Diagnosis and molecular typing of Enterocytozoon bieneusi: the significant role of domestic animals in transmission of human microsporidiosis

The global epidemiology of Microsporidia infection in birds: A systematic review and meta-analysis

This study aimed to assess the global status and genetic diversity of Microsporidia infection in different birds. An online search was conducted in international databases from 1 January 1990 to 30 June 2022. A total of 34 articles (including 37 datasets) were included for the final meta-analysis. The pooled global prevalence of Microsporidia infection in birds was 14.6% (95% CI: 11.6-18.1). The highest prevalence of Microsporidia was found in wild waterfowl which was 54.5% (28.1-78.6). In terms of detection methods, the pooled prevalence was estimated to be 21.2% (95% CI: 12.1-34.4) and 13.4% (95% CI: 10.3-17.3) for using microscopic and molecular detection methods, respectively. Enterocytozoon bieneusi was the most common pathogen (24/31; 77.42% of the studies) according to PCR-based methods, and genotype D was the highest reported genotype (nine studies). In conclusion, designing strategies for the control and prevention of Microsporidia infection in birds should be recommended.

Widespread distribution of human-infective Enterocytozoon bieneusi genotypes in small rodents in northeast China and phylogeny and zoonotic implications revisited

Enterocytozoon bieneusi features high genetic diversity among host species and environmental sources and over 500 genotypes in 11 phylogenetic groups have been defined. Here we investigated 291 small rodents in Heilongjiang province, northeast China, for the presence of E. bieneusi by PCR of the ribosomal internal transcribed spacer (ITS). Nine of 60 (15.0 %) gray squirrels from a park in Harbin, 120 of 201 (59.7 %) guinea pigs from a pet shop in Harbin, and two of 30 (6.7 %) peridomestic rats from a pasture in Qiqihar were positive for the parasite. Six known genotypes (EbpB, SCC-1, SCC-2, D, S7 and HLJ-CP1) and two novel genotypes (NESQ1 and NEGP1) were identified by sequence analysis of the ITS, with EbpB, SCC-1, SCC-2 and NESQ1 found in squirrels, D, S7 and NEGP1 in guinea pigs, and EbpB and HLJ-CP1 in rats. Widespread distribution of human-infective Group 10 genotype S7 and Group 1 genotype D in guinea pigs raised our concerns about the importance of pet animals as zoonotic reservoirs of microsporidiosis. Co-occurrence of Group 1 genotypes D and HLJ-CP1 in cancer patients and rodents in Heilongjiang indicated a possibility of zoonotic transmission. The host range of Group 1 genotype EbpB previously considered pig-adapted was extended. A potential variant of genotype S7, namely NESQ1, went into the existing Group 10 in phylogenetic analysis. The other new genotype, NEGP1, was clustered in an undefined clade we proposed as Group 15. With the emerging epidemiologic evidence, the host specificity of existing E. bieneusi genotypes is now being challenged.

Host-specific Cryptosporidium, Giardia and Enterocytozoon bieneusi in shelter dogs from central Europe

Cryptosporidium spp., Giardia intestinalis and microsporidia are unicellular opportunistic pathogens that can cause gastrointestinal infections in both animals and humans. Since companion animals may serve as a source of infection, the aim of the present screening study was to analyse the prevalence of these intestinal protists in fecal samples collected from dogs living in 10 animal shelters in central Europe (101 dogs from Poland and 86 from the Czech Republic), combined with molecular subtyping of the detected organisms in order to assess their genetic diversity. Genus-specific polymerase chain reactions were performed to detect DNA of the tested species and to conduct molecular subtyping in collected samples, followed by statistical evaluation of the data obtained (using χ2 or Fisher's tests). The observed prevalence was 15.5, 10.2, 1 and 1% for G. intestinalis, Enterocytozoon bieneusi, Cryptosporidium spp. and Encephalitozoon cuniculi, respectively. Molecular evaluation has revealed the predominance of dog-specific genotypes (Cryptosporidium canis XXe1 subtype; G. intestinalis assemblages C and D; E. cuniculi genotype II; E. bieneusi genotypes D and PtEbIX), suggesting that shelter dogs do not pose a high risk of human transmission. Interestingly, the percentage distribution of the detected pathogens differed between both countries and individual shelters, suggesting that the risk of infection may be associated with conditions typical of a given location.

Prevalence and genotype/subtype distribution of Enterocytozoon bieneusi and Blastocystis in donkeys in Shanxi Province, north China

Enterocytozoon bieneusi and Blastocystis may cause diarrhea in humans and various animals. However, little information is available regarding the prevalence and genetic diversity of E. bieneusi and Blastocystis in donkeys. To fill this gap, we molecularly assessed E. bieneusi and Blastocystis in fecal samples from donkeys (n = 815) in Shanxi Province, north China. The overall prevalence of E. bieneusi and Blastocystis in donkeys was 8.1% and 0.2%, respectively. Region and age were risk factors associated with E. bieneusi infection in donkeys. Three internal transcribed spacer (ITS) genotypes of E. bieneusi were identified in the current study, including two previously described genotypes (D and Henan-IV) and one novel genotype (named SXD1). Of which, genotype D was found to be the most prevalent. Phylogenetic analysis demonstrated that the three genotypes belonged to group 1, implying a potential of zoonotic transmission. Multilocus sequence typing showed that 19, 15, 13, and 22 types were identified at the loci MS1, MS3, MS4, and MS7, respectively, forming six multilocus genotypes (MLGs) distributed in the genotype D. One Blastocystis subtype (ST33) was identified, which has previously been reported only in horses. This is the first molecular-based description of E. bieneusi and Blastocystis infections in donkeys in Shanxi Province, north China, contributing to a better understanding of transmission dynamics and molecular epidemiological characteristics of the two intestinal protozoa.

Microscopic and Molecular Investigation of Intestinal Microsporidia in HIV + /AIDS and Cancer Patients Undergoing Chemotherapy in Mazandaran Province, North of Iran

BACKGROUND

The aim of this study was to identify Enterocytozoon bieneusi and Encephalitozoon spp. in fecal samples of HIV + /AIDS and cancer patients undergoing chemotherapy, and comparing the results to healthy individuals in Mazandaran province, north of Iran.

METHODS

Stool samples were collected from 50 HIV + /AIDS patients, 50 cancer patients, and 50 healthy samples referred to medical centers in north of Iran. Stool samples were kept in 2.5% potassium dichromate at 4 °C, and stained by modified trichrome for light microscopy examination. The multiplex/nested-PCR targeted the small subunit ribosomal RNA (SSU rRNA) gene. To characterize genotypes, the nested PCR products sequenced by Bioneer Company and was subjected to phylogenetic analyses.

RESULTS

Ten of 50 samples (20%) of HIV + /AIDS patients, 5 of 50 samples (10%) of cancer patients, and 1 of healthy individuals (2%) were microscopically positive. From 50 HIV + / AIDS patients, E. bieneusi and Encephalitozoon spp. were detected in 10 (20%) and 6 (12%) cases, respectively. Furthermore, among cancer patients, 7 (14%) and 2 (4%) cases were E. bieneusi and Encephalitozoon spp., respectively. Out of 50 samples of healthy individuals, only 3 (6%) cases of E. bieneusi were observed. The genotypes D and M were detected among positive samples of E. bieneusi.

CONCLUSIONS

E. bieneusi and then Encephalitozoon spp. are common intestinal microsporidia in HIV + /AIDS patients and cancer patients undergoing chemotherapy in Mazandaran province. E. bieneusi genotype D seems to be the predominant genotype in Mazandaran province. Due to the considerable prevalence of intestinal microsporidia, physicians are advised to pay more attention to this opportunistic infection in high-risk groups.

Exploring genetic variability of Giardia duodenalis and Enterocytozoon bieneusi in raw vegetables and fruits: implications for food safety and public health in Mozambique

Giardia duodenalis and Enterocytozoon bieneusi are etiological agents of enteric diseases characterized by diarrhea that can progress to chronicity in humans, especially in children and in immunocompromised patients. This study aims to assess the genetic pattern of G. duodenalis and E. bieneusi detected in vegetables and fruits commercialized in Maputo markets, Mozambique and determine their public health importance. Eight study points were sampled: a farmer zone, a wholesale, four retail markets, and two supermarkets in Maputo city, where eight types of horticultural products were purchased. Using nested-PCR methods, 2.8% (9/321) and 1.3% (4/321) of samples monitored were positive for G. duodenalis and E. bieneusi, respectively. Based on the analysis of the β-giardin and ITS rRNA sequences of G. duodenalis and E. bieneusi detected, respectively, four different sequences of G. duodenalis (three novel sequences: BgMZ1, BgMZ2, and BgMZ3, and one known sequence) all from assemblage B and three genotypes of E. bieneusi (two novel sequences: EbMZ4 and EbMZ5, and one known sequence: KIN-1) from group 1. These microorganisms were found and characterized for the first time in horticultural products in Maputo markets. All identified G. duodenalis and E. bieneusi display high genetic similarity within their β-giardin and ITS rRNA sequences, respectively, having been clustered into assemblages and genotypes with high zoonotic transmission potential. Our study may represent a relevant step in the understanding of these intestinal pathogens in association with fresh vegetables and fruits for human consumption, for a better and broader "One Health" approach.

First report on the molecular detection of Enterocytozoon bieneusi in livestock and wildlife around Qinghai Lake in the Qinghai-Tibetan Plateau area, China

Enterocytozoon bieneusi is considered to be a microsporidial species of humans and animals in the worldwide. Limited data have been reported on the prevalence and genotypes of E. bieneusi in livestock and wild animals around Qinghai Lake in the Qinghai-Tibetan Plateau area, which shares water sources, grasslands, and harsh climate with high altitudes. In this study, fecal samples from 110 Tibetan sheep, 128 yaks, 227 wild birds, 96 blue sheep (Pseudois nayaur) and 268 Przewalski's gazelle (Procapra przewalskii) around Qinghai Lake were collected, and then tested for E. bieneusi by PCR and sequencing analysis based on the ribosomal internal transcribed spacer. Among them, ten (9.09%) samples from Tibetan sheep, five (3.91%) from yaks, five (2.20%) from wild birds, one (1.04%) from wild blue sheep and two (0.75%) from Przewalski's gazelle were positive for E. bieneusi. Among sheep, there were nine E. bieneusi genotypes, including two known genotypes (BEB6 and J), and seven novel genotypes (named CHS18-CHS24). From yaks, four genotypes were identified, including two known ones (BEB4 and J) and two novel genotypes (named CHN15 and CHN16). While in wild animals, eight genotypes were found, including five different genotypes from wild bids, with three known genotypes (EbpC, J and NCF2), two novel genotypes (named CHWB1 and CHS24), and two genotypes from Przewalski's gazelle, with one known genotype J and one novel genotype CHWPG1, and one novel genotype CHWBS1 from blue sheep. According to the phylogenetic analysis, five isolates belonged to group 1, and the others were clustered into group 2. This study provides unique data on the epidemiological reports and potential risk factors for E. bieneusi in both domesticated livestock and wild animals around Qinghai Lake in the Qinghai-Tibetan Plateau area; it is important to better understand the molecular epidemiology and zoonotic potential of E. bieneusi in the Qinghai-Tibetan Plateau area.

Survey of Zoonotic Diarrheagenic Protist and Hepatitis E Virus in Wild Boar (Sus scrofa) of Portugal

Enteropathogenic parasites and viruses have been frequently reported in swine and can infect a wide range of mammals, including humans. Among the wide variety of parasites infecting swine, diarrhoeagenic protists are among those that cause significant morbidity. Hepatitis E virus (HEV) has also been reported both in domestic pigs and wild boar and is known to have an important public health significance. These agents share the fecal−oral transmission route, but data on their fecal shedding and circulation pathways are still lacking or incomplete. Hence, the aim of the present study was to characterize the presence of microeukaryotes and HEV in the wild boar of Portugal. Wild boar stool samples (n = 144) were obtained during the official hunting seasons (October to February) in 2018/2019, 2019/2020, and 2021/2022 and tested for Cryptosporidium spp., Balantioides coli, Giardia duodenalis, Blastocystis sp., Enterocytozoon bieneusi and HEV by molecular assays, followed by sequencing and phylogenetic analysis. We have detected Cryptosporidium scrofarum (1.4%, 95% CI: 0.2−4.9), B. coli (14.6%, 95% CI: 9.2−21.4), Blastocystis ST5 (29.2%, 95% CI: 21.9−37.2) and HEV genotype 3 (2.8%, 95% CI: 0.7−6.9; subgenotypes 3e and 3m). Co-infections were observed in thirteen animals where two were positive for both HEV and B. coli, one was positive for both C. scrofarum and Blastocystis ST5, and ten were positive for both B. coli and Blastocystis ST5. Giardia duodenalis and E. bieneusi were not detected in the surveyed wild boar population. As far as we know, this is the first report describing protist infections by Cryptosporidium spp., B. coli, and Blastocystis sp., as well as the first identification of the emerging HEV genotype 3m in wild boar of Portugal. The present work shows that potentially zoonotic protozoa and HEV are circulating in wild boar populations in Portugal. Awareness and epidemic-surveillance network implementation measures targeting wild boar are needed to prevent the spread of these pathogenic agents to humans.

Prevalence and genotyping distribution of Enterocytozoon bieneusi in diarrheic pigs in Chongqing and Sichuan provinces, China

The microsporidian fungal pathogen Enterocytozoon bieneusi is a unicellular parasite that infects humans and various animals, including pigs. Currently, there are few data on E. bieneusi infection a in diarrheic pigs in Chongqing and Sichuan Provinces, China. This study aims to determine the prevalence and genotype distribution of E. bieneusi in diarrheic pigs. In total, 514 fecal samples from diarrheic pigs were obtained from 14 large-scale farms in Chongqing and Sichuan Provinces (326 suckling pigs, 17 weaned pigs, 65 fattening pigs, and 106 sows). To identify the E. bieneusi genotypes, genomic DNA was isolated from the samples and tested by nested PCR, targeting the internal transcribed spacer region of the rRNA followed by DNA sequence analysis. The overall prevalence of E. bieneusi was 79.8% (410/514), with rates of 84.9% (90/106) in sows and 64.7% (11/17) in weaned pigs. We found 61 different genotypes, including seven known genotypes (E, F, CHG1, Peru8, CAF1, B, and BEB17) and 54 novel genotypes. These 54 new genotypes are variants of eight known genotypes (SDD2, A, B, HLJD-IV, PigSpEb1, O, JLD-I, and BEB17) based on their sequence similarities. Phylogenetically, all of the identified genotypes clustered with counterparts belonging to Group 1 and Group 2 of E. bieneusi. Therefore, we found a higher prevalence of E. bieneusi in sows than in preweaned and weaned pigs. These findings indicate that diarrheic pigs could be a potential reservoir host, which can contaminate the environment and be a source of microsporidia in humans and other animals.

Enterocytozoon bieneusi in patients with diarrhea and in animals in the northeastern Chinese city of Yichun: genotyping and assessment of potential zoonotic transmission

Enterocytozoon bieneusi is a common microsporidia species in humans and animals. Due to lack of effective vaccines and drugs, understanding of its epidemiological status and characteristics in different hosts is an important step in controlling the infection. The present study aimed at determining the prevalence of E. bieneusi in humans with diarrhea and animals in Yichun, in northeastern China, and assessing the epidemiological role of animals in the transmission of microsporidiosis. A total of 540 fecal samples were collected from diarrheal patients (n = 222) and 11 animal species (n = 318). Enterocytozoon bieneusi was identified and genotyped by polymerase chain reaction (PCR) and sequencing of the internal transcribed spacer (ITS) region of the rRNA gene. Enterocytozoon bieneusi was detected in 1.4% (3/222) of diarrheal patients, and genotype D and novel genotypes YCHH1 and YCHH2 were identified. Enterocytozoon bieneusi was detected in wild boars (7.7%), sika deer (8.2%), dogs (3.2%), and ostriches (10.7%), and genotypes D, Type IV, Peru6, BEB6 and novel genotypes YCHA1, YCHA2 and YCHA3 were identified. Genotypes YCHH1, YCHH2 and YCHA1 were phylogenetically assigned to group 1, while YCHA2 and YCHA3 to groups 2 and 11, respectively. The finding of genotype D in humans and animals, and the identification of zoonotic genotypes Peru6, Type IV, BEB6 in animal-derived E. bieneusi isolates indicate the potential of zoonotic transmission of microsporidiosis in the investigated area. The observation of the three novel genotypes in group 1 indicates their zoonotic potential.

Molecular Epidemiology and Genetic Diversity of Enterocytozoon bieneusi in Cervids from Milu Park in Beijing, China

Simple Summary

Enterocytozoon bieneusi is the most prevalent microsporidian species that can cause significant intestinal diseases in both humans and animals worldwide. This study investigated the overall E. bieneusi prevalence of 21.9% (47/215) in captive and free-ranging deer species in Beijing, China. Thirteen E. bieneusi genotypes including six known and seven novel genotypes were identified. These resources will provide the insights to understand the veterinary and public health and the transmission dynamics between animal environments and human ones.

Abstract

Enterocytozoon bieneusi is the most prevalent microsporidian species that can cause zoonotic diseases in humans and animals. Despite receiving increasing attention in relation to domestic animals, there has been limited information on the infection burden of E. bieneusi in cervids. Altogether, 215 fecal samples collected from four deer species in Beijing, China were examined by nested- Polymerase Chain Reaction (PCR)targeting the internal transcribed spacer (ITS) region. The overall prevalence of E. bieneusi in deer was 21.9% (47/215), with 30.0% (24/80) in Pere David’s deer, 27.3% (15/55) in fallow deer, 12.5% (5/40) in sika deer, and 7.5% (3/40) in Chinese water deer. Thirteen E. bieneusi genotypes were identified, including six known (HLJD-V, MWC_d1, BEB6, CGC2, JLD-XV, and HND-I) and seven novel genotypes (BJED-I to BJED-V, BJFD, and BJCWD). A phylogenetic analysis showed that 38.3% of the isolates belonged to zoonotic Group 1. In addition, E. bieneusi infection was first detected in fallow deer and Chinese water deer, which could act as potential zoonotic reservoirs. Our findings suggest that E. bieneusi circulates in deer and might be of importance to public health.

Current Therapy and Therapeutic Targets for Microsporidiosis

Microsporidia are obligate intracellular, spore-forming parasitic fungi which are grouped with the Cryptomycota. They are both opportunistic pathogens in humans and emerging veterinary pathogens. In humans, they cause chronic diarrhea in immune-compromised patients and infection is associated with increased mortality. Besides their role in pébrine in sericulture, which was described in 1865, the prevalence and severity of microsporidiosis in beekeeping and aquaculture has increased markedly in recent decades. Therapy for these pathogens in medicine, veterinary, and agriculture has become a recent focus of attention. Currently, there are only a few commercially available antimicrosporidial drugs. New therapeutic agents are needed for these infections and this is an active area of investigation. In this article we provide a comprehensive summary of the current as well as several promising new agents for the treatment of microsporidiosis including: albendazole, fumagillin, nikkomycin, orlistat, synthetic polyamines, and quinolones. Therapeutic targets which could be utilized for the design of new drugs are also discussed including: tubulin, type 2 methionine aminopeptidase, polyamines, chitin synthases, topoisomerase IV, triosephosphate isomerase, and lipase. We also summarize reports on the utility of complementary and alternative medicine strategies including herbal extracts, propolis, and probiotics. This review should help facilitate drug development for combating microsporidiosis.

A Perspective on the Molecular Identification, Classification, and Epidemiology of Enterocytozoon bieneusi of Animals

The microsporidian Enterocytozoon bieneusi is an obligate intracellular pathogen that causes enteric disease (microsporidiosis) in humans and has been recorded in a wide range of animal species worldwide. The transmission of E. bieneusi is direct and likely occurs from person to person and from animal to person via the ingestion of spores in water, food, or the environment. The identification of E. bieneusi is usually accomplished by molecular means, typically using the sequence of the internal transcribed spacer (ITS) region of nuclear ribosomal DNA. Currently, ~820 distinct genotypes of E. bieneusi have been recorded in at least 210 species of vertebrates (mammals, birds, reptiles, and amphibians) or invertebrates (insects and mussels) in more than 50 countries. In this chapter, we provide a perspective on (1) clinical aspects of human microsporidiosis; (2) the genome and DNA markers for E. bieneusi as well as molecular methods for the specific and genotypic identification of E. bieneusi; (3) epidemiological aspects of E. bieneusi of animals and humans, with an emphasis on the genotypes proposed to be zoonotic, human-specific, and animal-specific; and (4) future research directions to underpin expanded molecular studies to better understand E. bieneusi and microsporidiosis.

Molecular detection and genotyping of Enterocytozoon bieneusi in captive foxes in Xinxiang, Central China and its impact on gut bacterial communities

Enterocytozoon bieneusi is a common gastrointestinal parasite that has a broad range of hosts, including birds, mammals, and even humans. The changes of gut bacterial communities have been demonstrated during the course of E. bieneusi. This study aimed to examine the infection status, and assess the zoonotic potential and influence of E. bieneusi on gut bacterial communities of captive foxes in Xinxiang, central China. Fecal samples were collected from 216 captive foxes, and amplification of the internal transcribed spacer (ITS) gene of each sample was performed by nested polymerase chain reaction. E. bieneusi was detected in 48 (22.2%) samples, and five previously reported genotypes CHN-F1 (n = 25), D (n = 18), BEB6 (n = 3), NCF2 (n = 1), and CHN-DC1 (n = 1) were identified, with CHN-F1 being the dominant genotype (25/48, 52.1%). Phylogenetic analysis further revealed that CHN-F1, D, NCF2, and CHN-DC1 genotypes belonged to the zoonotic group 1 of E. bieneusi, whereas BEB6 belonged to group 2. Moreover, sequencing and bioinformatics analysis of the V3-V4 region of 16S rRNA gene in five E. bieneusi-positive and five negative samples showed that gut microbial diversity was higher in the infected animals. In both groups, Firmicutes and Bacteroidetes were the two most abundant phyla, but the Firmicutes/Bacteroidetes ratio was lower in E. bieneusi-positive foxes (7.9:1) as compared with E. bieneusi-negative foxes (5:1). More importantly, at the phylum level, "beneficial bacteria" such as Firmicutes (1.6%) and Bacteroides (5.8%) increased, whereas "opportunistic pathogens" such as Fusobacteria (8.2%) decreased. Similarly, at the genus level, the pathogenic Clostridiaceae_Clostridium (10.0%) decreased, whereas the "beneficial bacteria" Lactococcus (6.6%) increased. These interesting phenomena warrant further investigation.

Molecular-Based Detection of Enterocytozoon bieneusi in Farmed Masked Palm Civets (Paguma larvata) in Hainan, China: A High-Prevalence, Specificity, and Zoonotic Potential of ITS Genotypes

Enterocytozoon bieneusi is a microsporidian and zoonotic species. This study investigated the prevalence and distribution of E. bieneusi genotypes in farmed masked palm civets using nested PCR, as well as assessed their zoonotic potential by phylogenetic analysis of the ITS region of the rRNA region. Here, we collected 251 fecal specimens from farmed masked palm civets (Paguma larvata) from the Hainan Island, China. In total, 128 of 251 samples were positive for E. bieneusi, with an average infection rate of 51.0%. Seventeen genotypes were identified including 12 known genotypes—HNR-VI (n = 56), SHR1 (n = 45), SHW7 (n = 6), KIN-1 (n = 3), D (n = 3), New1 (n = 3), EbpC (n = 2), CHC5 (n = 1), CHG19 (n = 1), CHN4 (n = 1), EbpA (n = 1), and Henan-III (n = 1)—and five novel genotypes (HNPL-I to HNPL-II; one each). Phylogenetic analysis categorized these genotypes into two groups. Thirteen of them were members of the zoonotic group 1, and the remaining four genotypes were in group 12. This study has shown that the infection rates of E. bieneusi in masked palm civets from Hainan were relatively high and provide baseline data to control and prevent microsporidiosis in farm-related communities. Therefore, infections in masked palm civets with zoonotic genotypes D, EbpC, CHN4, EbpA, KIN-1, and Henan-III should be considered potential threats to public health.

Molecular Detection and Characterization of Blastocystis sp. and Enterocytozoon bieneusi in Cattle in Northern Spain

Some enteric parasites causing zoonotic diseases in livestock have been poorly studied or even neglected. This is the case in stramenopile Blastocystis sp. and the microsporidia Enterocytozoon bieneusi in Spain. This transversal molecular epidemiological survey aims to estimate the prevalence and molecular diversity of Blastocystis sp. and E. bieneusi in cattle faecal samples (n = 336) in the province of Álava, Northern Spain. Initial detection of Blastocystis and E. bieneusi was carried out by polymerase chain reaction (PCR) and Sanger sequencing of the small subunit (ssu) rRNA gene and internal transcribed spacer (ITS) region, respectively. Intra-host Blastocystis subtype diversity was further investigated by next generation amplicon sequencing (NGS) of the ssu rRNA gene in those samples that tested positive by conventional PCR. Amplicons compatible with Blastocystis sp. and E. bieneusi were observed in 32.1% (108/336, 95% CI: 27.2–37.4%) and 0.6% (2/336, 95% CI: 0.0–1.4%) of the cattle faecal samples examined, respectively. Sanger sequencing produced ambiguous/unreadable sequence data for most of the Blastocystis isolates sequenced. NGS allowed the identification of 10 Blastocystis subtypes including ST1, ST3, ST5, ST10, ST14, ST21, ST23, ST24, ST25, and ST26. All Blastocystis-positive isolates involved mixed infections of 2–8 STs in a total of 31 different combinations. The two E. bieneusi sequences were confirmed as potentially zoonotic genotype BEB4. Our data demonstrate that Blastocystis mixed subtype infections are extremely frequent in cattle in the study area. NGS was particularly suited to discern underrepresented subtypes or mixed subtype infections that were undetectable or unreadable by Sanger sequencing. The presence of zoonotic Blastocystis ST1, ST3, and ST5, and E. bieneusi BEB4 suggest cross-species transmission and a potential risk of human infection/colonization.

Molecular epidemiology and genotype/subtype distribution of Blastocystis sp., Enterocytozoon bieneusi, and Encephalitozoon spp. in livestock: concern for emerging zoonotic infections

Intestinal parasitic infections have high prevalence rate in many regions especially in developing countries. The aim of this study was to determine the presence and genotype/subtype of some intestinal protozoa in livestock in Iran. Stool samples were collected from cattle, sheep, chickens, and horses. The presence of targeted parasites was evaluated using real-time PCR. Genotyping/subtyping of positive samples was characterized using sequencing of the ITS and barcoding region, respectively. Blastocystis sp., 27.7% (48/173) and Enterocytozoon bieneusi 26.0% (45/173) were the most frequent protozoa followed by Encephalitozoon spp., 0.57% (1/173). Cryptosporidium spp. were not detected among samples. Encephalitozoon spp., was detected only in chickens 2.2% (1/45). A statistically correlation was seen between animals and the prevalence of targeted protozoa. E. bieneusi genotypes I (9/38; 23.68%), BEB6 (22/38; 57.89%), D (6/38; 15.79%), and horse1 (1/38; 2.63%) were detected among samples. A statistically significant correlation was seen between the genotypes and animals (P ≤ 0.05). Blastocystis sp., ST1 (1/45; 2.22%), ST5 3/45; 6.66%), ST7 (1/45; 2.22%), ST10 (24/45; 53.33%), and ST14 (16/45; 35.55%) were characterized among samples. There was no significant correlation between certain subtypes and animals (P = 0.173). The presence of zoonotic potential genotypes of E. bieneusi in animals and zoonotic potential subtypes ST1 and ST7 among our samples provide a clue about the transmission dynamic of E. bieneusi and Blastocystis sp. between animals–animals and humans–animals.

First genotyping of Enterocytozoon bieneusi in plateau pikas (Ochotona curzoniae) from the Qinghai Plateau, Northwest China

Enterocytozoon bieneusi is considered the most common microsporidian species and is frequently detected in humans and various animals worldwide. However, information on E. bieneusi infection in plateau pikas (Ochotona curzoniae) is somewhat limited. Therefore, this study was conducted to determine the infection status and genotype characteristics of E. bieneusi in plateau pikas in China. A total of 33 fresh fecal samples were collected from plateau pikas captured on the Qinghai Plateau. By PCR assay and DNA sequencing of the ITS gene, 5 (15.2%, 5/33) isolates were diagnosed as positive. Sequence analysis revealed the presence of one known sheep-derived genotype, CHS17 (4/5), and a novel E. bieneusi genotype, CHPP1 (1/5), with maximum shared identity with the CHS17 genotype. Phylogenetically, these isolates were clustered into subgroup 1i of zoonotic group 1 with genotypes CHS17 and CHN14 from plateau ruminants, but the new CHP1 genotype formed a cluster separate from those genotypes. This is the first report of E. bieneusi in plateau pikas. The findings suggested that these animals might be potential reservoirs of zoonotic E. bieneusi, and transmission of the pathogen between plateau pikas and sheep probably occurs in the region.

Molecular detection and genotyping of Enterocytozoon bieneusi in pet dogs in Xinjiang, Northwestern China

Enterocytozoon bieneusi is an obligate intracellular parasitic fungi that infects a wide range of mammalian hosts. However, the literature is lacking information regarding the presence and diversity of E. bieneusi genotypes in domesticated dogs in Northwestern China. Fecal samples from 604 pet dogs were obtained in 5 cities (Urumqi, Korla, Hotan, Aksu, and Shihezi) in Xinjiang. Screening for E. bieneusi was performed, and isolates were genotyped via nested-PCR amplification of the internal transcribed spacer (ITS) of nuclear ribosomal DNA. The infection rate of E. bieneusi was 6.3% (38/604). The prevalence of E. bieneusi infections in adult animals (>1 year, 10.3%, 15/145) was higher than that in younger (≤1 year) dogs (5.0%, 23/459), which was statistically significant (p = 0.021). No significant difference was observed between the different collection sites or between sexes. Eight distinct genotypes were identified, including 5 known genotypes (PtEb IX, EbpC, D, CD9, and Type IV) and 3 novel genotypes (CD11, CD12, CD13). The most prevalent was genotype PtEb IX, being observed in 50.0% (19/38) of the samples, followed by EbpC (31.6%, 12/38), D (5.3%, 2/38), and the remaining genotypes (CD9, Type IV, CD11, CD12, and CD13) were observed in 1 sample (2.6%, 1/38) each. These findings suggest that genotypes PtEb IX and CD9 are canine host-adapted, and likely pose little risk of zoonotic transmission. Moreover, known zoonotic genotypes EbpC, D, and Type IV represent a public health concern and should undergo further molecular epidemiological investigation.

Parasitic Intestinal Protists of Zoonotic Relevance Detected in Pigs by Metabarcoding and Real-Time PCR

Several parasite species are shared between humans and pigs. We explored the application of next-generation sequencing-based metabarcoding supplemented with real-time PCR to fecal DNAs from 259 samples from 116 pigs in Denmark to detect and differentiate single-celled intestinal parasites of zoonotic relevance. Enterocytozoon bieneusi, Balantioides coli, and Giardia duodenalis were observed in 34/37 (92%), 148/259 (57%), and 86/259 (33%) samples, respectively. Entamoeba polecki ST1, E. polecki ST3, and Entamoeba hartmanni were detected in 104/259 (40%), 161/259 (62%), and 8/259 (3%) samples, respectively. Metabarcoding and real-time PCR detected Cryptosporidium in 90/259 (35%) and 239/259 (92%) of the samples, respectively, with Cryptosporidium suis and Cryptosporidium scrofarum observed in nearly equal proportions. Blastocystis subtypes 1, 3, 5, and 15 were found in 72 (28%), 6 (2%), 176 (68%), and 36 (14%) of 259 samples, respectively. Iodamoeba was identified in 1/259 samples (<1%), while none of 37 tested samples was positive for Dientamoeba fragilis. Our results illustrate how metabarcoding exemplifies a 'one-fits-many' approach to detecting intestinal single-celled parasites in feces supplemented with real-time PCR for selected parasites. Using metabarcoding with pathogen-specific assays may help detect emerging and previously underdetected pathogens and further elucidate the role of micro-eukaryotic parasites in human and animal health and disease.

Distribution and genotypic analysis of Enterocytozoon bieneusi from wild boars in Korea

Enterocytozoon bieneusi, an important microsporidian fungus, causes chronic diarrhea in humans and animals worldwide. Of the 502 fecal samples from wild boars, 13 were positive for the E. bieneusi internal transcribed spacer region, with a prevalence of 2.6%. Six E. bieneusi genotypes, D, EbpC, and four novel KWB1-KWB4, were identified with zoonotic potential. Genotypes D (subgroup 1a) and EbpC (subgroup 1d) were first reported in Korean swine and Korea, respectively; KWB1-KWB4 (subgroup 1e) were most prevalent in this study. Because zoonotic genotypes have been identified, E. bieneusi transmission through wild boars must be closely monitored for proper prevention and treatment, despite their low prevalence.

Zoonotic parasites in farmed exotic animals in China: Implications to public health

Several species of wild mammals are farmed in China as part of the rural development and poverty alleviation, including fur animals, bamboo rats, and macaque monkeys. Concerns have been raised on the potential dispersal of pathogens to humans and other farm animals brought in from native habitats. Numerous studies have been conducted on the genetic identity and public health potential of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in these newly farmed exotic animals. The data generated have shown a high prevalence of the pathogens in farmed wildlife, probably due to the stress from the short captivity and congregation of large numbers of susceptible animals. Host adaptation at species/genotype and subtype levels has reduced the potential for cross-species and zoonotic transmission of pathogens, but the farm environment appears to favor the transmission of some species, genotypes, and subtypes, with reduced pathogen diversity compared with their wild relatives. Most genotypes and subtypes of the pathogens detected appear to be brought in from their native habitats. A few of the subtypes have emerged as human pathogens. One Health measures should be developed to slow the dispersal of indigenous pathogens among farmed exotic animals and prevent their spillover to other farm animals and humans.

Molecular detection and genotypes of Enterocytozoon bieneusi in farmed mink (Neovison vison), blue foxes (Alopex lagopus), and raccoon dogs (Nyctereutes procyonoides) in Xinjiang, China

Enterocytozoon bieneusi is a zoonotic pathogen that infects a variety of hosts including humans, livestock, wildlife, companion animals, and birds, as well as being abundant in the environment. Humans and nonhuman animals could be infected with E. bieneusi via consumption of food or water that contains zoonotic and host-adapted genotypes. In this study, 288 fecal specimens were collected from farmed minks, blue foxes, and raccoon dogs, in Xinjiang, China. Enterocytozoon bieneusi was examined by PCR amplification based on sequence analysis of the internal transcribed spacer (ITS) region. The overall infection rate of E. bieneusi was 4.9% (14/288), with mink samples showing the highest infection rate (5.6%, 12/214), followed by blue foxes (2.9%, 1/35), and then raccoon dogs (2.6%, 1/39). Six E. bieneusi genotypes were identified, including D (n = 5), PigEBITS7 (n = 4), EbpA (n = 2), CAM5 (n = 1), WildBoar3 (n = 1), and a novel genotype XJMI-1 (n = 1). Phylogenetic analysis showed that all E. bieneusi genotypes belonged to group 1, which composed of over 300 genotypes and most of them have been identified in human and variety of animals, suggesting a risk of zoonotic transmission from farmed wildlife to humans.

Ecological and public health significance of Enterocytozoon bieneusi

Enterocytozoon bieneusi, a fungus-like protist parasite, causes symptomatic and asymptomatic intestinal infections in terrestrial animals and is also abundant in the environment. This parasite has been isolated from a variety of host types including humans, livestock, companion animals, birds, and wildlife, as well as the natural and urban environments including drinking source water, coastal water, recreational water, wastewater, vegetables in retail markets, and raw milk on farms. E. bieneusi exhibits high genetic diversity among host species and environmental sources and at least 500 genotypes have been identified thus far. Since its discovery in AIDS patients in 1985, scientists across the world have worked to demonstrate the natural history and public health potential of this pathogen. Here we review molecular typing studies on E. bieneusi and summarize relevant data to identify the potential sources of human and nonhuman infections and environmental contamination. This review also discusses the possible transmission routes of E. bieneusi and the associated risk factors, and advocates the importance of the One Health approach to tackle E. bieneusi infections.