Genetic diversity of Blastocystis in non-primate animals

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.

Prevalence and subtypes of Blastocystis in wild rodents from three provinces in China

Introduction

Blastocystis is one of the most critical intestinal protozoans in various hosts, including humans and mice. To determine the status of Blastocystis infection in wild rodents in China.

Methods

A total of 344 faecal samples were collected from seven wild rodent species from three provinces, and the small subunit ribosomal RNA (SSU rRNA) genes of Blastocystis were amplified to determine their prevalence and subtypes.

Results

Of the 344 samples, 54 (15.70%) were detected as Blastocystis-positive. The prevalence of Blastocystis was 26.14% (40/153), 7.95% (7/88), and 6.80% (7/103) in wild rodents from Hunan Province, Yunnan Province, and Guangxi Province, respectively. The prevalence of Blastocystis in different wild rodent species varied from 0.00% (0/13) in Mus musculus to 40.00% (2/5) in Rattus rattus sladeni. The prevalence of Blastocystis in samples from the lake beach area (27.40%, 40/146) was significantly higher than in those from the mountain (6.80%, 7/103) and field regions (7.37%, 7/95). The prevalence in different seasons was 26.14% in summer (40/153), 7.95% in autumn (7/88), and 6.80% in winter (7/103). Moreover, a total of two Blastocystis subtypes were identified in the investigated wild rodents, including ST4 and ST5.

Discussion

The present study discovered the existence of Blastocystis infection in Rattus favipectus, Microtus fortis, Apodemus agrarius, Bandicota indica, Rattus rattus sladeni, and Rattus losea, expanding the host range of this parasite. The findings also demonstrate that wild rodents may be an important potential infection source for Blastocystis infection in humans and other animals.

Blastocystis colonization and associations with population parameters in Thai adults

BACKGROUND

Blastocystis is a unicellular eukaryote commonly found in the intestinal tract of humans and other animals. The prevalence of Blastocystis has been investigated in both developed and developing countries, yet its occurrence and distribution in rural locations has been less studied. Herein, we aimed to examine the distribution of Blastocystis colonization in Thai adults representing background populations along a rural/peri-urban gradient, as well as associations between colonization and personal characteristics.

METHODOLOGY

A total of 238 participants were recruited from rural and peri-urban areas situated in three provinces. The presence of Blastocystis in feces was evaluated using PCR and qPCR. Information on gender, age, region (province), rural/peri-urban location, and body mass index (BMI) was collected.

PRINCIPAL FINDINGS

The overall rate of Blastocystis carriage was 67.2%. Univariate analysis revealed significant associations between Blastocystis carriage and region (p<0.05), location (p<0.001) and age group (p<0.05). Logistic regression analysis revealed that rural/peri-urban location and BMI were significantly associated with Blastocystis carriage. Nine subtypes (ST1-ST7, ST10 and ST23) were identified with ST3, ST7 and ST1 as the most abundant ones, in this order. The greatest diversity of subtypes, in terms of numbers, was found in the middle aged group (nine subtypes), while the least diversity was found in the young adult and obese (three subtypes each) groups.

CONCLUSIONS

This study increases the understanding of the epidemiology of Blastocystis colonization and its association with population parameters and characteristics in middle-income countries.

New Haplotypes of Blastocystis sp. Identified in Faeces from Various Animal Groups in Algeria

PURPOSE

Blastocystis sp. is a single-celled, anaerobic, parasitic protozoan commonly found in the intestinal tract of animals and humans globally. Genetic analysis has revealed significant diversity within its species, leading to the identification of at least 40 subtypes (ST1-ST40). This study aimed to identify and differentiate Blastocystis in faeces samples from various animal hosts in Algeria.

METHODS

A total of 403 fecal samples, collected from both domestic and zoo animals, were subjected to PCR amplification and sequencing of Blastocystis-specific small subunit ribosomal RNA (SSU-RNA) gene.

RESULTS

The overall prevalence of Blastocystis in animals was found to be 38.9%. Through comprehensive phylogenetic and phylogeographic analyses, we identified four distinct subtypes (ST1 in both domestic and zoo animals, and ST3, ST4, and ST5 exclusively in zoo animals), encompassing nine different haplotypes, including five that appear original to Algeria.

CONCLUSION

This study represents the first epidemiological molecular investigation of Blastocystis sp. in animals in Algeria.

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.

Molecular Prevalence and Subtypes Distribution of Blastocystis spp. in Humans of Latin America: A Systematic Review

Blastocystis spp. are among the few enteric parasites with a prevalence that can reach up to approximately 80% in communities of developing countries. This systematic review updates and summarizes available literature on the molecular prevalence and subtype distribution of Blastocystis spp. in Latin American people. This work follows the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The literature revised covers from 1 January 2015 to 6 October 2023 in seven different scientific databases, and the material was selected through inclusion and exclusion criteria. According to data found in the 36 selected articles, the prevalence of Blastocystis spp. in Latin America ranged between 5.8% (Bolivian rural communities) and 94.0% (Colombian general public). Generally, genomic DNA was extracted from approximately 200 mg fecal sediments using commercial kits, such as the QIAamp Stool Mini Kit (QIAGEN, Hilden, Germany) or the Norgen Stool DNA Isolation Kit (Norgen Biotek Corporation, Thorold, ON, Canada). Subtype-specific primers (such as the couple of primers BhRDr-RD5) developed from unique sequences of the SSU rRNA gene were applied to Blastocystis subtyping. Ten specific subtypes (STs) were found as well as various mixed infections, and the most circulating Blastocystis STs were in the order ST3, ST1, ST2, and ST4. The most recent data about Blastocystis spp. molecular epidemiology and the STs in communities of Latin America are limited to studies from specific countries. Novel scientific data from the other countries are required to obtain a complete picture and truly understand the distribution and prevalence of Blastocystis spp. and the STs.

Monitoring potentially pathogenic protists in sewage sludge using Metataxonomics

Intestinal parasites continue to pose a significant threat to human health worldwide, particularly among children. Contaminated water and soil serve as major transmission vehicles for these parasites and intestinal protists are among the most prevalent parasites in both developed and developing nations. Traditionally, parasites have been studied using human or animal fecal samples, while studying them in environmental samples has been challenging due to technical limitations. However, advancements in Next-Generation Sequencing (NGS) and bioinformatic approaches now enable the detection of parasite DNA in environmental samples. In this study, we applied a metataxonomic and phylogenetic strategy to detect and classify DNA of protists present in sewage sludge from two major cities in Colombia: Medellin and Cali. We successfully detected several human pathogenic parasites including Giardia intestinalis, Entamoeba histolytica, and Blastocystis sp., among other protists, in all sludge samples examined. We also investigated the entry and exit of parasite DNA from the San Fernando wastewater treatment plant (WWTP). We observed a higher number of parasite DNA sequences in the plant's influent wastewater, but we also detected the discharge of DNA from pathogenic parasites in both effluent waters and biosolids.

Prevalence and distribution of subtypes of Blastocystis in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) farmed in Hainan, China

Blastocystis sp. is an important gastrointestinal parasite with global distribution, prevalent in humans, farmed animals, and wildlife. Therefore, this study aimed to investigate the prevalence and genetic diversity of Blastocystis sp. in Asiatic brush-tailed porcupines (Atherurus macrourus), bamboo rats (Rhizomys pruinosus), and masked palm civets (Paguma larvata) in Hainan Province, China. A total of 900 fecal samples were collected from three farmed animal species including 257 porcupines, 360 rats, and 283 civets. Genomic DNA was extracted from each fecal sample and Blastocystis sp. was detected by PCR at the small subunit ribosomal RNA (SSU rRNA) gene. A phylogenetic tree was constructed using the maximum likelihood method. Blastocystis sp. was detected in 47 (5.2%) fecal samples: 12 (4.7%) Asiatic brush-tailed porcupines, 8 (2.2%) bamboo rats, and 27 (9.5%) masked palm civets. Three known Blastocystis sp. subtypes, including ST1, ST4, ST5, and one unnamed subtype (unST), were found in one, 19, 26, and one animal, respectively. Subtypes ST4 and unST were detected in porcupines, ST4 in rats, and ST1 and ST5 in civets. Our results suggest that the three farmed animal species reported in this study could serve as reservoirs for potentially zoonotic Blastocystis sp. subtypes and transmit this parasite to humans, other farmed animals, and wildlife.

Metataxomics reveals Blastocystis subtypes mixed infections in Colombian children

Blastocystis sp., is an intestinal protist with a broad host range and a high prevalence in human populations worldwide, even in developed Western countries. The publication of conflicting evidence has divided the scientific community about the pathogenic role of this parasite. Even though, genetic studies on Blastocystis sp. revealed associations between genotypes and different pathogenic profiles. Conventionally, the detection of this parasite is based on microscopic or PCR methods, which offer meager or null performance in detecting mixed infections. In this work, we applied a metataxonomic NGS approach targeting the V4 region of the eukaryotic SSU-rRNA gene and classical phylogenetic methods. This approach allowed us to detect Blastocystis sp. in stool samples from infected children living in an urban setting in the city of Medellin attending the same daycare center. Phylogenetic analysis identified the subtypes present in the children as ST1, ST2, and ST3. Besides, mixed infections of subtypes ST1 + ST3 were spotted in 16% of the analyzed stool samples.

Distribution of Blastocystis subtypes isolated from various animal hosts in Thailand

Blastocystis is a parasitic protist of a variety of hosts, including humans. Mapping the distribution of Blastocystis and its genetic variants across different host species can help us understand the epidemiology of this organism and its role in health and disease. This study aimed to identify subtypes of Blastocystis detected in different animal hosts in Thailand. A total of 825 fecal samples belonging to 18 vertebrate orders, 36 families, 68 genera, and 80 species were collected. Of these, 111 specimens were Blastocystis-positive by culture. Seventy-nine samples were subjected to small subunit (SSU) ribosomal DNA amplification by PCR, and reliable subtype data were obtained for 61 specimens. At least 14 subtypes (ST), namely ST1 to ST10, ST14/ST24/ST25 complex, ST23, ST26, and ST29 were detected. In addition, Blastocystis was found in tortoises. ST1 (3.2%) and ST5 (11.5%) were found in pigs, ST2 (1.6%) and ST3 (3.2%) in non-human primates, ST4 (14.7%) in rodents and ruminants, ST6 (4.9%), ST7 (30%), ST9 (1.6%), and ST29 (1.6%) in birds, ST8 (6.6%) in Green peafowl and East Asian Porcupine, and ST10 (4.9%), ST14/ST24/ST25 (9.8%), ST23 (1.6%) and ST26 (1.6%) in ruminants. The sequence recovered from the elongated tortoises (Indotestudo elongata) (3.2%) was phylogenetically placed within the reptilian cluster of Blastocystis, for which no subtype system is available yet. Of note, we did not obtain Blastocystis sequences from any of the many canids and felids sampled in the study, and our data are in support of host specificity of Blastocystis, according to both colonization and subtype distribution.

Epidemiology of Blastocystis Infection: A Review of Data from Poland in Relation to Other Reports

Blastocystis is a common gut protist of humans and various animals worldwide, with a high level of genetic diversity. Neither its zoonotic potential and transmission routes nor its pathogenicity are fully known. This fact, and the fact that Blastocystis is the most abundant eukaryote in human faeces, raises the question of its relevance to public health. Here, we summarise (in relation to other reports) the results of studies on the prevalence and genotypic variation of Blastocystis, which were carried out in animals, humans, and in water environments in Poland. In humans, the prevalence ranged between 0.14 and 23.6%, in some animals reached 58.97%, and in water environments was 5.1%. Seven subtypes were identified in humans (ST1-ST4, ST6, ST7, and ST9), of which ST3 was the most common. Among animals (wild, livestock, and pet animals), eleven STs were identified, with differential host specificity. Humans and animals shared ST1, ST2, ST3, ST6, and ST7, while ST1 and ST3 were present in humans, animals, and water sources. These observations indicate the possibility of Blastocystis transmission between animals and humans. Further studies should be continued in search of the sources and transmission routes of Blastocystis in order to prevent the spread of infections among humans and animals.

Evolutionary analysis of cellular reduction and anaerobicity in the hyper-prevalent gut microbe Blastocystis

Blastocystis is the most prevalent microbial eukaryote in the human and animal gut, yet its role as commensal or parasite is still under debate. Blastocystis has clearly undergone evolutionary adaptation to the gut environment and possesses minimal cellular compartmentalization, reduced anaerobic mitochondria, no flagella, and no reported peroxisomes. To address this poorly understood evolutionary transition, we have taken a multi-disciplinary approach to characterize Proteromonas lacertae, the closest canonical stramenopile relative of Blastocystis. Genomic data reveal an abundance of unique genes in P. lacertae but also reductive evolution of the genomic complement in Blastocystis. Comparative genomic analysis sheds light on flagellar evolution, including 37 new candidate components implicated with mastigonemes, the stramenopile morphological hallmark. The P. lacertae membrane-trafficking system (MTS) complement is only slightly more canonical than that of Blastocystis, but notably, we identified that both organisms encode the complete enigmatic endocytic TSET complex, a first for the entire stramenopile lineage. Investigation also details the modulation of mitochondrial composition and metabolism in both P. lacertae and Blastocystis. Unexpectedly, we identify in P. lacertae the most reduced peroxisome-derived organelle reported to date, which leads us to speculate on a mechanism of constraint guiding the dynamics of peroxisome-mitochondrion reductive evolution on the path to anaerobiosis. Overall, these analyses provide a launching point to investigate organellar evolution and reveal in detail the evolutionary path that Blastocystis has taken from a canonical flagellated protist to the hyper-divergent and hyper-prevalent animal and human gut microbe.

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.

Prevalence and Subtype Distribution of Blastocystis in Tibetan Sheep in Qinghai Province, Northwestern China

Blastocystis is one of the most common intestinal protists in humans and a great number of animals, including sheep and goats. High prevalence and multiple subtypes of Blastocystis have been reported in sheep in several regions of China and elsewhere. However, there is a dearth of knowledge about Blastocystis in Tibetan sheep. A total of 761 fecal samples were collected from Tibetan sheep in seven counties of Qinghai Province, northwestern China, and were examined for the prevalence and subtypes of Blastocystis using molecular technology based on the partial small subunit ribosomal RNA gene of Blastocystis. The overall prevalence of Blastocystis in the investigated Tibetan sheep was 7.5% (57/761) using PCR and DNA Sanger sequencing, and differences in prevalence were observed among the ruminants from the seven counties (P < 0.01), and across four seasons (P < 0.01). Sequence analysis revealed five subtypes (ST14 (57.9%), ST10 (26.3%), ST12 (5.3%), ST21 (5.3%), and ST30 (5.3%)) of Blastocystis sp. in these Tibetan sheep, with ST14 as the predominant subtype. To our knowledge, this is the first report of Blastocystis colonization in Tibetan sheep.

Identification and genetic characterization of Blastocystis subtypes in Père David's deer (Elaphurus davidianus) from Shishou, China

Blastocystis is a protozoan parasite frequently reported in the gastrointestinal tract of humans and animals, with a global distribution. No information on the infections of Blastocystis in Père David's deer (Elaphurus davidianus, PDD) is available. In this study, a total of 128 fecal samples collected in the National Nature Reserve of Shishou, Hubei Province of China, were used to determine the occurrence and subtypes of Blastocystis in PDD. Amplification of the SSU rDNA gene confirmed the common presence of Blastocystis infection, with an observed prevalence of 56.3% (72/128). Through nucleotide sequencing and phylogenetic analysis, five known subtypes, which consisted of one zoonotic subtype (ST10) and four ruminant-specifical subtypes (ST21, ST23, ST25, and ST26), were identified in this study. This represents a high degree genetic diversity of parasites within the host. Of the 72 PCR-positive samples, ruminant-specific subtypes were the most frequently observed, with ST21 being the most prevalent subtype (56.9.7%, 41/72). This is the first report characterizing the molecular subtypes of Blastocystis in PDD. The findings demonstrate a broad diversity and zoonotic potential of Blastocystis in PDD. Further study of the transmission potential between wildlife and humans or domestic animals in the region is required.

Prevalence of Blastocystis sp. in freshwater fishes, poultry, and caprine from Penang, Malaysia

Blastocystis is an enigmatic intestinal protist of humans and many animals. There is growing interest in its potential as an enteric pathogen, and the possible role of domestic and in-contact animals as reservoirs for human infection. The purpose of this study was to determine the prevalence of Blastocystis infection in fishes, poultry, and caprine in Penang, Malaysia. A total of 353 faecal samples/intestinal contents, consisting of 123 intestinal contents from freshwater fishes, 96 intestinal contents of commercially barn-reared chickens, 84 intestinal contents of barn-reared quails, and 50 faecal samples of caprine (29 from meat goats and 21 from dairy goats) were collected. Faecal sample/intestinal content from each animal was subjected to in-vitro cultivation method using Jones' medium supplemented with 10% horse serum. The respective colonization frequencies for dairy and meat goats were 47.6% and 31.0%, whereas 26.1% was recorded for chickens and 16.7% for quails. None of the freshwater fishes were found infected with Blastocystis. The organism was most commonly seen as spherically shaped vacuolated forms and cell diameter was significantly larger in poultry than in caprine. For further studies, molecular characterization of Blastocystis in poultry and livestock animals in the study area is highly recommended.

Rare Occurrence of Blastocystis in Pet Animals and Their Owners in the Pomeranian Voivodeship in Poland in the Light of Literature Data

Blastocystis is an intestinal microeukaryote with ambiguous pathogenicity, commonly detected in human feces worldwide. It comprises at least 28 genetically diverse subtypes (STs), 12 of which also occur in a wide range of animal species, giving rise to suspicion of zoonotic transmission. To investigate this, we conducted a molecular study of 145 stool samples of pet animals, and 67 of their owners, living in an urban area in Poland. Blastocystis was detected in only three (2.1%) animal samples (of two bearded agamas and a leopard gecko), while all dogs, cats, and pet rodents were Blastocystis-negative. Blastocystis was also present in three (4.5%) owners of animals, but they were cat owners, not reptile owners, and the subtypes identified in them differed significantly from those of reptiles. Additionally, the frequency of Blastocystis in different groups of dogs (depending on how they were kept) was analyzed. This work is the first to find Blastocystis in pet reptiles, and we encourage further investigation of Blastocystis in this poorly examined group of animals, as well as continued study on the transmission of this microorganism between humans and animals.

Genetic diversity of Blastocystis subtypes in the Alpine musk deer (Moschus chrysogaster) in Gansu province, northwestern China

Blastocystis sp. is a gastrointestinal pathogen that is frequently found in humans and animals worldwide. In this study, 201 fecal samples were collected from captive Alpine musk deer (Moschus chrysogaster) at three farms in Gansu province. Blastocystis was detected and subtyped by amplifying and sequencing the small subunit ribosomal DNA gene. The overall prevalence of Blastocystis was 39.8% (80/201). Five known Blastocystis subtypes (STs), including ST1 (n = 1), ST4 (n = 12), ST10 (n = 50), ST14 (n = 6), and ST24 (n = 11), were identified using subtyping and evolutionary analysis. ST10 was the most common ST observed in each farm. This study showed the infection status and genetic characteristics of Blastocystis in M. chrysogaster. Based on the surveyed data, because various potentially zoonotic STs, such as ST1, ST4, ST10, ST14, and ST24, were detected, it is believed that the zoonotic risk of Blastocystis from the Alpine musk deer in this area cannot be ignored.

Prevalence and genotypes/subtypes of Enterocytozoon bieneusi and Blastocystis sp. in different breeds of cattle in Jiangxi Province, southeastern China

Enterocytozoon bieneusi and Blastocystis sp. are common zoonotic pathogens that parasitize in the small intestine of humans and animals, posing a threat to public health. However, little information is available on the prevalence and genotypes/subtypes of E. bieneusi and Blastocystis sp. in cattle in Jiangxi Province, southeastern China. In the present study, 556 fecal samples of cattle were collected from Nanchang city, Gao'an city, Xinyu city, and Ji'an city in Jiangxi Province. All samples were examined for the presence of E. bieneusi by nested PCR analysis of the ribosomal internal transcribed spacer (ITS) and Blastocystis sp. using PCR targeting the SSU rRNA gene. The overall prevalence of E. bieneusi and Blastocystis sp. was 5.4% (30/556) and 54.9% (305/556), respectively. The prevalence of E. bieneusi in dairy cattle, beef cattle, and buffaloes was 7.9% (13/165), 3.9% (11/283), and 5.6% (6/108), respectively. Eleven E. bieneusi genotypes were identified in this study, including six known genotypes, D (n = 10), I (n = 5), J (n = 4), IV (n = 4), N (n = 1), and BEB4 (n = 1), and five novel genotypes, JX-I to JX-V (n = 1), with genotype D as the predominant genotype in cattle. Phylogenetic analysis showed that six genotypes of E. bieneusi, D, IV, and JX-II to JX-V, were clustered into zoonotic group 1, whereas the remaining five genotypes belonged to group 2. Moreover, seven, seven, four, and five types were identified by multilocus sequence typing (MLST) at the MS1, MS3, MS4, and MS7 loci, respectively, forming three distinct multilocus genotypes (MLGs). In addition, the prevalence of Blastocystis sp. was 42.4% (70/165), 59.4% (168/283), and 62.0% (67/108) in dairy cattle, beef cattle, and buffaloes, respectively. Sequence analysis revealed that ST1, ST5, ST10, and ST14 of Blastocystis sp. were identified in these cattle, with ST10 being the major subtype. ST1 and ST5 are potential zoonotic subtypes. These findings have important implications for the control of E. bieneusi and Blastocystis sp. in cattle in Jiangxi Province.

Collateral Damage in the Human Gut Microbiome - Blastocystis Is Significantly Less Prevalent in an Antibiotic-Treated Adult Population Compared to Non-Antibiotic Treated Controls

Antibiotics can drive the rapid loss of non-target, phylogenetically diverse microorganisms that inhabit the human gut. This so-called “collateral damage” has myriad consequences for host health and antibiotic mediated changes to the gut microbiota have been implicated in the aetiology of many chronic diseases. To date, studies have largely focused on how antibiotics affect the bacterial fraction of the gut microbiome and their impact on non-bacterial members, including prevalent eukaryal species, such as Blastocystis, remains largely unknown. Here we assessed the prevalence and diversity of Blastocystis in an elderly adult group that were in receipt of antibiotics (n = 86) and an equivalent non-antibiotic treated group (n = 88) using a PCR-based approach. This analysis revealed that although similar subtypes were present in both groups, Blastocystis was significantly less prevalent in the antibiotic-treated group (16%) compared to non-antibiotic treated controls (55%); Fisher’s Exact test, p < 0.0001). Given that antibiotics target structures and molecules of prokaryotic cells to kill or inhibit bacterial populations, the most likely explanation for differences in prevalence between both groups is due to secondary extinctions owing to the potential dependence of Blastocystis on bacteria present in the gut microbiome that were negatively affected by antibiotic treatment. Although further work is required to explore this hypothesis in greater detail, these data clearly show that Blastocystis prevalence in human populations is negatively associated with antibiotic treatment. This finding may be relevant to explaining patterns of variation for this microorganism in different human populations and cohorts of interest.

Occurrence and subtyping of Blastocystis in coypus (Myocastor coypus) in China

BACKGROUND

Blastocystis is an anaerobic unicellular protist frequently detected in the gastrointestinal tracts of humans and animals worldwide. However, the prevalence and subtype distribution of Blastocystis in the coypu (Myocastor coypus) population have not been reported so far. The aim of this study was to determine the prevalence, genetic characteristics, and zoonotic potential of Blastocystis isolates detected in coypus in China.

RESULTS

A total of 308 fecal samples were collected from coypus in seven regions across China and subsequently examined. Blastocystis was detected in 44 (14.3%) specimens by nested PCR amplification of the small subunit ribosomal rRNA (SSU rRNA) gene. Further DNA sequencing and phylogenetic analyses resulted in the identification of two zoonotic known subtypes, ST4 and ST5, and an unknown subtype. ST4 was the most predominant subtype observed in the samples. ST5 infections were only observed in three coypus. Factors that were associated with prevalence of Blastocystis included age, geographical region and subtype. Interestingly, this is the first report about a potentially novel subtype infecting coypus.

CONCLUSIONS

This is the first comprehensive report of Blastocystis in M. coypus across a wide geographic range of China. A moderate degree of genetic divergence was observed. The presence of zoonotic subtypes in farmed M. coypus suggests that these animals have the potential to transmit blastocystosis to both humans and domestic animals. These findings provide a better understanding of the genetic diversity of Blastocystis in rodents and contribute towards the establishment of efficient blastocystosis control strategies in the investigated areas.

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.

Prevalence and Molecular Characterization of the Zoonotic Enteric Protozoans Cryptosporidium spp., Enterocytozoon bieneusi, and Blastocystis from Pallas's Squirrels (Callosciurus erythraeus) in Kanagawa Prefecture, Japan

Pallas's squirrel (Callosciurus erythraeus) was introduced in Japan in the 1930s and has since established itself in several areas across the country. Although wild Sciuridae populations have been demonstrated to be potential reservoirs for zoonotic enteric protozoa, epidemiological studies of such pathogens in Japan are scarce. Here, we examined 423 fecal samples from Pallas's squirrels captured in Kanagawa Prefecture, Japan, using PCR and DNA sequencing to determine the occurrence of Cryptosporidium spp., Enterocytozoon bieneusi, and Blastocystis. The overall prevalence of Cryptosporidium spp., E. bieneusi, and Blastocystis was 4.3% (18/423 samples), 13.0% (55/423 samples), and 44.0% (186/423 samples), respectively. The prevalence of Blastocystis and E. bieneusi was significantly higher in spring (60.1% and 17.4%, respectively) than in winter (27.6% and 8.6%, respectively [P < 0.01]). Sequence analysis of Cryptosporidium spp., targeting the partial small subunit ribosomal RNA gene (SSU rDNA), showed 100% identity (541/541 bp) to Cryptosporidium ubiquitum, and analysis of the gp60 gene showed 99.76% (833/835 bp) identity to C. ubiquitum subtype XIIh. The sequences of the ribosomal internal transcribed spacer region of E. bieneusi and the partial SSU rDNA of Blastocystis were identified as E. bieneusi genotype SCC-2 and Blastocystis subtype 4, respectively. This study confirmed the presence of C. ubiquitum, E. bieneusi, and Blastocystis in Pallas's squirrels in Kanagawa Prefecture. Because Pallas's squirrels inhabit urban areas, living close to humans, the species may serve as a potential source of infection in human populations. IMPORTANCE Pallas's squirrel is designated a "regulated organism" under the Invasive Alien Species Act in Japan, and municipal authorities are introducing control measures to reduce its populations. It has been suggested that wild mammals may play a role in contaminating the environment with zoonotic pathogens. The present study detected the enteric pathogens Cryptosporidium ubiquitum, Enterocytozoon bieneusi, and Blastocystis in the feces of Pallas's squirrels inhabiting Kanagawa Prefecture, Japan. These pathogens persist in the environment and contaminate soils and water, which may potentially infect humans. Because Pallas's squirrels in Kanagawa Prefecture are found in urban areas, where they are in close contact with human populations, continued monitoring of zoonotic diseases among squirrel populations will be important for evaluating the significance of wildlife in pathogen transmission.

Genetic characterization and zoonotic potential of Blastocystis from wild animals in Sichuan Wolong National Natural Reserve, Southwest China

Blastocystis is a prevalent eukaryotic parasite that has been identified in a wide range of hosts. Several species are considered potential sources of Blastocystis infection in humans, but little is known about the prevalence of Blastocystis in wild animals. In this study, the prevalence and subtypes of Blastocystis were investigated to assess the zoonotic potential of wild animals in Sichuan Wolong National Natural Reserve. A total of 300 fecal samples were collected from 27 wildlife species in three areas of the Reserve. The subtype (ST), genetic characteristics, and prevalence of Blastocystis were determined by PCR amplification of part (~600 bp) of the SSU rRNA gene. Thirty fecal samples (10.0%) were Blastocystis-positive. The highest prevalence of Blastocystis was found in Yinchanggou (18.3%), with significantly less found in Niutoushan (7.5%) and Genda (5.5%) (p < 0.05). No significant differences were associated with different orders of animals in prevalence, which may be because of the small number of positive samples obtained. Sequence analysis showed five subtypes (ST1, ST3, ST5, ST13, and ST14), with ST13 and ST14 being predominant (33% each), followed by ST1 (20%). This is the first molecular investigation of Blastocystis infection in the wild animals of southwestern China. Subtypes ST1, ST3, ST5, and ST14 have previously been identified in humans, suggesting that wild animals may be potential reservoirs of Blastocystis for humans.

Molecular prevalence and subtype distribution of Blastocystis sp. in Asia and in Australia

Blastocystis is a prevalent protozoan parasite reported in humans, animals, and environmental samples. Over the past decade, numerous studies have investigated the prevalence and subtype distribution of Blastocystis sp. alongside with its genetic and biochemical features. However, studies on subtype distribution of this protozoan in humans, animals, and environmental samples represent the potential transmission routes. In this review, we evaluated studies performed in Asian countries and in Australia to provide an overview of environmental factors on the prevalence and subtype distribution of Blastocystis sp. among humans, animals, and the environment.

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.

Blastocystis occurrence and subtype diversity in wild European terrestrial mammals - The case of Białowieża Primeval Forest (NE Poland)

Blastocystis cf. Blastocystis hominis is the most common unicellular parasite found in human and animal intestines. Little is known about the life cycle, transmission and mechanisms of pathogenesis for this parasite. The aim of this study was to obtain new data on the genetic diversity of Blastocystis in selected species of mammals found in the Białowieża Primeval Forest (BPF), Poland, the best preserved lowland forest in temperate Europe. 113 faecal samples were collected in the period 2018–2020 from seven species of wild mammals occurring within the Polish part of BPF and its surroundings. Blastocystis was detected by molecular amplification and sequencing the small subunit rRNA gene. The overall prevalence of Blastocystis in animals was 8.9%. A larger number of stool samples (90) were collected from European bison and only for this species was it possible to calculate the prevalence of infection (5.6%). The isolates obtained from European bison were classified as ST1, ST3, ST5, ST7. Blastocystis was also detected in the grey wolf (Canis lupus) (ST5), wild boar (Sus scrofa) (ST5) and red deer (Cervus elaphus) (ST1). In conclusion, for the first time we have demonstrated the presence of Blastocystis in wild European bison. Preliminary studies have shown that Blastocystis is present in at least 4 species of wild mammals in the BPF area and that it exhibits great genetic diversity.

Blastocystis is present in wild mammals in the Białowieża Primeval Forest

Blastocystis in the Białowieża Primeval Forest exhibits great genetic diversity

Intra-species and interspecific transmission of Blastocystis in Białowieża Primeval Forest is highly probable.

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.

Detection and molecular identification of Blastocystis isolates from humans and cattle in northern Egypt

Blastocystis is one of the less well-understood waterborne protozoa of medical and veterinary importance. The present study aimed to detect, identify, and subtype Blastocystis in cattle and humans in northern Egypt and to investigate the potential for zoonotic transmission. Fecal samples were collected from 136 humans (68 in contact with animals and 68 no animal contact) and 190 cattle from a rural area in Kafr El-Sheikh Province, Egypt. All samples were microscopically examined by direct wet mount technique and cultured in Jones' medium. Genomic DNA was extracted from positive cultures. A region of the Blastocystis small subunit ribosomal ribonucleic acid (SSU rRNA) gene was amplified using PCR. Blastocystis subtypes were identified by sequencing of the amplified SSU rRNA gene. The relatedness of sequence types obtained in this study and others submitted in GenBank was compared according to their genetic relatedness. Out of 136 human and 190 cattle samples, Blastocystis was detected in 53 (38.9%) and 37 (19.4%), respectively using either culture or direct wet mount. Blastocystis SSU rRNA gene was amplified in 55 samples (32 humans and 23 animals). Six subtypes were identified (STs 1-3 in humans and ST4, ST10 and ST14 in cattle) and were distinguishable with inter (up to 0.075) and intra (up to 0.024) subtype variations. A close phylogenetic relationship between human and animal isolated STs 1-4 was demonstrated. To the best of our knowledge, this is the first study to investigate the the potentiality for zoonotic transmission of certain Blastocystis subtypes in northern Egypt.

PREVALENCE AND MOLECULAR CHARACTERISTICS OF BLASTOCYSTIS SP. FROM PEAFOWL (PAVO CRISTATUS) IN CHINA

This study is the first description of Blastocystis infection in peafowls in China. In total, 143 fecal specimens collected from a peafowl breeding farm in Henan Province were tested for Blastocystis infection by PCR assay targeting the small subunit ribosomal RNA (SSU rRNA) gene, and a total of 50 specimens (35.0%) were positive. Based on sequences and phylogenetic analysis, 2 genetically distinct subtypes (STs) were determined: ST9 and ST7. ST9 was the predominant subtype, accounting for 82% (41/50). The rare zoonotic subtype ST7 was also identified in peafowls, with the infection rate of 18% (9/50). Altogether, the present study is the first report of the prevalence and molecular characteristics of Blastocystis in peafowls in central China. The presence of zoonotic subtypes in peafowls suggests the potential risk of zoonotic transmission of Blastocystis to workers at peafowl farms.

Wide Genetic Diversity of Blastocystis in White-Tailed Deer (Odocoileus virginianus) from Maryland, USA

Blastocystis is a gastrointestinal protist frequently reported in humans and animals worldwide. Wildlife populations, including deer, may serve as reservoirs of parasitic diseases for both humans and domestic animals, either through direct contact or through contamination of food or water resources. However, no studies of the occurrence and subtype distribution of Blastocystis in wildlife populations have been conducted in the United States. PCR and next generation amplicon sequencing were used to determine the occurrence and subtypes of Blastocystis in white-tailed deer (Odocoileus virginianus). Blastocystis was common, with 88.8% (71/80) of samples found to be positive. Twelve subtypes were identified, ten previously reported (ST1, ST3, ST4, ST10, ST14, ST21, and ST23–ST26) and two novel subtypes (ST30 and ST31). To confirm the validity of ST30 and ST31, MinION sequencing was used to obtain full-length SSU rRNA gene sequences, and phylogenetic and pairwise distance analyses were performed. ST10, ST14, and ST24 were the most commonly observed subtypes. Potentially zoonotic subtypes ST1, ST3, or ST4 were present in 8.5% of Blastocystis-positives. Mixed subtype infections were common (90.1% of Blastocystis-positives). This study is the first to subtype Blastocystis in white-tailed deer. White-tailed deer were found to be commonly infected/colonized with a wide diversity of subtypes, including two novel subtypes, zoonotic subtypes, and subtypes frequently reported in domestic animals. More studies in wildlife are needed to better understand their role in the transmission of Blastocystis.

Frequency of enteroparasites in Cebidae and Callitrichidae primates at the Zoológico de Cali, Colombia: zoonotic implications

Introduction: Enteroparasites can cause problems in animals kept under human care in zoos and shelters. Wild animals have low parasitic loads but when sheltered in closed places they can be higher and lead to clinical manifestations, which increases the cost of medical treatments and care. On the other hand, some enteroparasites can represent a potential risk of zoonotic infection for their animal keepers, visitors, and other zoo animals. In addition, they could affect recovery programs for endangered species. Objectives: To establish the presence and prevalence of potentially zoonotic enteroparasites in primates of the Cebidae and Callitrichidae families at the Zoológico de Cali from September to November, 2017. Materials and methods: We conducted a prospective cross-sectional study. Serial samples from 50 individuals belonging to seven species and two primate families were analyzed by ova and parasite test, flotation, and Kinyoun stain between September and November, 2017. Results: In order of frequency, the parasite genera found in the seven primate species evaluated were Blastocystis spp., Trichomonas spp., Giardia spp., Entamoeba spp., Strongyloides spp., Cyclospora sp., and Trichuris sp. Conclusions: At least six of the parasite genera found have potential zoonotic implications. It is necessary to establish what are the infection sources at the Zoológico de Cali and implement management protocols to reduce the risk of transmission to both humans and other animals in the collection. Additionally, we offer relevant information on the zoonotic potential of each of the enteroparasites found.

Parasites, Drugs and Captivity: Blastocystis-Microbiome Associations in Captive Water Voles

(1) Background: Blastocystis is a microbial eukaryote inhabiting the gastrointestinal tract of a broad range of animals including humans. Several studies have shown that the organism is associated with specific microbial profiles and bacterial taxa that have been deemed beneficial to intestinal and overall health. Nonetheless, these studies are focused almost exclusively on humans, while there is no similar information on other animals. (2) Methods: Using a combination of conventional PCR, cloning and sequencing, we investigated presence of Blastocystis along with Giardia and Cryptosporidium in 16 captive water voles sampled twice from a wildlife park. We also characterised their bacterial gut communities. (3) Results: Overall, alpha and beta diversities between water voles with and without Blastocystis did not differ significantly. Differences were noted only on individual taxa with Treponema and Kineothrix being significantly reduced in Blastocystis positive water voles. Grouping according to antiprotozoal treatment and presence of other protists did not reveal any differences in the bacterial community composition either. (4) Conclusion: Unlike human investigations, Blastocystis does not seem to be associated with specific gut microbial profiles in water voles.

First identification and molecular subtyping of Blastocystis sp. in zoo animals in southwestern China

BACKGROUND

Blastocystis sp. is an anaerobic protozoan that parasitizes many animal hosts and the human gastrointestinal tract, and its pathogenicity is controversial. Captive wildlife may be potential reservoirs for human infection with Blastocystis sp. The present study was performed to investigate the prevalence and subtype distribution of Blastocystis sp. in zoo animals in Sichuan Province, southwestern China.

METHODS

A total of 420 fresh fecal samples were collected from 54 captive wildlife species in four zoos in southwestern China between June 2017 and September 2019. The prevalence and subtype (ST) genetic characteristics of Blastocystis sp. were determined by PCR amplification of the barcode region of the SSU rRNA gene and phylogenetic analysis.

RESULTS

Overall, 15.7% (66/420) of the animal samples and 20.7% (14/54) of the species tested were shown to be infected with Blastocystis sp. The highest prevalence of Blastocystis sp. was found in Panzhihua Zoo (24.3%), which was significantly higher than that in Chengdu Zoo (6.9%), and Xichang Zoo (2.9%) (P < 0.05). There are also significant differences in the prevalence of Blastocystis sp. among different species (P < 0.05), and the highest of Blastocystis sp. prevalence was observed in white-cheeked gibbon, black great squirrel, and red giant flying squirrel (100%). Subtype analysis of Blastocystis sp. revealed nine subtypes, including six zoonotic STs (ST1-5, and ST8) and three animal-specific STs (ST10, ST14, and ST17), with ST17 as the predominant subtype (26/66) in Blastocystis sp.-positive isolates.

CONCLUSIONS

To our knowledge, this is the first report on the prevalence and subtype distribution of Blastocystis sp. among captive wildlife in zoos in southwestern China. This study highlights that these animals may serve as reservoirs for human Blastocystis sp. infections.

Genetic Diversity and Zoonotic Potential of Blastocystis in Korean Water Deer, Hydropotes inermis argyropus

Blastocystis is a protozoan parasite commonly detected in the intestinal tract of humans and animals. It has been actively studied worldwide; however, information on Blastocystis is limited in Korea. Because there is an increasing concern about the contact between wildlife and domestic animals or humans, we assessed the infection status and zoonotic potential of Blastocystis in Korean water deer (KWD, Hydropotes inermis argyropus) using genotyping and phylogenetic analysis. A total of 125 fresh fecal samples were collected from KWD which were killed by vehicles on highways or roadsides in this study. Among the 125 samples, 51 (40.8%) were PCR positive. We performed nucleotide sequencing and phylogenetic analysis of 26 of the 51 PCR-positive samples. By analyzing Blastocystis 18S rRNA, two subtypes (ST4 and ST14) were identified in this study. Of the 26 samples analyzed, 25 were identified as ST14 and one as ST4. Infection of ST14 in humans has not been reported. Although only one ST4 sample was detected in this study, ST4 has zoonotic potential without showing ruminant specificity. Thus, continuous attention should be provided to the potential of transmission between wildlife and domestic animals and humans.

Blastocystis in domesticated and wild mammals and birds

Blastocystis is a ubiquitous parasite that infects a broad range of vertebrate hosts including humans and domestic and wild animals. While human infections have been occasionally associated with gastrointestinal illnesses and/or urticaria, animal infections are not usually associated with disease. However, from a public health perspective, most subtypes isolated in humans have also been isolated from animals raising the question of the importance of animal reservoirs in the epidemiology of this parasite. The identification of Blastocystis in water supplies suggests water can be a potential vehicle in the transmission of this parasite not only for humans but also for animals. In addition, Blastocystis has been detected in retail fresh produce. Knowledge of this parasite has greatly expanded in the last two decades from simple microscopic observations to the application of molecular tools to explore Blastocystis taxonomy and epidemiology. This review provides a comprehensive overview of Blastocystis in animals highlighting the subtype diversity of this widespread and genetically diverse parasite in different animal groups. This information will be useful in understanding the current status of taxonomy, epidemiology, zoonotic potential, and public health importance of Blastocystis.

First molecular subtyping and phylogeny of Blastocystis sp. isolated from domestic and synanthropic animals (dogs, cats and brown rats) in southern Iran

BACKGROUND

Blastocystis sp. is a common intestinal protist that infects humans and many animals globally. Thus far, 22 subtypes (STs) have been identified in mammalian and avian hosts. Since various STs are common to humans and animals, it was suggested that some human infections might arise from zoonotic transmission. Therefore, the aim of this study was to assess the presence of Blastocystis sp. in domestic (dogs and cats) and synanthropic animals (rats) of Fars Province, Iran, and to genetically characterize the samples.

METHODS

A total of 400 fresh faecal samples from 154 dogs, 119 cats, and 127 rats were inspected by direct microscopy, Wheatley's trichrome staining, in vitro culture, and 18S rRNA gene nested-PCR. Finally, sequencing and phylogenetic analyses were performed.

RESULTS

Out of 400 samples, 47 (11.8%) and 61 (15.3%) samples were detected as positive by direct wet mount and culture, respectively. Molecular analysis detected a larger number of positive samples (n = 70, 17.5%): nested-PCR showed that 29 (18.8%) dogs, 21 (17.7%) cats, and 20 (15.8%) rats were infected by Blastocystis sp. Sequence analysis of positive samples indicated the presence of zoonotic STs in all investigated host species. Specifically, ST2 (allele 9), ST3 (allele 34), ST4 (allele 94), ST7 (allele 99), ST8 (allele 21), and ST10 (allele 152) were detected in dogs; ST1 (allele 2), ST3 (allele 34), ST4 (allele 94), ST10 (allele 152), and ST14 (allele 159) were detected in cats; and ST1 (allele 2), ST3 (allele 34), and ST4 (allele 92) were detected in rats.

CONCLUSIONS

Our data suggest that domestic dogs and cats can serve as possible reservoirs for in-contact humans, especially those who handle shelter-resident and client-owned animals. Moreover, rats as synanthropic animals can function as a potential source of human infections. Conversely, humans can act as a source of infections to animals. These results should be reinforced in future molecular epidemiological studies.

First Report on the Occurrence and Subtypes of Blastocystis in Pigs in Poland Using Sequence-Tagged-Site PCR and Barcode Region Sequencing

Blastocystis is an enteric microorganism commonly found in humans and animals worldwide. Its pathogenic role in humans and transmission patterns has not been fully explained. However, nine subtypes (ST1-8, ST12) are considered as potentially zoonotic. Studies from various regions of the world show that pigs are mainly infected with ST5. Although pigs are important farmed animals in Poland, the question of Blastocystis infection in these animals has not yet been investigated. Herein, 149 pig stool samples from 10 Polish pig farms were analyzed using sequence-tagged-site PCR and barcode region sequencing. The percentage of samples in which Blastocystis was identified using each method separately was similar: 38.25% and 37.58%, respectively. However, the percentage of positive results obtained by combining both methods was 46.97%, which means that, depending on the method used, the number of undetected samples varied between 8.72% and 9.39%. This shows the methodological limitations of up-to-date molecular approaches commonly used in Blastocystis research. A moderate infection rate (44.4-50%) observed in different pig age groups with a vital predominance of ST5 (94.28%) in every age group shows that pigs are a likely natural host of ST5. A small percentage of mixed infections, namely ST5/ST1 (5.26%), ST5/ST3 (1.75%), and ST3/ST1 (1.75%), was observed only in animals of older age, suggesting that ST3 and ST1 can be acquired by pigs during contact with humans. This study provides the first data on the prevalence and Blastocystis subtypes (STs) distribution in pigs in Poland. The results also highlight the need for the development of new methods capable of detecting highly genetically diverse Blastocystis isolates and mixed infections.

First Report on the Prevalence and Subtype Distribution of Blastocystis sp. in Edible Marine Fish and Marine Mammals: A Large Scale-Study Conducted in Atlantic Northeast and on the Coasts of Northern France

Blastocystis is frequently identified in humans and animal hosts and exhibits a large genetic diversity with the identification of 17 subtypes (STs). Despite its zoonotic potential, its prevalence and ST distribution in edible marine fish and marine mammals remain unknown. A large-scale survey was thus conducted by screening 345 fish caught in Atlantic Northeast and 29 marine mammals stranded on the coasts of northern France for the presence of the parasite using real-time Polymerase Chain Reaction PCR. The prevalence of the parasite was about 3.5% in marine fish. These animals were mostly colonized by poikilotherm-derived isolates not identified in humans and corresponding to potential new STs, indicating that fish are natural hosts of Blastocystis. Marine fishes are also carriers of human STs and represent a likely limited source of zoonotic transmission. 13.8% of the marine mammals tested were colonized and 6 different STs were identified including 3 potential new STs. The risk of zoonotic transmission through marine mammals is insignificant due to the lack of repeated contact with humans. The present survey represents the first data regarding the prevalence and ST distribution of Blastocystis in marine fish and marine mammals and provides new insights into its genetic diversity, host range and transmission.

Exploring Micro-Eukaryotic Diversity in the Gut: Co-occurrence of Blastocystis Subtypes and Other Protists in Zoo Animals

Blastocystis is a genetically diverse microbial eukaryote thriving in the gut of humans and other animals. While Blastocystis has been linked with gastrointestinal disorders, its pathogenicity remains controversial. Previous reports have suggested that one out of six humans could be carrying Blastocystis in their gut, while the numbers could be even higher in animals. Most studies on Blastocystis are either exclusively targeting the organism itself and/or the associated prokaryotic microbiome, while co-occurrence of other microbial eukaryotes has been mainly ignored. Herein, we aimed to explore presence and genetic diversity of Blastocystis along with the commonly occurring eukaryotes Cryptosporidium, Eimeria, Entamoeba and Giardia in the gut of asymptomatic animals from two conservation parks in the United Kingdom. Building upon a previous study, a total of 231 fecal samples were collected from 38 vertebrates, which included 12 carnivorous and 26 non-carnivorous species. None of the animals examined herein showed gastrointestinal symptoms. The barcoding region of the small subunit ribosomal RNA was used for subtyping of Blastocystis. Overall, 47% of animal species were positive for Blastocystis. Twenty six percent of samples carried more than one subtypes, including the newly identified hosts Scottish wildcat, bongo and lynx. Fifty three percent of samples carried at least another microbial eukaryote. Herewith, we discuss potential implications of these findings and the increasingly blurred definition of microbial parasites.

Blastocystis spp. subtype 10 infected beef cattle in Kamal and Socah, Bangkalan, Madura, Indonesia

Background and Aim:

Blastocystis spp. is a gastrointestinal parasite that can infect both humans and animals and has the potential to become a zoonotic parasite. This study analyzed a subtype (ST) of Blastocystis spp. that had infected beef cattle in Kamal and Socah, Bangkalan, Madura, Indonesia.

Materials and Methods:

Fresh stool samples were collected from 108 beef cattle at Kamal and Socah, Bangkalan, Madura, Indonesia. Blastocystis spp. were detected both morphologically and genetically based on the 18S rRNA gene. The morphology of Blastocystis spp. from the stool samples and cultured samples were observed under a light microscope. Blastocystis spp. from 20 positive cultures were amplified through polymerase chain reaction, and the resultant sequences were identified by ST.

Results:

One hundred and eight (100%) fecal samples from the fresh or cultured stools were positive morphologically for Blastocystis spp. Molecularly, all 20 of the samples selected for DNA analysis were found to be Blastocystis spp. ST 10.

Conclusion:

Based on morphological and molecular detection, the prevalence of Blastocystis spp. infection in beef cattle within Kamal and Socah, Bangkalan, Madura, Indonesia, was high. About 100% were non-zoonotic parasites. This was the first report of Blastocystis spp. ST 10 found in infected beef cattle in Kamal and Socah, Bangkalan, Madura, Indonesia.

Molecular Detection and Subtyping of Blastocystis Detected in Wild Boars (Sus scrofa) in South Korea

Blastocystis is a genus of parasitic protozoans that live in humans, mammals, and birds and which has been widely studied due to its low host specificity. Limited data are available, however, regarding its presence in wildlife, particularly in South Korea. Contact between wild boars (Sus scrofa) and livestock or humans has steadily increased as wild boars venture down from the mountains to farms and residential areas. In this study, we examined the status and subtypes (STs) of Blastocystis in wild boars in South Korea and confirmed its zoonotic potential. From March 2016 to November 2018, we collected 433 fecal samples throughout the country from trapped or road-killed wild boars. The 18S rRNA gene was used for molecular identification and subtyping and the proportion of PCR-positive samples was 10.4%. We then assessed positive samples for associations with sex, region, and seasonal infection; however, no statistical significance was observed for any variable other than season. Phylogenetic analyses revealed that all sequences belonged to subtype 5 and had 99.5-99.9% identity with sequences obtained from Japanese cattle (Bos taurus) and 97.1% identity with sequences obtained from Chinese. Subtype 5 has been implicated in zoonoses, indicating that Korean wild boars could transmit Blastocystis to humans and other livestock. Our results, in accordance with the One Health concept, strongly support continued interest and efforts by public health and disease control organizations toward transmission prevention.

Assessment of the subtypes and the zoonotic risk of Blastocystis sp. of experimental macaques in Yunnan province, southwestern China

Blastocystis is an enteral eukaryote with an omnipresent existence in animals and humans globally. Animals have been proposed to be a major reservoir for the transmission of Blastocystis to individuals due to their high prevalence and large amount of zoonotic subtypes. However, limited data on Blastocystis infection in experimental macaques in China exists. The objective of the current study was to investigate the frequency and subtypes of Blastocystis infection in macaques in southwestern China. A total of 505 fecal samples were collected from experimental macaques in Yunnan province and were analyzed by nested PCR and phylogenetic analyses on the basis of small subunit rRNA (SSU rRNA) gene fragments. A total of 235 specimens were positive for Blastocystis sp., and the prevalence of Blastocystis sp. was 46.5% (235/505). Significant differences in prevalence were also observed among the various species of macaques (P < 0.0133, df = 2, χ² = 8.64) and the different feed types (P < 0.0093, df = 1, χ² = 6.77). Moreover, three zoonotic subtypes, ST1, ST3, and ST5, were identified by DNA sequence analysis. There were mainly single subtype infections with some mixed subtype infections, and the predominant subtype was ST3. The results suggested a high prevalence and diversified subtypes in macaques in Yunnan province, southwestern China. Macaques are likely to be potential reservoirs capable of zoonotic transmission of Blastocystis sp. to humans. To our knowledge, this study is the first large-scale systematic analysis of Blastocystis sp. colonization in Yunnan province in the subtropics of China; these results contribute to the in-depth study of genetic characteristics and the prevention, control, and treatment of Blastocystis sp. in macaques in Yunnan province and other regions.

Molecular characterization of Blastocystis sp. in captive wildlife in Bangladesh National Zoo: Non-human primates with high prevalence and zoonotic significance

Blastocystis sp. is a protozoan parasite, commonly found in the gastrointestinal tracts of animals and humans globally. The parasitic species has wide genetic diversity. Currently the mammalian and avian isolates of the parasite are grouped into 17 well known subtypes (STs), of which ten (ST1-ST9, ST12) are reported in humans. To assess the genetic diversity of Blastocystis sp. in wildlife, a total of 200 fresh fecal samples were collected from 32 mammalian wildlife species in Bangladesh National Zoo. Blastocystis sp. was screened and subtyped by PCR amplification and sequencing of the small subunit ribosomal RNA (SSU rRNA) gene. The minimum prevalence of Blastocystis sp. infection was 15.5% (31/200) in zoo animals. Eight out of 32 wildlife animal species (25.0%) were infected with Blastocystis sp. Among them, the occurrence of Blastocystis sp. was higher in non-human primates (NHPs) (31.8%) than that in herbivores (4.9%) and carnivores (0). Nucleotide sequence analysis of the SSU rRNA gene revealed seven different Blastocystis sp. subtypes, such as ST1, ST2, ST3, ST10, ST11, ST13 and ST14 in the wild animals. ST3 was the dominant subtype (41.9%, 13/31) being detected in NHPs. Of the 31 Blastocystis sp. isolates from the wild animals, 24 (77.4%) isolates belonged to the most common subtypes (ST1 to ST3) found in humans. This is the first molecular study of Blastocystis sp. in wild animals in Bangladesh. This study highlights the remarkable genetic diversity in Blastocystis sp. isolates from zoo animals and provides the first molecular evidence from spotted deer, gayal and grey langur. Due to circulation of large percentage of potentially zoonotic subtypes in the wild animals, there is a higher risk of zoonotic transmission of Blastocystis sp. in the zoo keepers and visitors.

Blastocystis sp. Subtype Diversity in Wild Carnivore Species from Spain

The occurrence and molecular diversity of the stramenopile eukaryote Blastocystis sp. was investigated by PCR and sequencing (Sanger and NGS) methods in 380 faecal specimens of free-living carnivores in Spain. Blastocystis sp. was confirmed in 1.6% (6/380) of the specimens analysed. Two samples from a common genet and a fox were successfully subtyped as ST7 by Sanger. Using NGS, ST14 was found in a fox and a European polecat, ST7 in a fox, and two additional foxes presented mixed infections of ST1/ST2/ST4 and ST1/ST2/ST7, respectively. Wild carnivore species could act as carriers of zoonotic Blastocystis subtypes.

Diversity of Blastocystis subtypes in wild mammals from a zoo and two conservation units in southeastern Brazil

The enteric protist Blastocystis is one of the most commonly parasite reported in humans and a variety of animal hosts worldwide. Regarding genetic diversity, at least 17 subtypes (STs) have been identified in mammals and birds, with eight of them (ST1-8) infecting both humans and animals. Recently, isolates from wild mammalian species have been genetically characterized, however data is still scarce, mainly in Latin America. Here, we aimed to verify the occurrence and genetic diversity of Blastocystis in captive wild mammals kept in one zoo and in two units of protection and conservation in southeastern Brazil. A total of 78 fecal samples (14 pooled and 64 individual samples) were recovered from 102 wild mammals of 35 species included in the following orders: Primates, Carnivora, Artiodactyla, Pilosa, Rodentia and Marsupialia. Zoo and units staff were invited to participated but only 16 fecal samples could be screened. Based on the sequence analyses of SSUrDNA gene, out of 29 PCR products from animal samples, 51.7% (15/29) were successfully sequenced and five Blastocystis subtypes were identified as follows: ST1 (2/15; 13.3%), ST2 (2/15; 13.3%), ST3 (4/15; 26.6%), ST5 (2/15; 13.3%) and ST8 (5/14; 33.3%). Only four isolates from humans were sequenced and identified as ST1 (2 isolates), ST2 and ST3. It was observed that Blastocystis infecting non-human primates belong to ST1 and ST2 and mainly to ST3 and ST8, artiodactyls ST5, carnivores ST1 and ST5 and rodents ST1. In addition, this present study reports some interesting findings: (1) 63% (12/19) of Blastocystis isolates from animals and employees belonged to the potentially zoonotic subtypes ST1-ST3; (2) most of these isolates displayed high identity with publicly available DNA sequences from non-human primates and humans, including primate handlers; (3) Blastocystis ST5 was found infecting the northern tiger cat, a native South American felid and one of the species facing a high risk of extinction in Brazil.

Molecular Detection and Subtyping of Blastocystis in Korean Pigs

Blastocystis is one of the most commonly detected genera of protozoan parasites in the human intestines as well as the intestines of many other species such as pigs in several geographical regions worldwide. However, no studies have examined Blastocystis in pigs in Korea. In this study, PCR and nucleotide sequencing were performed to evaluate the genetic diversity and zoonotic potential of Blastocystis using pig fecal samples. We obtained 646 stool samples from groups of piglets, weaners, growers, finishers, and sows in Korea. A total of 390 Blastocystis-positive samples were identified, and the infection rate was 60.4%. The infection rates were significantly related to age and region. The 4 subtypes (STs) of Blastocystis confirmed by phylogenetic analysis were ST1, ST2, ST3, and ST5, indicating the high genetic diversity of Blastocystis in Korean pigs. ST5 was highly distributed in Korean pigs among detected STs in this study. Some sequences were closely related to those of Blastocystis isolated from humans. This is the first study of Blastocystis in pigs in Korea. Based on the results, Blastocystis is prevalent in Korean pigs. Although a small number of samples were obtained in some areas, the clinical development of Blastocystis infection in pigs and potential for human transmission should be further examined.

Molecular Subtyping of Blastocystis from Diverse Animals in the United Arab Emirates

The contribution of Blastocystis from non-human hosts to zoonotic transmission is only partly known. The objective of this study was to determine the distribution of Blastocystis genetic subtypes in different animal species in United Arab Emirates. A total of 114 stool samples were tested using PCR of the small subunit (SSU) rRNA gene and sequence analysis. Twenty-three Blastocystis-positive samples were identified. The following detection rates were observed: cattle, 22.7%; sheep, 63.6%; rabbits, 33.3%; rodents, 37.5%; reptiles, 21.2%. Four subtypes were identified in this study; ST4, ST10, ST14, and ST17; ST10 was isolated from sheep and cattle, corroborating previous data indicating that these are natural hosts for this subtype. Cases of mixed subtype colonization were also detected. Conspicuously, we found ST14 in rabbits. The discovery of ST17 in a squirrel indicates a novel host for this subtype. Furthermore, the discovery of ST4 in rodents suggests that these may serve as reservoir for human Blastocystis ST4 colonization. Six tortoises and one iguana were positive for Blastocystis. In conclusion, this is the first report of Blastocystis infection in various animals in the UAE. Apart from ST4, no potentially zoonotic subtypes were detected.

Are molecular tools clarifying or confusing our understanding of the public health threat from zoonotic enteric protozoa in wildlife?

Emerging infectious diseases are frequently zoonotic, often originating in wildlife, but enteric protozoa are considered relatively minor contributors. Opinions regarding whether pathogenic enteric protozoa may be transmitted between wildlife and humans have been shaped by our investigation tools, and have led to oscillations regarding whether particular species are zoonotic or have host-adapted life cycles. When the only approach for identifying enteric protozoa was morphology, it was assumed that many enteric protozoa colonized multiple hosts and were probably zoonotic. When molecular tools revealed genetic differences in morphologically identical species colonizing humans and other animals, host specificity seemed more likely. Parasites from animals found to be genetically identical - at the few genes investigated - to morphologically indistinguishable parasites from human hosts, were described as having zoonotic potential. More discriminatory molecular tools have now sub-divided some protozoa again. Meanwhile, some infection events indicate that, circumstances permitting, some "host-specific" protozoa, can actually infect various hosts. These repeated changes in our understanding are linked intrinsically to the investigative tools available. Here we review how molecular tools have assisted, or sometimes confused, our understanding of the public health threat from nine enteric protozoa and example wildlife hosts (Balantoides coli - wild boar; Blastocystis sp. - wild rodents; Cryptosporidium spp. - wild fish; Encephalitozoon spp. - wild birds; Entamoeba spp. - non-human primates; Enterocytozoon bieneusi - wild cervids; Giardia duodenalis - red foxes; Sarcocystis nesbitti - snakes; Toxoplasma gondii - bobcats). Molecular tools have provided evidence that some enteric protozoa in wildlife may infect humans, but due to limited discriminatory power, often only the zoonotic potential of the parasite is indicated. Molecular analyses, which should be as discriminatory as possible, are one, but not the only, component of the toolbox for investigating potential public health impacts from pathogenic enteric protozoa in wildlife.

Higher prevalence of Blastocystis hominis in healthy individuals than patients with gastrointestinal symptoms from Ahvaz, southwestern Iran

BACKGROUND

Blastocystis, a common intestinal protozoan of humans and animals, infected more than 1 billion people around the world. This enteric protozoan is frequently reported in both healthy individuals and patients with gastrointestinal (GI) symptoms.

METHODS

Three hundred and forty-five fecal samples including 151 GI patients and 194 healthy individuals were examined by microscopy, culture and PCR-sequencing techniques to determine Blastocystis frequency and subtype (ST) variation.

RESULTS

The occurrence of Blastocystis was detected 56 (16.2%) and 85 (24.6%) by microscopy, culture and PCR methods, respectively. Out of the 85 positive patients, 60 (70.6%) were asymptomatic and 25 (29.4%) were symptomatic. The results of 41 successfully sequenced isolates identified 8 (19.5%), 8 (19.5%), and 25 (61.0%) ST1, ST2, and ST3, respectively.

CONCLUSION

This study has found that Blastocystis was more common in healthy individuals than GI patients. Another finding was that no correlation was found between clinical symptoms and Blastocystis STs.