known subtype (ST7, n = 16) and one potentially novel ST (n = 5) in bar-headed geese were detected in this study. This is the first report on the prevalence and subtype distribution of Blastocystis in bar-headed geese, which will improve our understanding of the epidemiology and public health implications of Blastocystis infection in wild migratory birds.

Intragenomic diversity of the small subunit rDNA gene shows limited impact on the pathogenicity of Blastocystis infection in clinical patients

The clinical significance of Blastocystis sp. remains to be fully elucidated. This study assesses whether Blastocystis subtype diversity can affect the outcome of the infection and the occurrence of clinical manifestations in infected individuals. Stool samples from 219 Blastocystis-positive patients by PCR targeting the ssu rDNA gene were fully genotyped by Sanger sequencing analyses. Co-infections by other parasitic, viral, and bacterial enteropathogens were identified by molecular and culture methods. Sequence analyses revealed the presence of six Blastocystis subtypes including ST1 (21.5 %), ST2 (17.8 %), ST3 (29.7 %), ST4 (22.8 %), ST6 (5.5 %), and ST7 (2.3 %), with a single sample harbouring a ST1+ST3 co-infection (0.5 %). Multivariate risk factor analyses using logistic regression models indicated that neither Blastocystis subtypes nor patient-associated variables including sex, country of origin, travelling history, and presence of nonspecific symptoms were positively associated with a higher likelihood of developing gastrointestinal symptoms (abdominal pain and diarrhoea). However, being of a young age (p-value: 0.003) and experiencing skin pruritus (p-value < 0.001) and eosinophilia (p-value: 0.016) were found to increase the odds of presenting gastrointestinal symptoms. Blastocystis subtypes based on variability within the ssu rDNA gene do not seem to be the main drivers of clinical manifestations in the surveyed clinical population.

Intestinal Blastocystis is linked to healthier diets and more favorable cardiometabolic outcomes in 56,989 individuals from 32 countries

Diet impacts human health, influencing body adiposity and the risk of developing cardiometabolic diseases. The gut microbiome is a key player in the diet-health axis, but while its bacterial fraction is widely studied, the role of micro-eukaryotes, including Blastocystis, is underexplored. We performed a global-scale analysis on 56,989 metagenomes and showed that human Blastocystis exhibits distinct prevalence patterns linked to geography, lifestyle, and dietary habits. Blastocystis presence defined a specific bacterial signature and was positively associated with more favorable cardiometabolic profiles and negatively with obesity (p < 1e-16) and disorders linked to altered gut ecology (p < 1e-8). In a diet intervention study involving 1,124 individuals, improvements in dietary quality were linked to weight loss and increases in Blastocystis prevalence (p = 0.003) and abundance (p < 1e-7). Our findings suggest a potentially beneficial role for Blastocystis, which may help explain personalized host responses to diet and downstream disease etiopathogenesis.

Unveiling Blastocystis epidemiology in Morocco: subtype diversity among clinical patients with and without gastrointestinal manifestations in the Meknes region

Blastocystis is an intestinal protist frequently identified in humans and other animals, though its clinical significance remains controversial. This study aimed to determine the prevalence and genetic diversity of Blastocystis in faecal samples from symptomatic (n = 55) and asymptomatic (n = 50) individuals seeking medical care in Meknes, Morocco. Detection of the protist was accomplished through coproparasitological examination and culture in Jones medium. Culture-positive samples were subjected to molecular analyses (PCR and Sanger sequencing) based on sequences of the small subunit ribosomal RNA gene. Epidemiological questionnaires on demographics and potential risk factors were collected from participating patients. The overall Blastocystis infection rate was 51.4% (54/105), with no differences between symptomatic (52.7%, 29/55) and asymptomatic (50.0%, 25/50) individuals. Sequence analyses identified three Blastocystis subtypes, with ST3 being the most prevalent (42.0%), followed by ST1 (34.0%), and ST2 (12.0%). Regarding intra-subtype diversity, allele 4 was found within ST1; alleles 11/12 and alleles 34/36 (alone or in combination) were identified within ST2 and ST3 respectively. Allele 34 in ST3 (40.8%) and allele 4 in ST1 (34.7%) were the most common genetic variants circulating in the surveyed clinical population. A statistically significant association between ST2 and the presence of flatulence was observed. This is the first study assessing the epidemiology and genetic diversity of Blastocystis sp. in the Meknes region, Morocco.

Molecular characterization and zoonotic potential of Entamoeba spp., Enterocytozoon bieneusi and Blastocystis from captive wild animals in northwest China

BACKGROUND

Parasites Entamoeba spp., Enterocytozoon bieneusi and Blastocystis are prevalent pathogens causing gastrointestinal illnesses in animals and humans. Consequently, researches on their occurrence, distribution and hosts are crucial for the well-being of both animals and humans. Due to the confined spaces and frequent interaction between animals and humans, animal sanctuaries have emerged as potential reservoirs for these parasites. In this study, the wildlife sanctuary near the Huang Gorge of the Qinling Mountains in northwest China is chosen as an ideal site for parasite distribution research, considering its expansive stocking area and high biodiversity.

RESULTS

We collected 191 fecal specimens from 37 distinct wildlife species and extracted genomic DNA. We identified these three parasites by amplifying specific gene regions and analyzed their characteristics and evolutionary relationships. All the parasites exhibited a high overall infection rate, reaching 90.05%. Among them, seven Entamoeba species were identified, accounting for a prevalence of 54.97%, with the highest infection observed in Entamoeba bovis. In total, 11 Enterocytozoon bieneusi genotypes were discovered, representing a prevalence of 35.08%, including three genotypes of human-pathogenic Group 1 and two novel genotypes (SXWZ and SXLG). Additionally, 13 Blastocystis subtypes were detected, showing a prevalence of 74.87% and encompassing eight zoonotic subtypes. All of the above suggests significant possibilities of parasite transmission between animals and humans.

CONCLUSIONS

This study investigated the occurrence and prevalence of three intestinal parasites, enhancing our understanding of their genetic diversity and host ranges in northwest China. Furthermore, the distribution of these parasites implies significant potential of zoonotic transmission, underscoring the imperative for ongoing surveillance and implementation of control measures. These efforts are essential to mitigate the risk of zoonotic disease outbreaks originating from wildlife sanctuary.

Large-Scale Molecular Epidemiological Survey of Blastocystis sp. among Herbivores in Egypt and Assessment of Potential Zoonotic Risk

Given the proven zoonotic potential of the intestinal protozoan Blastocystis sp., a fast-growing number of surveys are being conducted to identify potential animal reservoirs for transmission of the parasite. Nevertheless, few epidemiological studies have been conducted on farmed animals in Egypt. Therefore, a total of 1089 fecal samples were collected from herbivores (sheep, goats, camels, horses, and rabbits) in six Egyptian governorates (Dakahlia, Gharbia, Kafr El Sheikh, Giza, Aswan, and Sharqia). Samples were screened for the presence of Blastocystis sp. by real-time PCR followed by sequencing of positive PCR products and phylogenetic analysis for subtyping of the isolates. Overall, Blastocystis sp. was identified in 37.6% of the samples, with significant differences in frequency between animal groups (sheep, 65.5%; camels, 62.2%; goats, 36.0%; rabbits, 10.1%; horses, 3.3%). Mixed infections were reported in 35.7% of the Blastocystis sp.-positive samples. A wide range of subtypes (STs) with varying frequency were identified from single infections in ruminants including sheep (ST1-ST3, ST5, ST10, ST14, ST21, ST24, ST26, and ST40), goats (ST1, ST3, ST5, ST10, ST26, ST40, ST43, and ST44), and camels (ST3, ST10, ST21, ST24-ST26, ST30, and ST44). Most of them overlapped across these animal groups, highlighting their adaptation to ruminant hosts. In other herbivores, only three and two STs were evidenced in rabbits (ST1-ST3) and horses (ST3 and ST44), respectively. The greater occurrence and wider genetic diversity of parasite isolates among ruminants, in contrast to other herbivores, strongly suggested that dietary habits likely played a significant role in influencing both the colonization rates of Blastocystis sp. and ST preference. Of all the isolates subtyped herein, 66.3% were reported as potentially zoonotic, emphasizing the significant role these animal groups may play in transmitting the parasite to humans. These findings also expand our knowledge on the prevalence, genetic diversity, host specificity, and zoonotic potential of Blastocystis sp. in herbivores.

First molecular characterization of Blastocystis subtypes from domestic animals (sheep and cattle) and their animal-keepers in Ilam, western Iran: A zoonotic concern

A total of 360 fecal samples were randomly collected from 150 cattle, 150 sheep, and 60 humans (30 people with close animal contact and 30 individuals without close animal contact) at 10 farms in Ilam, western Iran from June 2022 to August 2023. All samples were directly examined for Blastocystis by zinc sulfate flotation, followed by microscopic observation. Positive samples were further subtyped using conventional PCR and sequencing methods. A mean prevalence of 5.3% (16/300) was estimated for Blastocystis infection among examined animals, with 6% and 4.7% for cattle and sheep, respectively. Among the people who had close and non-close animal contact, 16.7% (5/30) and 3.3% (1/30) were infected with Blastocystis, respectively (p < 0.05). All 22 positive samples were successfully sequenced at the SSU rRNA locus. Accordingly, Blastocystis isolates infecting domestic animals in Ilam belonged to the four STs (ST1-ST3, and ST10). Of the 16 animal isolates, nine sequences (four ST10, three ST3, and two ST1) were related to cattle, and seven sequences (three ST10, two ST3, and two ST2) were isolated from sheep. Among the six human isolates, ST3 was the most predominant ST, followed by STs 1, 2, 6, and 7 (one case each). Of note, ST1-ST3 were isolated in various farms both from animals and their breeders, which indicates the possible circulation of these STs between animal and human populations.

Marked genetic diversity within Blastocystis in Australian wildlife revealed using a next generation sequencing-phylogenetic approach

Blastocystis is a genus of intestinal stramenopiles that infect vertebrates, and may cause disease of the alimentary tract. Currently, at least 40 genotypes ("subtypes") of Blastocystis are recognised worldwide based on sequence data for the small subunit of the nuclear ribosomal RNA (SSU-rRNA) gene. Despite the numerous studies of Blastocystis worldwide, very few studies have explored Blastocystis in wild animals, particularly in Australia. Here, we used a PCR-based next generation sequencing (NGS)-phylogenetic approach to genetically characterise and classify Blastocystis variants from selected wildlife in the Australian state of Victoria. In total, 1658 faecal samples were collected from nine host species, including eastern grey kangaroo, swamp wallaby, common wombat, deer, European rabbit, canines and emu. Genomic DNA was extracted from these samples, a 500 bp region of the SSU-rRNA gene amplified by polymerase chain reaction (PCR) and, then, a subset of samples sequenced using Illumina technology. Primary PCR detected Blastocystis in 482 of the 1658 samples (29%), with the highest percentage in fallow deer (63%). Subsequent, Illumina-based sequencing of a subset of 356 samples revealed 55 distinct amplicon sequence variants (ASVs) representing seven currently-recognised subtypes (STs) [ST13 (prominent in marsupials), ST10, ST14, ST21, ST23, ST24 and ST25 (prominent in deer)] and two novel STs (ST45 and ST46) in marsupials. Mixed infections of different STs were observed in macropods, deer, emu and canids (fox, feral dog or dingo), but no infection was detected in rabbits or wombats. This study reveals marked genetic diversity within Blastocystis in a small number of species of wild animals in Australia, suggesting complexity in the genetic composition and transmission patterns of members of the genus Blastocystis in this country.

First Molecular Identification and Subtyping of Blastocystis sp. in the Most Consumed Edible Marine Fish of Iran: A Foodborne Concern

PURPOSE

The presence of Blastocystis sp. is commonly observed in humans and different animals, displaying a wide range of genetic variations with the discovery of multiple subtypes (STs). However, the prevalence and distribution of these STs in edible marine fish and marine mammals remain uncertain. This study marks the first survey conducted in Iran and the second global molecular investigation to examine the occurrence and STs distribution of Blastocystis in various species of edible marine fish.

METHODS

This study screened 200 fresh intestinal contents from 10 well-known fish species (Narrow-barred mackerel, Indo-pacific king mackerel, Tigertooth croaker, Silver pomfret, Black pomfret, Longtail tuna, John's snapper, Blackspotted croaker, Four-finger threadfin, and Javelin grunter) in southern Iran, caught in the Persian Gulf. All collected samples were evaluated by microscopy and SSU-PCR methods.

RESULTS

Based on both microscopy and PCR, the overall prevalence of Blastocystis sp. in evaluated fish species was 2% (4/200). In brief, Blastocystis sp. was reported from Narrow-barred mackerel [10% (2/20)], Silver pomfret [5% (1/20)], and Tigertooth croaker [5% (1/20)]. Interestingly, among infected fish species three zoonotic STs (ST1, ST2, and ST7) were identified. ST2 was the most predominant ST [50% (2/4)], followed by ST1 and ST7, one sample each [5% (1/20)].

CONCLUSION

Overall, the prevalence and STs distribution of Blastocystis in edible marine fish along with the possibility of its zoonotic transmission are still open to question and require extensive and more detailed studies.

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.

Blastocystis genetic diversity in animal and human samples from different departments of Colombia using complete sequencing of the 18S rRNA gene (SSU rRNA) by Oxford Nanopore Technologies (ONT)

Blastocystis is an intestinal microeukaryote that has raised attention due to its wide distribution in animals and humans. The risk of zoonotic circulation primarily arises from close contact with infected animals. Therefore, the following study aimed to evaluate the diversity and frequency of Blastocystis subtypes in Colombian human and animal samples using complete sequencing of the 18S rRNA gene. For this purpose, 341 human stool samples and 277 animal fecal samples (from cattle, sheep, goat, pigs, cats, and dogs), were collected from different Colombian regions and analyzed using PCR-based detection and full-length 18S SSU rRNA gene Next-Generation Sequencing (NGS). Among the 618 samples from both hosts, humans and animals, the results revealed widespread Blastocystis frequency, with 48.09% (n = 164) in humans and 31.4% (n = 87) detection in animals. Dogs, cats, sheep, pigs, and wild animals tested positive, aligning with global prevalence patterns. Also, 29 human samples and 23 animal samples were sequenced using ONT technology from which 11 long-read unique sequences were generated and cluster with their compared reference sequences. The subtype distribution varied within hosts, detecting ST1 and ST3 in both human and animal samples. Subtypes ST5, ST10, ST14, ST15, ST21, ST24, ST25 and ST26 were limited to animals hosts, some of which are considered to have zoonotic potential. On the other hand, ST2 was found exclusively in human samples from Bolivar region. Mixed infections occurred in both animal and humans, 60.86% and 27.58% respectively. Moreover, to our knowledge, this is the first study in Colombia identifying ST15 in pigs and ST25 in sheep. The subtypes (STs) identified in this study indicate that certain animals may serve as reservoirs with the potential for zoonotic transmission. The identification of zoonotic subtypes highlights the use of Next Generation Sequencing as the depth and resolution of the sequences increases providing insights into STs of medical and veterinarian significance. It also reveals the coexistence of diverse subtypes among hosts. Further research is essential for understanding transmission dynamics, health implications, and detection strategies for Blastocystis occurrence in animals and humans, mainly associated to the role of animals as reservoirs and their close interaction with humans.

Effects of Lactiplantibacillus plantarum and Lacticaseibacillus paracasei supplementation on the single-cell fecal parasitome in children with celiac disease autoimmunity: a randomized, double-blind placebo-controlled clinical trial

BACKGROUND

Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 positively affect the fecal bacteriome in children with celiac disease autoimmunity after 6 months of supplementation. The aim of the present investigation was to study the effects of Lactiplantibacillus plantarum HEAL9 and Lacticaseibacillus paracasei 8700:2 on the single-cell parasitome, with a primary focus on Blastocystis.

METHODS

Stool samples were collected from 78 Swedish children with celiac disease autoimmunity participating in a randomized, double-blind, placebo-controlled clinical trial to either receive a mixture of supplementation with L. plantarum HEAL9 and L. paracasei 8700:2 (n = 38) or placebo (n = 40). A total of 227 stool samples collected at baseline and after 3 and 6 months of intervention, respectively, were retrospectively analyzed for Blastocystis by quantitative real-time PCR and subtyped by massively parallel amplicon sequencing. Other single-cell parasites were detected by untargeted 18S rDNA amplicon sequencing and verified by real-time PCR. The relation between the parasites and the bacteriome community was characterized by using 16S rDNA profiling of the V3-V4 region.

RESULTS

Three different single-cell protists were identified, of which the highest prevalence was found for Dientamoeba fragilis (23.1%, 18/78 children), followed by Blastocystis (15.4%, 12/78) and Entamoeba spp. (2.6%, 2/78). The quantity of the protists was stable over time and not affected by probiotic intervention (P = 0.14 for Blastocystis, P = 0.10 for D. fragilis). The positivity of the protists was associated with increased bacteriome diversity (measured by multiple indices, P < 0.03). Bacterial composition was influenced by the presence of the protists: positivity of Blastocystis was inversely associated with Akkermansia (at the levels of the genus as well as its family, order, class and phylum); P < 0.002), Faecalibacterium (P = 0.003) and Romboutsia (P = 0.029); positivity of D. fragilis was inversely associated with families Enterobacteriaceae (P = 0.016) and Coriobacteriaceae (P = 0.022) and genera Flavonifractor (P < 0.001), Faecalibacterium (P = 0.009), Lachnoclostridium (P = 0.029), Ruminococcus (P < 0.001) and Granulicatella (P = 0.018).

CONCLUSIONS

The prevalence of single-cell protists is low in children with celiac disease autoimmunity. The colonization was stable regardless of the probiotic intervention and associated with increased diversity of the fecal bacteriome but inversely associated with some beneficial bacteria.

Detection and Molecular Characterization of Blastocystis Species in Polish Soldiers Stationed in the Republic of Kosovo

Blastocystis species (sp.) is one of the less well-understood water- and foodborne protozoa of medical and veterinary importance linked to different gastrointestinal disorders. Soldiers participating in military missions are particularly vulnerable to infection with this protozoa. The present study used molecular methods to detect, identify, and subtype (ST) Blastocystis sp. in Polish soldiers stationed in the Republic of Kosovo. Fecal samples were collected from 192 soldiers on arrival and after four months of stay. After DNA extraction, the barcoding region of the small subunit ribosomal RNA (SSU-rRNA) gene was amplified and sequenced. The DNA of Blastocystis sp. was detected in six (3.13%) and thirty (15.16%) samples in the first and second batch, respectively. Sequencing analysis revealed infections with ST 2, 3, 4, and 7. There was no statistical association between Blastocystis sp. infection and the parasite's ST or the age or rank of soldiers. The results indicate that the visit to a new environment and prolonged stay in the area of military operation in Kosovo resulted in a significant increase in both Blastocystis sp. infections and ST diversity among surveyed soldiers. This shows the need to undertake appropriate countermeasures to reduce Blastocystis infections in the military environment abroad.

Prevalence and Genetic Characterization of Blastocystis in Sheep and Pigs in Shanxi Province, North China: From a Public Health Perspective

Blastocystis is a common zoonotic intestinal protozoan and causes a series of gastrointestinal symptoms in humans and animals via the fecal-oral route, causing economic losses and posing public health problems. At present, the prevalence and genetic structure of Blastocystis in sheep and pigs in Shanxi province remains unknown. Thus, the present study collected 492 sheep fecal samples and 362 pig fecal samples from three representative counties in northern, central and southern Shanxi province for the detection of Blastocystis based on its SSU rRNA gene. The results showed that the overall prevalence of Blastocystis in the examined sheep and pigs were 16.26% and 14.09%, respectively. Sequences analyses showed that four known subtypes (ST5, ST10, ST14 and ST30) in sheep and two subtypes (ST1 and ST5) in pigs were detected in this study, with ST5 being the predominate subtype among the study areas. Phylogenetic analysis showed that the same subtypes were clustered into the same branch. This study reveals that sheep and pigs in Shanxi province are hosts for multiple Blastocystis subtypes, including the zoonotic subtypes (ST1 and ST5), posing a risk to public health. Baseline epidemiological data are provided that help in improving our understanding of the role of zoonotic subtypes in Blastocystis transmission.

Protozoan parasites and free-living amoebae contamination in organic leafy green vegetables and strawberries from Spain

In this study, the presence of Acanthamoeba spp., Blastocystis sp., Cryptosporidium spp., Cyclospora cayetanensis, Entamoeba histolytica, Giardia sp., Toxoplasma gondii and Vermamoeba vermiformis was assessed in organic leafy green vegetables (lettuce, spinach, cabbage) and fruits (strawberry), which are usually consumed raw. A total of 110 organic samples were collected in Valencia (Spain). Protozoa were concentrated before detection by immunofluorescence (Cryptosporidium spp. and Giardia sp.) or real-time qPCR (Acanthamoeba spp., Blastocystis sp., C. cayetanensis, E. histolytica, T. gondii and V. vermiformis). The most abundant protozoa in organic vegetables and berry fruits were Acanthamoeba (65.5%), followed by T. gondii (37.2%), V. vermiformis (17.3%), C. cayetanensis (12.7%), Cryptosporidium spp. (6.8%), Blastocystis sp. (1.8%) and Giardia sp. (1.7%). E. histolytica was not found in any of the organic samples. Thus, results showed that consumers can be exposed to protozoan parasites by consuming organic vegetables and berry fruits. This is the first report in Spain describing the presence of the protozoan pathogens Acanthamoeba spp., Blastocystis sp., C. cayetanensis, T. gondii and V. vermiformis, Cryptosporidium spp. and Giardia sp. in organic fresh produce. The results of this research will help determine the risk of foodborne protozoan parasites on organic leafy greens and strawberries that are available at local markets.

Prevalence, potential risk factors and genetic diversity of Blastocystis in ruminant livestock animals from Penang, Malaysia

Blastocystis is a unicellular, anaerobic protist inhabiting the intestinal tract of diverse animal hosts, including human. Information regarding Blastocystis in small ruminants, namely goats and sheep, is limited globally; thus, this study was carried out to investigate the distribution and determinants of Blastocystis in ruminant livestock animals from Penang, Malaysia. Fecal samples from 127 cattle, 149 goats, and 100 sheep were examined for Blastocystis by in vitro cultivation using modified Jones' medium, while DNA barcoding was used for subtyping. Overall, 23.1% (87/376) of animals screened were positive for Blastocystis sp. The prevalence of infection was significantly higher in goats than in cattle and sheep, while the female gender, semi-intensive farming system, and the Northeast Penang Island district were identified as potential risk factors for Blastocystis infection. Blastocystis sp. ST5, ST14, and ST25 were identified in cattle; ST5, ST10, ST13, and ST14 in goats; and ST4, ST5, ST14, and ST15 in sheep. ST5 and ST14 were found to be the most abundant and widespread subtypes in the study area. To the best of our knowledge, this is the first report of ST4 from sheep and ST13 from goats, thus serving as an update to the host range of Blastocystis sp. ST4 and ST13. The isolation of ST4 and ST5 in this study suggests that ruminant livestock animals could serve as reservoirs of human infection.

Ultra-deep sequencing of Hadza hunter-gatherers recovers vanishing gut microbes

The gut microbiome modulates immune and metabolic health. Human microbiome data are biased toward industrialized populations, limiting our understanding of non-industrialized microbiomes. Here, we performed ultra-deep metagenomic sequencing on 351 fecal samples from the Hadza hunter-gatherers of Tanzania and comparative populations in Nepal and California. We recovered 91,662 genomes of bacteria, archaea, bacteriophages, and eukaryotes, 44% of which are absent from existing unified datasets. We identified 124 gut-resident species vanishing in industrialized populations and highlighted distinct aspects of the Hadza gut microbiome related to in situ replication rates, signatures of selection, and strain sharing. Industrialized gut microbes were found to be enriched in genes associated with oxidative stress, possibly a result of microbiome adaptation to inflammatory processes. This unparalleled view of the Hadza gut microbiome provides a valuable resource, expands our understanding of microbes capable of colonizing the human gut, and clarifies the extensive perturbation induced by the industrialized lifestyle.

Maternal and food microbial sources shape the infant microbiome of a rural Ethiopian population

The human microbiome seeding starts at birth, when pioneer microbes are acquired mainly from the mother. Mode of delivery, antibiotic prophylaxis, and feeding method have been studied as modulators of mother-to-infant microbiome transmission, but other key influencing factors like modern westernized lifestyles with high hygienization, high-calorie diets, and urban settings, compared with non-westernized lifestyles have not been investigated yet. In this study, we explored the mother-infant sharing of characterized and uncharacterized microbiome members via strain-resolved metagenomics in a cohort of Ethiopian mothers and infants, and we compared them with four other cohorts with different lifestyles. The westernized and non-westernized newborns' microbiomes composition overlapped during the first months of life more than later in life, likely reflecting similar initial breast-milk-based diets. Ethiopian and other non-westernized infants shared a smaller fraction of the microbiome with their mothers than did most westernized populations, despite showing a higher microbiome diversity, and uncharacterized species represented a substantial fraction of those shared in the Ethiopian cohort. Moreover, we identified uncharacterized species belonging to the Selenomonadaceae and Prevotellaceae families specifically present and shared only in the Ethiopian cohort, and we showed that a locally produced fermented food, injera, can contribute to the higher diversity observed in the Ethiopian infants' gut with bacteria that are not part of the human microbiome but are acquired through fermented food consumption. Taken together, these findings highlight the fact that lifestyle can impact the gut microbiome composition not only through differences in diet, drug consumption, and environmental factors but also through its effect on mother-infant strain-sharing patterns.

Circulation and colonisation of Blastocystis subtypes in schoolchildren of various ethnicities in rural northern Thailand

Blastocystis is a protist of controversial pathogenicity inhabiting the gut of humans and other animals. Despite a century of intense study, understanding of the epidemiology of Blastocystis remains fragmentary. Here, we aimed to explore its prevalence, stability of colonisation and association with various factors in a rural elementary school in northern Thailand. One hundred and forty faecal samples were collected from 104 children at two time points (tp) 105 days apart. For tp2, samples were also obtained from 15 animals residing on campus and seven water locations. Prevalence in children was 67% at tp1 and 89% at tp2, 63% in chickens, 86% in pigs, and 57% in water. Ten STs were identified, two of which were shared between humans and animals, one between animals and water, and three between humans and water. Eighteen children (out of 36) carried the same ST over both time points, indicating stable colonisation. Presence of Blastocystis (or ST) was not associated with body mass index, ethnicity, birth delivery mode, or milk source as an infant. This study advances understanding of Blastocystis prevalence in an understudied age group, the role of the environment in transmission, and the ability of specific STs to stably colonise children.

Investigation of intestinal parasites by conventional and molecular methods in children with gastrointestinal system complaints

Intestinal parasitic infections are a global health problem that causes morbidity and mortality, especially in children living in rural areas. In this study, stool samples of pediatric patients with gastrointestinal complaints were examined by conventional and molecular methods to determine the prevalence of intestinal parasites. A total of 100 pediatric patients with gastrointestinal complaints and 50 healthy children were included in the study. Stool samples were collected from each child and examined by direct microscopic examination (native-Lugol method), formol-ethyl acetate concentration technique, Kinyoun's acid-fast staining, and Wheatley trichrome staining methods. Real-time PCR was used for the detection of Blastocystis spp. and D. fragilis in the stool samples. Sanger sequencing was used to identify Blastocystis spp. subtypes. One or more intestinal parasites were found in 12% (n = 100) of the patient group and 1% (n = 50) of the control group using conventional techniques. By using real-time PCR, Blastocystis spp. was discovered in 14% (14/100) of the patient group and 8% (4/50) of the control group. There was no significant difference in the frequency of Blastocystis spp. between the two groups. The most prevalent Blastocystis subtype was ST1 and the most frequent allele was a2 among the samples successfully amplified and sequenced. D. fragilis was detected in 17% (17/100) of the patient group and 8% (4/50) of the control group by real-time PCR. The prevalence of D. fragilis was not significantly different between the patient and control groups, as well. Blastocystis spp. and D. fragilis were found in high prevalence in pediatric patients with gastrointestinal complaints in this study. Although the role of these protists as a pathogen in humans is still controversial, it is supposed to the presence of the parasites are associated with gastrointestinal disorders such as diarrhea, abdominal pain, nausea, and vomiting. More case-control studies are needed to understand the pathogenic or commensal role of these parasites on the intestinal microbiota, especially in both patients with gastrointestinal disorders and healthy individuals.

Comparison of various diagnostic techniques for the detection of Blastocystis spp. and its molecular characterisation in farm animals in the United Arab Emirates

Introduction

Blastocystis spp. is a common anaerobic intestinal parasite infecting humans and a diverse range of animals. The aim of the study was to compare different diagnostic methods for the detection of Blastocystis and survey the occurrence of its subtypes in farm animals, namely sheep, cows and camels, in Al-Ain, United Arab Emirates.

Material and Methods

Ninety-seven faecal samples comprised of 69 from sheep, 12 from cows and 16 from camels were submitted to DNA extraction, PCR and sequencing. Blastocystis was screened for microscopically in 65 samples using direct wet-mount, modified acid-fast staining, trichrome staining and in vitro culture techniques.

Results

Fifteen (15.5%) samples were positive by PCR, twelve of which were confirmed by sequencing. Using PCR as a comparison standard, the sensitivity and specificity of the direct wet-mount, modified acid-fast staining, trichrome staining and in vitro culture methods were 40.0% and 78.3%, 40.0% and 83.3%, 80.0% and 80.0%, and 80.0% and 76.7% respectively. Only culture and trichrome tests were significantly associated with PCR (odds ratio (OR) = 13.14; 95% confidence interval (CI): 1.35–127.4; P = 0.007 and OR = 16; 95% CI: 1.63–156.5; P = 0.003, respectively) with trichrome detecting more positive cases than in vitro culture. The subtype (ST)10 was the only one found in all 12 sequenced sheep isolates.

Conclusion

The study corroborated previous data indicating that sheep are the natural hosts for ST10. No zoonotic subtypes nor mixed-subtype colonisation were found. The report also confirmed the superiority of trichrome staining in detecting Blastocystis spp.

First identification of Blastocystis sp. subtypes in Rex rabbits in China

Blastocystis sp. is a common protist that colonizes the intestinal tract in both humans and animals worldwide. A total of 666 fecal samples of Rex rabbits were collected from 12 farms in three administrative regions in Henan, China. Blastocystis sp. was screened and subtyped by PCR amplification of the small subunit ribosomal DNA. The results indicated that 31 (4.7%, 31/666) rabbits were positive for Blastocystis sp. across three farms (25.0%, 3/12). The infection rate of Blastocystis sp. in Rex rabbits was highest in Jiyuan at 9.1% (30/331), followed by Luoyang (0.5%, 1/191), with no positive infections found in Zhengzhou. The Blastocystis sp. infection rate in adults (10.2%, 14/287) was higher than that in young rabbits (4.5%, 17/379) (χ² = 0.0027, P > 0.50). Four Blastocystis sp. subtypes (ST1, ST3, ST4, and ST17) were identified in rabbits in the present study. Among them, the subtypes ST1 (n = 15) and ST3 (n = 14) were dominant, followed by ST4 (n = 1) and ST17 (n = 1). Blastocystis sp. ST1 was the dominant subtype in adult rabbits, and ST3 was the dominant subtype in young rabbits. This study enriches the data on the prevalence and subtype distributions of Blastocystis sp. in rabbits. More studies are needed among humans, domestic animals, and wild animals to obtain a better understanding of their role in the spread of Blastocystis sp.

Phylogenetic relationship of nonmammalian and avian Blastocystis isolates and conventional subtypes

Blastocystis is an intestinal protist commonly identified in human and animal feces. At present, there are 28 proposed subtypes (STs) identified based on the small subunit rRNA gene, 13 of which are found in both humans and animals. In general, nonmammalian and avian groups are infected by the nonmammalian and avian subtypes (NMASTs). However, NMASTs were also isolated from mammalian hosts, suggesting possible cross-contamination and transmission from nonmammalian and avian hosts to other animals and, potentially, humans. Thus, this study determined the possible relationship between NMAST sequences and conventional STs to provide new insights into Blastocystis classification, identification, and epidemiological significance. Phylogenetic trees were constructed using three statistical models, namely, Maximum Likelihood, Neighbor Joining, and Maximum Parsimony, based on the 30 NMAST sequences. The NMAST sequences formed groups clustered closely with other NMAST subtrees. Most sequences of nonmammalian and avian isolates formed distinct monophyletic clades based on their NMAST classification, with some clustering with mammalian and avian STs. These results indicate the close relationship between Blastocystis isolated from mammalian and avian hosts and nonmammalian and avian hosts.

Supplementary Information

The online version contains supplementary material available at (10.1007/s12639-022-01554-7).

Distribution and Phylogenetic Analysis of Subtypes and Alleles of Blastocystis sp. in the Stool Samples Collected from Patients with Gastrointestinal Complaints in İzmir, Turkey

PURPOSE

Blastocystis sp. is one of the most prevalent intestinal protozoa found in humans and many other animals. The present study aimed to examine the distribution and genetic diversity of Blastocystis sp. in stool samples from patients with gastrointestinal complaints in İzmir, Turkey.

METHODS

All stool samples of 439 patients with gastrointestinal complaints were examined by native-Lugol and trichrome staining. To investigate the presence of Blastocystis sp. in stool samples, DNA was isolated, and PCR was performed with the barcode region in the SSU rRNA gene. PCR positive samples were sequenced to identify subtypes and alleles of Blastocystis sp.

RESULTS

The prevalence of Blastocystis sp. was found to be 16.6% (73/439) in patients with gastrointestinal complaints in İzmir, Turkey. Three different Blastocystis sp. subtypes were identified. ST3 (28/55; 51.0%) was the most common subtype followed by ST2 (19/55; 34.5%) and ST1 (8/55; 14.5%). Itching and diarrhea were the most prominent clinical symptoms in Blastocystis sp. positive patients. When clinical symptoms and subtypes were compared, diarrhea was found in 62.5%, 47.4%, and 46.4% of patients with ST1, ST2, and ST3 subtypes, respectively. In addition, itching was found in 37.5%, 32.1%, and 21.1% of patients with ST1, ST3, and ST2, respectively. Six distinct alleles were identified by allele analysis of Blastocystis 18S rRNA gene: allele 4 for ST1, alleles 9, 11, and 12 for ST2, and alleles 34 and 36 for ST3. In this study, Blastocystis sp. was detected in 16 of 21 districts, including the central and rural districts of İzmir. Although ST1 was detected in central districts, it was not found in rural districts.

CONCLUSION

This study provides comprehensive data on the prevalence and molecular epidemiology of the genetic diversity at the level of subtypes and alleles of Blastocystis sp. in different districts of İzmir province in Turkey. To the best of our knowledge, this is the first study which evaluates the distribution of subtypes and alleles of Blastocystis sp. according to PCR and SSU rRNA gene sequencing in patients with gastrointestinal complaints in different districts of İzmir province in Turkey.

Possible microRNA-based mechanism underlying relationship between chronic spontaneous urticaria and Blastocystis

BACKGROUND

Blastocystis spp. has been proposed as a possible cause of extraintestinal clinical signs such as urticaria pathogenesis.

OBJECTIVES

The aim of this study was to investigate the differences between microRNA (miRNA) expression profiles of Chronic spontaneous urticaria (CSU) patients in the presence or absence of Blastocystis spp. as well as healthy controls. Additionally, cellular pathways which are affected in the presence of Blastocystis spp. were identified.

METHODS

Twenty patients diagnosed with CSU were enrolled in the study and divided into equally two groups according to the presence of Blastocystis spp. Besides, six healthy individuals were included in the study. The expression profiles of 372 human-derived miRNAs have been investigated in serum samples from CSU patients and healthy controls with miScript miRNA PCR Array Human miRBase Profiler.

RESULTS

Compared to Blastocystis-negative (BN)-CSU patients, expression of 3 miRNAs (hsa-miR-3183, hsa-miR-4469, hsa-miR-5191) were found to be downregulated by at least two-fold (p < 0.05) in Blastocystis-positive (BP)-CSU patients. Additionally, the miRNA expression profiles of six healthy individuals (n = 3 Blastocystis-positive, n = 3 Blastocystis-negative) were analyzed and it was determined that the expressions of 7 miRNAs (hsa-miR-4661-5p, hsa-miR-4666a-5p, hsa-miR-4803, hsa-miR-5587-5p, hsa-miR-4500, hsa-miR-5680, hsa-miR-382-3p) increased at least 3-fold in the serum of individuals with Blastocystis-positive compared to Blastocystis-negative subjects. Most down-regulated miRNAs, in BP-CSU patients, affect cell adhesion molecules (CAMs), and signaling pathways therefore, Blastocystis spp. presence may influence the clinical presentation of urticaria by leading to unbalanced immunity. In addition, Blastocystis spp. presence may be influenced TGF- β signaling pathway through altered miRNAs and may be laying the groundwork for the development of CSU in healthy individuals.

CONCLUSIONS

As a consequence, this is the first report to show that the miRNA expression profile is affected by the presence of Blastocystis spp. Further miRNA-based studies are needed in order to enlighten the exact underlying molecular mechanisms of the relationship between Blastocystis spp. and CSU.

Molecular characterization of Blastocystis subtypes in symptomatic patients from the southern region of Syria

Blastocystis sp. is an enteric protist found in humans and a wide range of animal hosts. Genetic variations were established among the 38 different subtypes detected so far, 14 of which are commonly found in human and animal hosts. The aim of the present study is to estimate the prevalence of the common Blastocystis subtypes and evaluate the possible correlation with several variables (gender, age, symptoms, domestic animals…), among patients from the southern region of Syria. Fecal samples were collected from individuals suffering from gastrointestinal complaints. Microscopic examination along with genotype analyses using seven pairs of subtype-specific primers was performed. Our results revealed the presence of Blastocystis sp. in 46 isolates out of the 60 samples microscopically studied (76.7%); single infection was detected in 24 isolates whereas co-infection with other protozoa was identified in 22 ones. Molecular detection targeting the SSU rRNA gene revealed a 100% positive presence of Blastocystis sp. in all the samples. Genotyping results detected the presence of five different subtypes (ST1-ST5) with varying proportions. However, ST1 was the dominant subtype observed (66.7%). Mixed subtype infections were found in 9 isolates (15%). Three samples remained undefined, nonetheless. Our statistical results showed no significant correlation between Blastocystis STs infection and the different studied variables. In conclusion, this study provides the first genetic characterization of Blastocystis subtypes prevalence in patients from the southern region of Syria. ST1 distribution was highly predominant. Further molecular studies are needed to estimate the prevalence of Blastocystis sp. infection in other regions in Syria and to understand the epidemiology and sources of transmission to humans.

Prevalence, Subtype Distribution and Zoonotic Significance of Blastocystis sp. Isolates from Poultry, Cattle and Pets in Northern Egypt

Blastocystis sp. is a widespread enteric protozoan that frequently infects human and animal groups. Despite its burden and zoonotic potential worldwide, epidemiological investigations remain limited in animal groups that come in contact with humans. Therefore, the largest survey ever conducted in North Africa was performed in Egypt with the aim to investigate the prevalence and subtype (ST) distribution of Blastocystis sp. in animals. For this purpose, a total of 889 fecal specimens were collected from chickens (217), cattle (373), dogs (144) and cats (155) from six governorates of northern Egypt. These specimens were then screened for the presence of Blastocystis sp. using a quantitative real-time PCR, followed by subtyping the isolates. The overall prevalence of Blastocystis sp. reached 9.2% (82/889), with the highest infection rates reported in chickens (17.0%) and domestic cattle (11.0%), highlighting an active circulation of the parasite in both animal groups. In contrast, the low prevalence in cats (2.6%) and the absence of the parasite in dogs suggested that pets are not natural hosts of Blastocystis sp. ST10 and ST14 were largely predominant in cattle, confirming that both STs represented cattle-adapted STs. The report of one ST3 and one ST4 isolate in this animal group could be explained by an accidental zoonosis from humans to animals. All but one of the subtyped isolates in poultry belonged to ST7, which was considered as an avian ST. The presence of a remaining isolate of ST14 likely reflected a transient infection from contact between birds and cattle feces. The same environmental contamination was also likely the source of the ST14 infection in three of the four positive cats, with the remaining animals infected by ST3 as the result of human-to-animal transmission. These occurrences and subtyping data, combined with those previously collected in the Egyptian population, implies that poultry could play a significant role as reservoir for zoonotic transmission, which would not be the case for cattle and pets.

Global prevalence and subtype distribution of Blastocystis sp. in rodents, birds, and water supplies: A systematic review and meta-analysis

Animals such as rodents and birds may play a key role in the distribution of Blastocystis sp., either as introducers of the parasite into the water or as receptors of an infection already established in the water. Hence, we aimed to evaluate the prevalence and subtype distributions of Blastocystis sp. in rodents, birds, and water supplies at a global scale through a systematic review and meta-analysis approach. The standard protocol of preferred reporting items for systematic reviews and meta-analyses (PRISMA) statements were applied. Eligible prevalence studies on Blastocystis sp. in rodents, birds, and water supplies, published between 1 January 2000 and 20 January 2022 were collected using a systematic literature search in online databases (Scopus and Web of Science) and search engines (PubMed and Google Scholar). Inclusion and exclusion criteria were followed. The point estimates and 95% confidence intervals (CI) were calculated using a random-effects model. The variances between studies (heterogeneity) were computed by I2 index. In total, 20 articles (24 datasets) for birds, 18 articles (18 datasets) for rodents, and 10 articles (12 datasets) for water supply were included for the final meta-analysis. The pooled prevalence of Blastocystis sp. in birds, rodents, and water was estimated to be 29% (95% CI 12-47%), 18% (95% CI 12-23%), and 10% (95% CI 6%-15%), respectively. Considering the subtypes, Blastocystis sp. with subtypes ST7 in birds, ST4 in rodents, and ST1 in water supplies were the highest reported subtypes. The present results highlight the role of birds, rodents, and water as a reservoir for human-infected Blastocystis sp. Therefore, this global estimate could be beneficial for preventive and control measures.

Occurrence, genetic diversity and zoonotic potential of Blastocystis sp. in forest musk deer (Moschus berezovskii) in Southwest China

Blastocystis sp. is a common anaerobic protist with controversial pathogenicity that can infect various animals and humans. However, there are no reports of Blastocystis sp. infections in forest musk deer (Moschus berezovskii). The present study was designed to examine the occurrence, subtype distribution and genetic characterization of Blastocystis sp. in forest musk deer in southwestern China, and to assess the potential for zoonotic transmission. A total of 504 fresh stool samples were collected from captive forest musk deer in four distinct areas of southwestern China. Overall, 14.7% of the forest musk deer (74/504) were found to be infected with Blastocystis sp. The highest occurrence of Blastocystis sp. was observed in Dujiangyan (27.5%), followed by Maerkang (23.3%). The occurrence of Blastocystis sp. was 7.9% and 4.1% in Shimian and Hanyuan, respectively. Significant differences in the occurrence of Blastocystis sp. among different areas were observed (p < 0.05), while we did not observe significant differences among animals of different age and sex (p > 0.05). Two known zoonotic subtypes (ST1 and ST5) and three animal-predominant subtypes (ST10, ST13, and ST14) were identified, of which ST10 was the most common (36/74, 48.6%). Our findings highlight that forest musk deer may be potential reservoirs of zoonotic human Blastocystis sp. infections.

Frequency, spatial distribution, and genetic diversity of Blastocystis among referred individuals to a clinical laboratory: First report of subtype 9 in Brazil

The enteric protist Blastocystis has a worldwide distribution, however its prevalence in the human population is still underestimated, especially in developing countries where proper diagnosis is not performed in the routine of clinical laboratories. In this study, we aimed to assess the frequency, genetic diversity, and spatial distribution of Blastocystis isolates detected in fecal samples referred to a clinical laboratory for routine examination in inner São Paulo State, Brazil. A total of 348 leftover stool samples available for disposal from female and male individuals with age ranging from 3 months to 88 years were analyzed by both microscopic examination and PCR/sequencing of the SSU rRNA gene. The overall frequency of Blastocystis sp. was 31% (108/348), including 20.1% (70/348) and 31% (108/348) by microscopic examination and PCR/sequencing, respectively. Significant association was found only between Blastocystis infection and age, since the highest rate of positive samples was detected among 5-9 years old individuals (p < 0.0001). In addition, spatial distribution revealed a wide distribution of the positive samples, however they were densely concentrated in more populated areas. Seven subtypes were identified, namely ST1 (40.7%), ST2 (9.2%), ST3 (45.3%), ST4 (0.9%), ST6 (1.8%), ST7 (0.9%) and ST9 (0.9%). The intra-subtype analysis revealed a total of 25 different alleles previously reported. Here, the findings lead us to highlight the following aspects: (1) the identification of a ST9 isolate is a relevant finding since it is considered a very rare subtype in human infections as well as this is the first report in Brazil; (2) the high frequency of Blastocystis in fecal samples submitted for examination in a clinical laboratory points to the need to consider its search in routine parasitological examinations, (3) the spatial distribution of Blastocystis infection was not homogeneous but concentrated in more populated areas where the access for population to diagnostic services in healthcare is likely to be easier and, (4) the genetic variability of Blastocystis isolates suggests exposure of inhabitants living in inner municipalities to different sources of contamination involving anthroponotic and zoonotic transmission pathways.

Evaluation of association with subtypes and alleles of Blastocystis with chronic spontaneous urticaria

Blastocystis is a single-celled parasite commonly found in humans and its pathogenic role is still controversial. In recent years, some studies have suggested that Blastocystis may be a possible agent of gastrointestinal and dermatological symptoms such as acute or chronic urticaria, angioedema, rash, itch, palmoplantar, and diffuse pruritus. We aimed to investigate whether there is a relationship between Blastocystis subtypes and alleles in patients with chronic spontaneous urticaria (CSU) as a case-control study. In this study, stool samples were collected from patients with CSU (n=135) and healthy individuals (n=54). The presence of Blastocystis was investigated using the direct saline smear, Lugol's iodine staining, trichrome staining, Jones' medium culture and PCR assays in stool samples and subtypes (STs) were determined by sequencing according to DNA barcoding. The presence of Blastocystis was identified in 30.4% (64/210) the stool samples, including 31.9% (43/135) of the patients with CSU and 14.8% (8/54) of the control group. Moreover, it was found statistically significant the presence of Blastocystis in terms of both groups (p<0.018). ST3 was detected in 45.9% and 62.5 % as the most prevalent subtype the patients with CSU and the control group, respectively. ST1 (18.9%), ST2 (27%) and ST7 (8.1%) was identified in the patients with CSU group. There was no statistically significant correlation between Blastocystis subtypes and both the groups (p<0.240, p<0.323). Allele 4 for ST1; alleles 9, 10, 11 and 12 for ST2; alleles 34, 36 and 38 for ST3; alleles 41 and 101 for ST7 were detected. Allele 34 (ST3) was found significant in the patients with CSU as compared with control group (p<0.020). Moreover, statistically significant association was found between total IgE value and the certain subtypes (ST2 and ST3) (p<0.0001). As a result of this study, the presence of Blastocystis ST3 allele 34 significantly associated with chronic spontaneous urticaria was revealed.

An Association Between Blastocystis Subtypes and Colorectal Cancer Patients: A Significant Different Profile from Non-cancer Individuals

PURPOSE

Blastocystis is a common enteric human parasite of non-conclusive pathogenicity which may be determined by subtype (ST) variation. Colorectal cancer (CRC) is considered one of the primary causes of cancer mortality. Blastocystis ST7 has been shown to reduce beneficial intestinal microbiota and may exacerbate CRC. This study assessed the possible association between Blastocystis STs and CRC in comparison to non-cancer patients.

MATERIAL AND METHODS

A total of 200 fecal samples were obtained from CRC (100) and non-CRC (100) individuals attending Beni-Suef University Hospital, Egypt. Blastocystis was searched for in all samples using microscopy and culturing. Positive subculture samples were genetically sequenced and subtyped using conventional polymerase chain reaction (PCR). Blastocystis STs were determined by sequencing and a phylogenetic tree was created. Related patient characteristics and tumor stages were analyzed for association with presence of Blastocystis.

RESULTS

Blastocystis was identified in 52% and 42% of CRC and non-cancer individuals, respectively. ST1, 2, and 3 were isolated from both cancer and non-cancer individuals; however, for the first time, ST7 was only isolated from CRC stool samples with significant association. Associated patient characteristics were evaluated as predictors.

CONCLUSION

Blastocystosis is highly prevalent in CRC patients, predominantly in the latest CRC grades and stages. To the best of our knowledge, this is the first study to report the identification of Blastocystis ST7 in CRC patients. To determine whether certain STs of Blastocystis are associated with CRC would require further research, including the role played by gut microbiota.

Experimental colonization with Blastocystis ST4 is associated with protective immune responses and modulation of gut microbiome in a DSS-induced colitis mouse model

Background

Blastocystis is a common gut protistan parasite in humans and animals worldwide, but its interrelationship with the host gut microbiota and mucosal immune responses remains poorly understood. Different murine models of Blastocystis colonization were used to examine the effect of a common Blastocystis subtype (ST4) on host gut microbial community and adaptive immune system.

Results

Blastocystis ST4-colonized normal healthy mice and Rag1^−/− mice asymptomatically and was able to alter the microbial community composition, mainly leading to increases in the proportion of Clostridia vadinBB60 group and Lachnospiraceae NK4A136 group, respectively. Blastocystis ST4 colonization promoted T helper 2 (Th2) response defined by interleukin (IL)-5 and IL-13 cytokine production, and T regulatory (Treg) induction from colonic lamina propria in normal healthy mice. Additionally, we observed that Blastocystis ST4 colonization can maintain the stability of bacterial community composition and induce Th2 and Treg immune responses to promote faster recovery from experimentally induced colitis. Furthermore, fecal microbiota transplantation of Blastocystis ST4-altered gut microbiome to colitis mice reduced the severity of colitis, which was associated with increased production of short-chain fat acids (SCFAs) and anti-inflammatory cytokine IL-10.

Conclusions

The data confirm our hypothesis that Blastocystis ST4 is a beneficial commensal, and the beneficial effects of Blastocystis ST4 colonization is mediated through modulating of the host gut bacterial composition, SCFAs production, and Th2 and Treg responses in different murine colonization models.

Supplementary Information

The online version contains supplementary material available at 10.1007/s00018-022-04271-9.

Ultra-deep Sequencing of Hadza Hunter-Gatherers Recovers Vanishing Microbes.. [PMID: 36238714 PMCID: PMC9558438 DOI: 10.1101/2022.03.30.486478]

The gut microbiome is a key modulator of immune and metabolic health. Human microbiome data is biased towards industrialized populations, providing limited understanding of the distinct and diverse non-industrialized microbiomes. Here, we performed ultra-deep metagenomic sequencing and strain cultivation on 351 fecal samples from the Hadza, hunter-gatherers in Tanzania, and comparative populations in Nepal and California. We recover 94,971 total genomes of bacteria, archaea, bacteriophages, and eukaryotes, 43% of which are absent from existing unified datasets. Analysis of in situ growth rates, genetic pN/pS signatures, high-resolution strain tracking, and 124 gut-resident species vanishing in industrialized populations reveals differentiating dynamics of the Hadza gut microbiome. Industrialized gut microbes are enriched in genes associated with oxidative stress, possibly a result of microbiome adaptation to inflammatory processes. This unparalleled view of the Hadza gut microbiome provides a valuable resource that expands our understanding of microbes capable of colonizing the human gut and clarifies the extensive perturbation brought on by the industrialized lifestyle.

Interactions between Blastocystis subtype ST4 and gut microbiota in vitro

BACKGROUND

Blastocystis ST4 is a common protistan parasite of the gastrointestinal tract of humans and a wide range of animals. While it has been suggested that colonization with ST4 is associated with healthy gut microbiota, how ST4 influences the gut microbiota remains poorly studied. This study aimed to examine the interactions between ST4 and several intestinal bacteria using in vitro co-culture systems, and to further investigate the mechanism of interaction and its effect on the epithelial barrier integrity of HT-29 cells.

METHODS

Seven intestinal bacteria Bacteroides fragilis, Bifidobacterium longum, Bacillus subtilis, Bacteroides vulgatus, Escherichia coli, Enterococcus faecalis, and Lactobacillus brevis were co-cultured with Blastocystis ST4 in vitro. Flow cytometry and quantitative reverse-transcription polymerase chain reaction (qRT-PCR) were used to determine the role of reactive oxygen species (ROS) and bacteria oxidoreductase genes, respectively, in response to Blastocystis co-incubation. Transepithelial electrical resistance (TEER) and flux assays were performed to assess the effect of microbiota representatives on the integrity of the intestinal epithelial barrier.

RESULTS

Co-incubation with Blastocystis ST4 showed a beneficial influence on most intestinal bacteria, while ST4 significantly inhibited the growth of B. vulgatus, a common pathogen in the genus Bacteroides. The decrease in B. vulgatus when co-incubated with Blastocystis ST4 was associated with high levels of ROS and the upregulation of oxidative stress-related genes. Furthermore, co-incubation with Blastocystis ST4 was able to protect the intestinal epithelial barrier from damage by B. vulgatus.

CONCLUSIONS

This study demonstrated, for the first time, that Blastocystis ST4 has beneficial effects on intestinal commensal bacteria in vitro, and can inhibit the growth of pathogenic B. vulgatus. Combined with previous microbiome research on ST4, our data suggest that ST4 may be a beneficial commensal.

[Molecular characterization of algerian strains of Blastocysts sp]

INTRODUCTION

Blastocystis sp. is a protozoan that colonizes the gastrointestinal tract of humans and many animals and is currently the most common parasite found in human stools. In some developing countries, its prevalence in study populations may exceed 50%. Morphologically, isolates of Blastocystis sp. found in different hosts are very similar. However, these same isolates show a very high genetic diversity between them and no less than 17 subtypes (or genotypes) have already been identified from molecular data. Genotyping studies have been carried out in many countries around the world and in particular in some Mediterranean countries such as France, spain, Italy, Turkey and Egypt. However, very little genotyping data is available in Algeria. To this end, we conducted the present study to identify and genotype Blastocystis in human and animal stool samples.

PATIENTS AND METHODS

One thousand eight hundred and sixty-nine (1,869) stool samples from kitchen staff as part of the periodic medical check-up, from subjects for the provision of a medical certificate required for the processing of a visa file and from patients with gastrointestinal disorders were examined. In addition to human faeces, animal samples, including 10 poultry, 2 cattle and 2 murine animals were examined. All stools were subjected to direct microscopic examination supplemented by concentration techniques and modified Ziehl Neelsen staining. Molecular characterization of 39 human and 14 animal isolates was performed by sequencing and the resulting sequences compared with those available from GenBank. Sequencing was only contributory for 30 human and 9 animal strains.

RESULTS

Of all human samples examined 284 were positive (15.19%) with a prevalence of 7.38% for Blastocystis. Of the 30 strains that were molecularly characterized, ST3 was predominant (15/30, 50%) followed by ST1 (10/30, 33.33%) and in third place ST2 (4/30, 13.33%). ST4 was identified in only one patient (1/30, 3.33%). The correlation between clinical status and the subtype of Blastocystis identified showed that the number of ST3 was high in asymptomatic subjects (11/15, 73%) compared to symptomatic subjects (4/15, 26.66%), as well as for the ST1 subtype (7/10, 70% versus 3/10, 30%). Conversely, the number of ST2 was higher in subjects with gastrointestinal disorders (3/4, 75%). In addition to human strains, we genotyped 7 avian, 2 murine and 2 bovine strains. Characterization of the avian strains revealed 5 ST6 (71.42%) and 2 ST7 (28, 57%). The murine and bovine strains are identified as ST7 and ST6 respectively.

Detection, Molecular Identification and Transmission of the Intestinal Protozoa Blastocystis sp. in Guinea from a Large-Scale Epidemiological Study Conducted in the Conakry Area

Blastocystis sp. is a single-celled parasite estimated to colonize the digestive tract of 1 to 2 billion people worldwide. Although it represents the most frequent intestinal protozoa in human stools, it remains still under-investigated in countries with a high risk of infection due to poor sanitary and hygiene conditions, such as in Africa. Therefore, the present study was carried out to determine the prevalence and subtype (ST) distribution of Blastocystis sp. in the Guinean population. For this purpose, fecal samples were collected from 500 individuals presenting or not digestive disorders in two hospitals of Conakry. Search for the parasite in stools was performed by real-time PCR targeting the small subunit rDNA gene followed by sequencing of the PCR products for subtyping of the isolates. A total of 390 participants (78.0%) was positive for Blastocystis sp. Five STs were identified in the Guinean cohort (ST1, ST2, ST3, ST4 and ST14) with varying frequency, ST3 being predominant. Among them, ST4 was found in only two patients confirming its global rarity in Africa whereas infections by ST14 were likely the result of zoonotic transmission from bovid. No significant association was detected between Blastocystis sp. colonization or ST distribution and the symptomatic status of Guinean subjects or the presence of digestive symptoms. In contrast, drilling water consumption represented a significant risk factor for infection by Blastocystis sp. Predominance of ST3 coupled with its low intra-ST diversity strongly suggested large-scale human-to-human transmission of this ST within this cohort. In parallel, the highest intra-ST diversity of ST1 and ST2 was likely correlated with various potential sources of infection in addition to anthroponotic transmission. These findings highlighted the active circulation of the parasite in Guinea as reported in some low-income African countries and the necessity to implement prevention and control measures in order to limit the circulation of this parasite in this endemic geographical area.

Presence and significance of intestinal unicellular parasites in a morbidly obese population

BACKGROUND

Obesity is a chronic disease whose pathogenesis has been related to changes in the intestinal microbiota. Yet, the role of protozoa and other unicellular eukaryotic parasites in this microenvironment is still largely unknown. Their presence within the gut ecosystem in obese subjects warrants further study, as well as their influence on the host metabolism and comorbidities.

METHODS

Herein, a single center, cross-sectional study of 104 obese individuals was performed to assess the presence of six intestinal unicellular parasites in stool using a commercially available kit, and to evaluate its relationship with the presence of abdominal symptoms, metabolic comorbidities, variations in body composition and nutritional deficiencies.

RESULTS

The overall parasitic colonization rate was 51%, with Blastocystis sp., identified as the most frequent (44.2%), followed by Dientamoeba fragilis (11.5%) and Giardia intestinalis (8.7%), and significantly related to the consumption of ecological fruits and vegetables. Contrary to what previous studies pointed out, colonization with parasites species was significantly associated with fewer abdominal symptoms and depositions per day. The presence of parasites did not correlate with any nutritional deficiencies nor differences in body composition, while it did with significant lower HOMA-IR levels and a lower trend towards metabolic syndrome.

CONCLUSION

Obese subjects frequently harbor unicellular enteric parasites, apparently without clinical nor nutritional harm. This evidence suggests that carrying these microorganisms, from an endocrinological perspective, has a beneficial effect, especially on insulin resistance and possibly on the development of related comorbidities.

Blastocystis One Health Approach in a Rural Community of Northern Thailand: Prevalence, Subtypes and Novel Transmission Routes

Blastocystis is the most commonly found eukaryote in the gut of humans and other animals. This protist is extremely heterogeneous genetically and is classified into 28 subtypes (STs) based on the small subunit ribosomal RNA (SSU rRNA) gene. Numerous studies exist on prevalence of the organism, which usually focus on either humans or animals or the environment, while only a handful investigates all three sources simultaneously. Consequently, understanding of Blastocystis transmission dynamics remains inadequate. Our aim was to explore Blastocystis under the One Health perspective using a rural community in northern Thailand as our study area. We surveyed human, other animal and environmental samples using both morphological and molecular approaches. Prevalence rates of Blastocystis were 73% in human hosts (n = 45), 100% in non-human hosts (n = 44) and 91% in environmental samples (n = 35). Overall, ten subtypes were identified (ST1, ST2, ST3, ST4 ST5, ST6, ST7, ST10, ST23, and ST26), eight of which were detected in humans (ST1, ST2, ST3, ST4, ST5, ST7, ST10, and ST23), three in other animals (ST6, ST7, and ST23), while seven (ST1, ST3, ST6, ST7, ST10, ST23, and ST26) were found in the environment. In our investigation of transmission dynamics, we assessed various groupings both at the household and community level. Given the overall high prevalence rate, transmission amongst humans and between animals and humans are not as frequent as expected with only two subtypes being shared. This raises questions on the role of the environment on transmission of Blastocystis. Water and soil comprise the main reservoirs of the various subtypes in this community. Five subtypes are shared between humans and the environment, while three overlap between the latter and animal hosts. We propose soil as a novel route of transmission, which should be considered in future investigations. This study provides a thorough One Health perspective on Blastocystis. Using this type of approach advances our understanding on occurrence, diversity, ecology and transmission dynamics of this poorly understood, yet frequent gut resident.

Blastocystis Subtypes and Culture Characteristics of Isolates from Human Stools Related with the Presence of Gastrointestinal Symptoms: A Case-Control Study

PURPOSE

To stablish if Blastocystis subtypes influences gastrointestinal symptoms.

METHODS

Case-control study. We obtained sequencing for Blastocysts subtyping from 13 patients with gastrointestinal symptoms (diarrhea or abdominal pain) and 12 from individuals without symptoms.

RESULTS

12 sequences were from Subtype 2 and one from Subtype 3 in symptomatic individuals and nine samples were from Subtype 1, one from Subtype 2, and two from Subtype 3 in asymptomatic individuals. The prevalence of subtype 2 in symptomatic individuals was vastly different compared to the frequency in asymptomatic individuals (84.6% vs. 16.6%; OR 27.5 95% CI 3.2-233; Fisher exact test p = 0.0010201335). After in vitro culture, 22 isolates were obtained. Significant differences were observed for the 12 isolates from Subtype 2 that get a smaller number of total cells with dominant growth of vacuolar forms, compared with Subtypes 1 and 3, after eight days of culture.

CONCLUSION

Our results suggest that gastrointestinal symptoms in Colombian individuals with Blastocystis infection depend on the infecting subtype with peculiar phenotypic characteristics in in vitro culture.

First report of Blastocystis infection in Pallas's squirrels (Callosciurus erythraeus) in China

Blastocystis, an intestinal anaerobic protist with high genetic diversity, inhabits a variety of hosts worldwide, including rodents. However, there have been few studies on squirrel Blastocystis infections in China to date. Herein, 171 fecal samples from Pallas's squirrels (Callosciurus erythraeus) sold as pets were collected to investigate the prevalence and genetic characteristics of Blastocystis. A total of 10 Blastocystis-positive samples (10/171, 5.9%) were obtained by PCR amplification and DNA sequencing of the barcode region of the SSU rRNA gene. Blastocystis subtype analysis revealed four known subtypes, namely, ST1, ST3, ST5 and ST6, with ST5 and ST6 being predominant. Phylogenetic analysis was performed to identify each subtype. To our knowledge, this study is the first to explore Blastocystis infection in Pallas's squirrels, expanding the host range of this parasite. Moreover, multiple zoonotic subtypes were found in Pallas's squirrels, suggesting that these animals may serve as reservoirs for pathogens of human Blastocystis infections.

Molecular Characterization of Blastocystis from Beef Cattle in Northeastern China

Blastocystis is a common unicellular protist that lives in the intestines of humans and animals. Blastocystis infection and subtypes in cattle have been reported in several regions. However, the information of Blastocystis infection in cattle in China is still largely scant. To assess the prevalence and subtype distribution of Blastocystis in beef cattle in China, 803 fecal samples were collected from beef cattle farms in four cities of Northeast China, and were subjected to an analysis based on small subunit rRNA gene fragment. The overall prevalence of Blastocystis in beef cattle was 2.11% (17/803), with 2.15% in preweaning calves, 1.9% in postweaning calves, and 3.85% in breeding cattle, but absence in adult cattle (p > 0.05). Moreover, five Blastocystis subtypes were identified (ST10, ST21, ST23, ST25, and ST26), among which ST10 and ST26 subtypes were dominant subtypes in beef cattle. Mixed infections were detected in three specimens (ST10/ST25, ST10/ST23/ST25, and ST10/ST26). This is the first report showing Blastocystis infection in beef cattle in Northeast China. In addition, a variety of Blastocystis subtypes are reported in cattle in China for the first time. These results will benefit for better understanding the epidemiology and public health implications of Blastocystis.

Association between Blastocystis sp. infection and immunocompromised patients: a systematic review and meta-analysis

The significance of opportunistic infections in immunocompromised patients and the enigmatic pathogenicity of Blastocystis directed us to conduct the first global systematic review and meta-analysis on Blastocystis prevalence, odds ratios (ORs), and subtypes distribution in various immunocompromised patients (HIV/AIDS, cancer and hemodialysis patients, as well as transplant recipients). The systematic searching procedure was done in Web of Science, PubMed, Scopus, and Google Scholar databases for relevant published literature until November 11, 2020. Random-effects model was utilized to calculate the weighted estimates and 95% confidence intervals (95% CIs). The computed pooled prevalence of Blastocystis inferred from 118 papers (128 datasets) on immunocompromised patients was 10.3% (95% CI: 8.7-12.2%), with 16.1% (95% CI: 11.3-22.2%), 12.5% (95% CI: 8.5-18%), 8.4% (95 % CI: 6.6-10.6%), and 6% (95% CI: 2.6-13.3%) for hemodialysis patients, cancer patients, HIV/AIDS patients, and transplant recipients, respectively. Based on 50 case-control studies (54 datasets), the highest ORs were associated with cancer [2.81 (95% CI: 1.24-6.38, P = 0.013)] and hemodialysis patients [2.78 (95% CI: 1.19-6.48, P = 0.018)]. The most frequent subtype being found in immunocompromised patients was ST3 [41.7% (95% CI: 31.4-52.7%)], followed by ST1 [31.7% (95% CI: 23.2-41.8%)] and ST2 [23.1% (95% CI: 14.8-34.1%)]. Also, the weighted frequency of Blastocystis in various subgroups (publication year, WHO regions, geographical distribution, continents, and country income) was analyzed separately. In total, the results of the present meta-analysis highlighted that one's immunodeficiency status is probably associated with an increased Blastocystis infection, underpinning strict preventive measures to be taken.

Occurrence and molecular characterization of Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. in captive wild animals in zoos in Henan, China

BACKGROUND

Captive wild animals in zoos infected with Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. can be sources of zoonotic infections and diseases. Therefore, to investigate the distribution of these pathogens in captive wild animals of zoos in Henan, China, a total of 429 fresh fecal samples were collected from six zoos in Henan, China. The infection rates of Cryptosporidium spp., G. duodenalis, E. bieneusi, and Blastocystis sp. were determined by PCR analysis of corresponding loci. Positive results for Cryptosporidium (C. parvum and C. hominis) were subtyped based on the (gp60) gene.

RESULTS

The overall prevalence was 43.1% (185/429), and the prevalence of Cryptosporidium, Giardia duodenalis, Enterocytozoon bieneusi, and Blastocystis sp. were 2.8% (12/429), 0.5% (2/429), 20.8% (89/429), and 19.1% (82/429), respectively. Five Cryptosporidium species, namely, C. hominis, C. parvum, C. muris, C. andersoni, and C. macropodum, were identified in this study. Cryptosporidium parvum was further subtyped as IIdA19G1. Two Giardia duodenalis assemblages (A and E) were also identified. A total of 20 Enterocytozoon bieneusi genotypes were detected, including 18 known (BEB6, D, HND-1, CD7, SDD1, Henan-IV, KIN-1, CHK1, Peru8, Henan-V, CHG11, CHG-1, CHS9, CHG21, Type-IV, CHC9, CM5, and CHB1) and 2 novel genotypes (CHWD1 and CHPM1). A total of nine subtypes of Blastocystis sp. (ST1, ST2, ST3, ST5, ST6, ST7, ST10, ST13, and ST14) were identified in captive wild animals in zoos in the present study. Cryptosporidium andersoni, nine Enterocytozoon bieneusi genotypes, and five Blastocystis subtypes were here first identified in new hosts.

CONCLUSIONS

Our study has expanded the host ranges of these four pathogens. The data indicate that animals in zoos can commonly be infected with these four zoonotic pathogens, and animals in zoos are potential sources of zoonotic infections in humans.

Comparative study of the intestinal parasitism profiles between communities across the 5 municipalities of the Barranquilla metropolitan area, Colombia

OBJECTIVE

The aim of this study was to compare the rate of parasitism and intestinal parasitism profiles of children who live in relatively proximal communities across the 5 municipalities of the Barranquilla metropolitan area, Colombia.

METHODS

In total, 986 fecal samples from children aged 1 to 10 were analyzed using a direct method (physiological saline and lugol) and the zinc sulfate flotation technique. A comparative analysis of the parasitism profiles between sampling locations (7 schools and 3 health centers providing growth and development services) was conducted using principal component analysis (PCA). The presence of Taenia solium antibodies was evaluated by the enzyme-linked immunosorbent assay method in 269 serum samples from the same group of children.

RESULTS

The overall prevalence of intestinal parasitism was 57.6% (range, 42.1%-77.6%) across the sampling areas. The prevalence of helminthiasis was between 4.1% and 23.7%, and that of intestinal protozoa was between 38.2% and 73.5%. PCA showed that the parasite profiles of each sampling location shared no common characteristics. A total of 3.0% of the serum samples were positive for T. solium antibodies.

CONCLUSION

The intestinal parasitism profiles between relatively proximal sampling locations with similar geographic conditions were vastly different, indicating the need to study each small ecological niche on a localized scale to develop more cost-effective interventions for controlling intestinal parasitism.

Molecular Characterization of Blastocystis from Animals and Their Caregivers at the Gdańsk Zoo (Poland) and the Assessment of Zoonotic Transmission

Blastocystis is a highly genetically diverse gut protist commonly found in humans and various animals. The role of animals in human infection is only partly understood. The aim of this study was to determine the host specificity and possibility of zoonotic transmission of this microorganism. Subtypes of Blastocystis isolated from 201 zoo animals and their 35 caregivers were identified by sequencing of the SSU rRNA gene. Blastocystis was found in 26.86% of animal and 17.14% of human samples. Both mammalian (ST1-ST3, ST5, ST8, ST10, ST13, ST14) and non-mammalian subtypes were detected. Of the subtypes found in non-human primates (ST1, ST2, ST3, and ST13), two subtypes (ST1 and ST3) were also detected in humans. The presence of identical ST1 sequences in three monkeys and their caregiver indicates the possibility of direct transmission of Blastocystis between these animals and humans. Detection of ST5 only in wild boars and peccaries, ST8 only in Marsupial, ST10 and ST14 only in Bovidae, and non-mammalian subtypes in reptiles suggests higher host specificity for these subtypes, and indicates that their transmission between animals and humans is unlikely. Additionally, this was probably the first time that ST5 was found in peccaries, ST2 in patas monkeys, and ST8 in red kangaroos.

The neglected role of Blastocystis sp. and Giardia lamblia in development of irritable bowel syndrome: A systematic review and meta-analysis

The possible role of Blastocystis sp. and Giardia lamblia infections in the development of irritable bowel syndrome (IBS) has long been controversial. In this study, we conducted a systematic review and meta-analysis to investigate whether these protozoan infections are associated with IBS development. We systematically searched international databases for all studies that reported these protozoa in IBS patients published by May 10, 2021. Studies were included in the review if they were observational studies with confirmed patients with IBS (in case-control and cross-sectional studies) or parasitic infections (cohort studies) with an appropriate control group. Pooled odds ratios (ORs) and 95% confidence intervals were estimated using a random-effects meta-analysis model for included studies. A total of 32 papers (42 datasets), including 29 papers (31 datasets) for Blastocystis sp./IBS and 11 papers (11 datasets) for G. lamblia/IBS met the eligibility criteria. Our results indicated that the individuals with Blastocystis sp. infection were significantly at a higher risk of IBS development (OR, 1.78; 95%CI, 1.29-2.44). Moreover, cohort studies indicated a significant positive association between G. lamblia infection and IBS risk (OR, 5.47; 95%CI, 4.23-7.08); while an increasing but no statistically significant risk was observed in case-control studies (OR, 1.19; 95%CI, 0.75-1.87). Our findings suggested that Blastocystis sp. and G. lamblia infections are associated with the increased risk of developing IBS. Despite these results, further studies are needed to determine the effect of these protozoa on IBS development.

Prevalence and Subtype Distribution of Blastocystis sp. in Diarrheic Pigs in Southern China

Blastocystis sp. is a common pathogen that infects the intestines of humans and animals, causing a threat to public health. However, little information on the prevalence and subtypes of Blastocystis sp. in diarrheic pigs in China is available. Herein, 1254 fecal samples were collected from diarrheic pigs in 37 intensive pig farms in Hunan, Jiangxi, and Fujian provinces in southern China, and the prevalence and subtypes of Blastocystis sp. were investigated. Blastocystis sp. was detected by PCR assay, which amplified the small subunit rRNA (SSU rRNA) gene. Overall prevalence of Blastocystis sp. was 31.4% (394/1254), including 21.5% (66/307), 33.1% (99/299), 58.9% (56/95), and 31.3% (173/553) in suckling piglets, weaned piglets, fattening pigs, and sows, respectively. Moreover, age and region factors were significantly related to prevalence of Blastocystis sp. (p < 0.05). Four Blastocystis sp. subtypes were identified, including ST1, ST3, ST5, and ST14. The preponderant subtype was ST5 (76.9%, 303/394). To our knowledge, ST14 was firstly found in pigs in China. The human-pathogenic subtypes (ST1, ST3, ST5, and ST14) that were observed in this study indicate a potential threat to public health. These findings provided a new sight for studying the genetic structure of Blastocystis sp.

Global prevalence, subtypes distribution, zoonotic potential, and associated risk factors of Blastocystis sp. in domestic pigs (Sus domesticus) and wild boars (Sus scrofa): A systematic review and meta-analysis

The intestinal parasite Blastocystis sp. is a widely distributed protist among humans and various animal hosts, with significant prevalence in developing countries. Due to the zoonotic nature of its subtypes (STs), we aimed at global estimation of the prevalence, STs distribution, zoonotic potential, and associated risk factors of Blastocystis sp. infection in domestic pigs (Sus domesticus) and wild pigs/wild boars (Sus scrofa). The study was designed and conducted in 2021 via searching articles in PubMed, Scopus, Google Scholar, and Web of Science databases, based on the PRISMA checklist, and meta-analysis was done using a random-effects model to calculate the weighted estimates and 95% confidence intervals (95% CIs). Totally, 43 papers (47 datasets) reported data on 7977 examined pigs in 24 countries with a total prevalence of 50.9% (95% CI: 42.8-59%). In details, prevalence was higher among domestic pigs [52.4% (95% CI: 43.9-60.7%)] than wild boars [31.2% (95% CI: 11.2-62%)], but is poorly statistically supported as far as the CIs largely overlap. Out of 28 reported STs, nine (ST1-ST7, ST10, and ST15) were reported from domestic pigs, while six (ST1, ST3-ST5, ST8, and ST15) had been isolated from wild boars. Among nine zoonotic STs (ST1-ST8, and ST12), all were identified in examined swine populations, except for ST12. As well, ST1 and ST5 were probably the most frequently circulating STs among these animals. In addition, male and older pigs showed higher Blastocystis sp. infection. Altogether, Blastocystis epidemiology and the distribution of its related STs in pigs is still open to question and requires more extensive studies, especially in the neglected regions of the world.