Multilocus Typing of Enterocytozoon bieneusi in Pig Reveals the High Prevalence, Zoonotic Potential, Host Adaptation and Geographical Segregation in China

Investigating Enterocytozoon bieneusi in pigs farmed in Zhejiang Province, China: Occurrence, genotype identification, evolutionary analysis, and zoonotic risk assessment

Enterocytozoon bieneusi is a widespread intracellular fungus that can infect both humans and animals, making it a significant zoonotic threat. In the current study, a total of 208 fecal samples were assayed to investigate the prevalence of E. bieneusi in pigs reared in Zhejiang Province, China. Employing polymerase chain reaction (PCR) amplification techniques specifically designed to target the internal transcribed spacer (ITS) region of the small subunit ribosomal RNA (rRNA) gene, the results revealed that 78 samples (37.5 %) tested positive for the presence of E. bieneusi. A total of 19 different genotypes of E. bieneusi were detected. Nine of these genotypes were already known: EbpC (n = 36), KIN-1 (n = 10), PigEbITS7 (n = 8), EbpA (n = 6), Henan III (n = 3), PigEbITS5 (n = 2), Henan-IV (n = 1), EbpD (n = 1), and TypeIV (n = 1), and 10 were novel: ZJP-I to ZJP-X (one each). The present investigation revealed that all the nine known genotypes identified in pigs here, have also been previously discovered in humans. Additionally, the novel genotypes of E. bieneusi discovered here were all classified as belonging to Group 1. These findings suggest the potential for cross-species transmission between humans and pigs.

Enterocytozoon bieneusi in Wild Rats and Shrews from Zhejiang Province, China: Occurrence, Genetic Characterization, and Potential for Zoonotic Transmission

Globally, Enterocytozoon bieneusi has been detected in humans and various animal hosts. Wild rats and shrews have the potential to act as carriers of E. bieneusi, facilitating the parasite's transmission to humans and domestic animals. We aimed to investigate the prevalence of E. bieneusi in 652 wild rats and shrews from Zhejiang Province, China, by amplifying the internal transcribed spacer (ITS) region of rDNA through polymerase chain reaction (PCR). To determine animal species, we amplified the Cytochrome b (Cyt-b) gene in their fecal DNA using PCR. Furthermore, we determined the genotype of E. bieneusi by amplifying the ITS region of rDNA through PCR. Genetic traits and zoonotic potential were evaluated using similarity and phylogenetic analyses. Suncus murinus (n = 282) and five rat species, Rattus losea (n = 18), Apodemus agrarius (n = 36), Rattus tanezumi (n = 86), Rattus norvegicus (n = 155), and Niviventer niviventer (n = 75), were identified. The average infection rate of E. bieneusi was 14.1% (92/652) with 18.1% (51/282) in S. murinus and 11.1% (41/370) in rats (27.8% in R. losea, 22.2% in A. agrarius, 10.5% in R. tanezumi, 8.4% in R. norvegicus, and 8.0% in N. niviventer). Thirty-three genotypes were identified, including 16 known genotypes. The most commonly known genotypes were HNR-VI (n = 47) and Peru11 (n = 6). Type IV, KIN-1, SHW7, and HNPL-II were each found in two samples, while Macaque4, CH5, K, Henan-III, Henan-V, HNP-II, HNPL-I, HNPL-III, HNHZ-II, and HNHZ-III were each found in one sample. Additionally, 17 novel genotypes were discovered: WZR-VIII (n = 5), WZR-I to WZR-VII, WZR-IX to WZR-XII, and WZSH-I to WZSH-V (n = 1 each). Those 33 genotypes were divided into three groups: Group 1 (n = 25), Group 2 (n = 3), and Group 13 (n = 5). The initial report underscores the extensive occurrence and notable genetic diversity of E. bieneusi in wild rats and shrews from Zhejiang province, China. These results suggest that these animals play a pivotal role in the transmission of E. bieneusi. Furthermore, animals carrying the zoonotic genotypes of E. bieneusi pose a serious threat to residents.

Meta-analysis of the global prevalence and risk factors of Enterocytozoon bieneusi infection in pigs from 1999 to 2021

Enterocytozoon bieneusi (E. bieneusi), which is one of the most common microsporidia, has been identified as an important obligate intracellular pathogen that commonly colonizes in a variety of animal species and humans worldwide, including humans. In this study, the statistical analyses of E. bieneusi infection and prevalence were performed to clarify the relationship between different genotypes in different countries. The databases Chinese National Knowledge Infrastructure (CNKI), VIP Chinese Journal Database, Wanfang Data, PubMed, Web of Science and ScienceDirect were used for data collection. The research data were subjected to subgroup, univariate regression, and correlation, to reveal factors related to the high prevalence of E. bieneusi. A total of, 34 of the 498 articles published before April 2022 met the inclusion criteria. The global prevalence of E. bieneusi in pigs was 37.69% (5175/12672). The prevalence of E. bieneusi in nursery pigs was 58.87% (588/946). In developing countries and Asia, the highest prevalence of E. bieneusi in pigs were 37.62% (4752/11645) and 40.14% (4715/11345), respectively. Moreover, humans and pigs have been found to be infected with the same genotype of E. bieneusi in some cases, as evidenced by the consolidation of genotype information. The results showed that pigs are susceptible to E. bieneusi during the nursery period. The prevalence of E. bieneusi is high in developing countries, and its genotype prevalence varies in each country. Thus, it is essential to strengthen the health inspection of vulnerable groups and customs quarantine inspection.

A high genetic diversity of Enterocytozoon bieneusi in diarrheic pigs in southern China

Enterocytozoon bieneusi is an important pathogen that is responsible for over 90% of documented cases of human microsporidiosis worldwide, causing a threat to public health and husbandry development. In immunocompromised patients, it can cause persistent diarrhoea, wasting diathesis and malabsorption and developing life-threatening chronic diarrhoea. However, there was little information on the prevalence and multilocus genotypes of E. bieneusi in diarrheic pigs in three provinces of southern China. In this study, 1254 faecal samples of diarrheic pigs were collected from 37 pig farms in Hunan, Jiangxi, and Fujian provinces in southern China, and were investigated the prevalence and genotypes of E. bieneusi by nested polymerase chain reaction (PCR) based on the internal transcribed spacer (ITS) region of the nuclear ribosomal DNA gene. The overall prevalence of E. bieneusi was 5.7% (72/1254) in three provinces. Furthermore, the difference was statistically significant (p < 0.001) in the prevalence of E. bieneusi in age groups. ITS sequence analysis revealed that 13 E. bieneusi genotypes were identified, including 8 known genotypes (EbpC, n = 30; Henan-IV, n = 21; CH5, n = 6; EbpA, n = 3; KIN-1, n = 2; O, n = 1; GX3, n = 1; CHS5, n = 1) and 5 novel genotypes (JX1, n = 2; JX2, n = 1; JX3, n = 2; FJ1, n = 1; FJ2, n = 1), and the genotype EbpC was the preponderant genotype. Phylogenetic analysis indicated that all genotypes of E. bieneusi were clustered as the zoonotic group 1. Moreover, a high genetic diversity of E. bieneusi were identified in this study, which the 64, 57, 52 and 64 samples were identified by multilocus sequence typing (MLST) at MS1, MS3, MS4 and MS7 loci, respectively. Then, 45 samples were successfully amplified and sequenced at four loci, forming 41 distinct multilocus genotypes (MLGs). These findings suggest that diarrheic pigs may potentially threaten to transmit E. bieneusi to humans, revealing E. bieneusi genetic variability in diarrheic pigs in three provinces of southern China.

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.

Molecular Detection and Genotyping of Enterocytozoon bieneusi in Pigs in Shanxi Province, North China

Enterocytozoon bieneusi is a common opportunistic intestinal pathogen that can cause acute diarrhea in immunosuppressed humans and animals. Though E. bieneusi has been widely detected in pigs around the world, little is known of its prevalence and genotype distribution in pigs in Shanxi province, north China. In this study, a total of 362 fecal samples were collected from pigs in three representative counties in north, south, and central Shanxi province, China. The prevalence and genotypes of E. bieneusi were investigated by nested PCR amplification of the ribosomal internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene. Overall, the prevalence of E. bieneusi in pigs in Shanxi province was 54.70% (198/362). Statistical analysis showed the difference in prevalence was statistically significant between regions (χ2 = 41.94, df = 2, P &lt; 0.001) and ages (χ2 = 80.37, df = 1, P &lt; 0.001). In addition, 16 genotypes of E. bieneusi were identified in this study by sequence analysis of the ITS region, including 15 known genotypes (EbpC, EbpA, EbpB, pigEb4, PigEBITS5, I, Henan-I, G, WildBoar 7, SH10, EbpD, CHC5, PigSpEb1, PigSpEb2, and CHG19) and one novel genotype (designated as PigSX-1). Phylogenetic analysis revealed that 14 known genotypes and the novel genotype were clustered into Group 1, whereas genotype I belonged to Group 2. To the best of our knowledge, this is the first report on the prevalence and genotypes of E. bieneusi in pigs in Shanxi province. These findings enrich the genetic diversity of E. bieneusi and provide the baseline data for the prevention and control of E. bieneusi in pigs in the study regions.

Chronic Infections in Mammals Due to Microsporidia

Microsporidia are pathogenic organism related to fungi. They cause infections in a wide variety of mammals as well as in avian, amphibian, and reptilian hosts. Many microsporidia species play an important role in the development of serious diseases that have significant implications in human and veterinary medicine. While microsporidia were originally considered to be opportunistic pathogens in humans, it is now understood that infections also occur in immune competent humans. Encephalitozoon cuniculi, Encephalitozoon intestinalis, and Enterocytozoon bieneusi are primarily mammalian pathogens. However, many other species of microsporidia that have some other primary host that is not a mammal have been reported to cause sporadic mammalian infections. Experimental models and observations in natural infections have demonstrated that microsporidia can cause a latent infection in mammalian hosts. This chapter reviews the published studies on mammalian microsporidiosis and the data on chronic infections due to these enigmatic pathogens.

Prevalence of Blastocystis infection in free-range Tibetan sheep and Tibetan goats in the Qinghai-Tibetan Plateau in China

Blastocystis is one of the most common enteric parasites in humans and domestic animals. For Tibetan sheep and Tibetan goats, the traditional grazing methods still occupy a dominant position, and the close contact between humans and domestic animals increases the risk of infection by Blastocystis between herdsmen and livestock. However, less pertinent information is available for Tibetan sheep or Tibetan goats. In this study, 880 fecal specimens from Tibetan sheep and Tibetan goats were collected from 6 sampling sites in Tibet to test for Blastocystis using the polymerase chain reaction and sequencing analysis of the partial SSU rRNA gene. The infection rate of Blastocystis was 8.55% for Tibetan sheep (53/620) and 8.46% for Tibetan goats (22/260). The genetic analysis of 53 positive samples from Tibetan sheep identified 4 known subtypes (ST4, ST5, ST10, and ST14). Four known subtypes (ST1, ST5, ST6, and ST10) were identified in Tibetan goats. ST10 was the dominant subtype in Tibetan sheep and Tibetan goats, accounting for 65.33% (49/75) of total subtypes. ST1, ST4, ST5, and ST6 were recognized as belonging to zoonotic subtypes. This report provides a detailed data on the prevalence and subtype distribution of Blastocystis in Tibetan sheep and Tibetan goats in Tibet, which enriches the epidemiological data of Blastocystis infection in Tibetan sheep and Tibetan goats in China. Our results indicated that Tibetan sheep and Tibetan goats can be infected with multiple Blastocystis subtypes, including zoonotic subtypes. More research is needed among humans, livestock and wild animals in Tibet to better understand their role in the spread of Blastocystis. And, One Health measures need to be taken to control and prevent its zoonotic transmission.

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Tibetan sheep and Tibetan goats were examined the Blastocystis for the first time.

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Subtypes ST4, ST5, ST10, ST14 in Tibetan sheep and subtypes ST1, ST5, ST6, ST10 in Tibetan goats were identified separately.

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Four potential zoonotic subtypes (ST1, ST4, ST5, ST6) were detected in this article.

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.

Common occurrence of Enterocytozoon bieneusi genotypes SHR1 and PL2 in farmed masked palm civet (Paguma larvata) in China

Enterocytozoon bieneusi is a common pathogen in a broad range of vertebrate hosts. To assess the prevalence and genotypes of E. bieneusi in farmed masked palm civet (Paguma larvata), 537 fecal samples from seven provinces in China were tested by nested PCR of the polymorphic internal transcribed spacer (ITS) region. Among of all the samples, 60.0% (325/531) were positive for E. bieneusi, with the highest prevalence in Hebei province (85.0%). Sequence analysis revealed the presence of nine E. bieneusi genotypes, including four known genotypes (SHR1, PL2, PL4, CHG19) and five novel genotypes (PL12 to PL16). Genotypes SHR1 and PL2 were the most common genotypes in seven provinces. Phylogenetic analysis showed that three genotypes (CHG19, PL4 and PL16) were distributed to Group 1, and six genotypes (SHR1, PL2, PL12, PL13, PL14 and PL15) formed a novel clade, which was named group 12. Findings highlight the need to conduct additional research to elucidate the epidemiology of E. bieneusi in farmed masked palm civet.

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The overall infection rate of Enterocytozoon bieneusi was 60.0% (325/537) in farmed masked palm civet (Paguma larvata) in China.

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Nine genotypes were identified, including four known genotypes (SHR1, PL2, PL4, CHG19) and five novel genotypes (named as PL12 to PL16).

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Genotypes in farmed masked palm civet formed a novel clade which was named as group 12.

Occurrence and potentially zoonotic genotypes of Enterocytozoon bieneusi in wild rhesus macaques (Macaca mulatta) living in Nanwan Monkey Island, Hainan, China: a public health concern

BACKGROUND

Enterocytozoon bieneusi, a microsporidian species, is a zoonotic pathogen found in both humans and animals. Here, we determined the prevalence, explored the different genotypes of E. bieneusi in wild rhesus macaques (Macaca mulatta) (Hainan Island of China), and assessed their zoonotic potential.

METHODS

We collected 173 fecal specimens from wild rhesus macaques living in Nanwan Monkey Island, Hainan, China. Subsequently, we identified and genotyped E. bieneusi using nested PCR analysis amplification of the internal transcribed spacer region (ITS) of the rRNA gene. Lastly, a neighbor-joining tree was built based on gene sequences from the ITS region of E. bieneusi.

RESULTS

Of the 173 specimens from wild rhesus macaques, 26 (15%) were infected with E. bieneusi. We identified six genotypes of E. bieneusi, of which five were known: PigEBITS7 (n = 20), D (n = 2), Type IV (n = 1), Peru6 (n = 1), Henan-III (n = 1), and a novel genotype: HNM-IX (n = 1). From the phylogenetic analysis, the six genotypes identified here were all clustered into zoonotic group 1.

CONCLUSION

This study is the first report to detect E. bieneusi infection in wild rhesus macaques from Hainan, China. Human-pathogenic genotypes D, Henan-III, Peru6, PigEbITS7, and Type IV in the wild rhesus macaques support these animals infected with E. bieneusi have a public health significance.

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.

Genotyping and zoonotic potential of Cryptosporidium and Enterocytozoon bieneusi in pigs transported across regions in China

Cryptosporidium spp. and Enterocytozoon bieneusi are common and important enteric parasites that can infect humans and animals, causing diarrhoea and systemic diseases. The objectives of the present study were to examine the prevalence and genetic variations of Cryptosporidium and E. bieneusi in pigs transferred from northeastern China to Ningbo city in Zhejiang Province. Cryptosporidium spp. was detected in 0.9% (2/216) of these samples and belonged to the zoonotic species Cryptosporidium parvum. A high E. bieneusi infection rate (25.0%, 54/216) was observed in this study, with 7 possible novel ITS genotypes (JLNB-1 to JLNB-7) and 10 known genotypes (EbpA, CM11, H, CM6, pigEBITS1, EbpC, CS-4, pigEBITS5, CHS5, and Henan-Ⅳ) identified, and zoonotic EbpA was the dominant genotype. Genotypes H and pigEBITS1 were reported for the first time in pigs in China. Phylogenetic analysis indicated that all the genotypes found in these samples belonged to zoonotic group 1. These findings indicated the potential threat of Cryptosporidium and E. bieneusi to humans or the environment during cross-regional transportation. An effective management control system should be built to avoid parasitic transmission as well as other animal diseases while travelling across different regions. In further studies, attention should be given to the transmission routes and the role of pigs as a potential source of human Cryptosporidium and E. bieneusi infections in China.

Population genetic analysis suggests genetic recombination is responsible for increased zoonotic potential of Enterocytozoon bieneusi from ruminants in China

Enterocytozoon bieneusi is a zoonotic pathogen with worldwide distribution. Among the 11 established groups of E. bieneusi genotypes based on phylogenetic analysis of the ribosomal internal transcribed spacer (ITS), the human-infective potential and population genetics of the Group 1 genotypes from diverse hosts are well characterized. In contrast, Group 2 genotypes from ruminants have unclear population genetics, leading to poor understanding of their host range and zoonotic potential. In this study, we sequence-characterized 121 Group 2 isolates from dairy cattle, beef cattle, yaks, Tibetan sheep, golden takins, and deer from China at five genetic loci (ITS, MS1, MS3, MS4 and MS7), comparing with data from 113 Group 1 isolates from nonhuman primates. Except for MS7, most of the genetic loci produced efficient PCR amplification and high nucleotide identity between Groups 1 and 2 of E. bieneusi genotypes. In population genetic analyses of the sequence data, a strong linkage disequilibrium was observed among these genetic loci in the overall Group 2 population. The individual ITS genotypes (I, J and BEB4) within Group 2, however, had reduced linkage disequilibrium and increased genetic exchanges among isolates. There was only partial genetic differentiation between Group 1 and Group 2 genotypes, with some occurrence of genetic recombination between them. Genetic recombination was especially common between genotypes I and J within Group 2. The data presented indicate a high genetic identity between Group 1 and Group 2 genotypes of E. bieneusi, which could be responsible for the broad host range and high zoonotic potential of Group 2 genotypes in China. As there is no effective treatment against E. bieneusi, the One Health approach should be used in the control and prevention of zoonotic transmission of the pathogen.

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

Enterocytozoon bieneusi is an obligate intracellular fungus-like parasite with high genetic diversity among mammalian and avian hosts. Based on polymorphism analysis of the ribosomal internal transcribed spacer (ITS), nearly 500 genotypes were identified within E. bieneusi. Those genotypes form several genetic groups that exhibit phenotypic differences in host specificity and zoonotic potential and probably have varying public health implications. Some of the genotypes in Group 1 (e.g., D, EbpC, and Type IV) and Group 2 (e.g., BEB4, BEB6, I, and J) are the most common ones that infect a variety of hosts including humans and thus are of public health importance. By contrast, those genotypes in other genetic groups (Groups 3-11) are mostly restricted to the hosts from which they were originally isolated, which would have unknown or limited impacts on public health. Advances on diagnosis and molecular typing of E. bieneusi are introduced in this review. Genotype distribution pattern of E. bieneusi in major domestic animal groups (pigs, cattle, sheep, goats, cats, and dogs), the role of those animals in zoonotic transmission of microsporidiosis, and food and water as potential vehicles for transmission are interpreted here as well. This review highlights the importance of including more genetic or epidemiological data obtained in the same geographical areas and using more reliable genetic markers to analyze the actual extent of host specificity in E. bieneusi, for the purpose of fully appreciating zoonotic risks of those domestic animals in close contacts with men and enhancing our understanding of the modes of transmission.

Multilocus Sequence Typing of Enterocytozoon bieneusi Isolates From Various Mammal and Bird Species and Assessment of Population Structure and Substructure

Enterocytozoon bieneusi is one of the most common intestinal pathogens in humans and animals. E. bieneusi has been confirmed to be complex microsporidian species. Approximately 500 ITS genotypes of E. bieneusi have been defined. With the establishment and application of multilocus sequencing typing and population genetic tools in E. bieneusi, the studies on these aspects have been carried out worldwide, but little information is available. To understand genetic variation of mini-/micro-satellites and the population structure and substructure of E. bieneusi in northeastern China, 305 E. bieneusi DNA specimens composed of 28 ITS genotypes were from 13 mammal species and five bird species in the investigated areas. They were characterized by nested-PCR amplification and sequencing at four mini-/micro-satellite loci (MS1, MS3, MS4, and MS7). At the MS1, MS3, MS4, and MS7 loci, 153 (50.16%), 131 (42.95%), 133 (43.61%), and 128 (41.97%) DNA specimens were amplified and sequenced successfully with 44, 17, 26, and 24 genotypes being identified, respectively. Multilocus genotypes (MLGs) showed a higher genetic diversity than ITS genotypes. 48 MLGs were produced out of 90 ITS-positive DNA specimens based on concatenated sequences of all the five genetic loci including ITS. Linkage disequilibrium (LD) and limited genetic recombination were observed by measuring LD using both multilocus sequences and allelic profile data, indicating an overall clonal population structure of E. bieneusi in the investigated areas. These data will aid in the longitudinal tracking of the attribution of source of infection/contamination and in elucidating transmission dynamics, and will provide valuable information for making efficient control strategies to intervene with and prevent occurrence of microsporidiosis caused by E. bieneusi among animals and transmission of E. bieneusi from animals to humans in the investigated areas. Phylogenetic and network analyses identified three different subgroups, revealing the presence of host-shaped segregation and the absence of geographical segregation in E. bieneusi population. Meanwhile, the MLGs from zoonotic ITS genotypes were observed to be basically separated from the MLGs from host-adapted ones. Assessment of substructure will have a reference effect on understanding of zoonotic or interspecies transmission of E. bieneusi and evolution direction from zoonotic genotypes to host-adapted genotypes.

Occurrence, risk factors and genotypes of Enterocytozoon bieneusi in dogs and cats in Guangzhou, southern China: high genotype diversity and zoonotic concern

Background

Enterocytozoon bieneusi, a common opportunistic fungal pathogen, has a wide range of hosts. Limited epidemiological data on E. bieneusi intestinal infections in companion animals (dogs and cats) in China exists. In this study, fecal samples (651 from dogs and 389 from cats) in Guangzhou city, Guangdong Province, China, were collected, and the ribosomal internal transcribed (ITS) spacer region from the DNA extracted from them was Polymerase Chain Reaction (PCR)-amplified and sequenced.

Results

Based on the sequencing data, E. bieneusi was identified in the fecal samples collected from 149 (22.9%) and 79 (20.3%) dogs and cats. Of the factors investigated, poor living conditions appeared to be the major risk factor for contracting the pathogen. Eleven E. bieneusi genotypes, six known (PtEb IX, GD1, D, CD9, EbpC, I) and five novel (designated here as GD2– GD6), were found in dogs. Eight genotypes, six known (PtEb IX, GD1, D, CD9, EbpC, Type IV) and two novel (GD2 and GC1), were identified in cats. Genotype PtEb IX was most common in both dogs and cats, followed by genotype GD1.

Conclusions

Although PtEb IX was the most common E. bieneusi genotype in dogs, this is the first report of this genotype dominating in cats. The same genotype distribution of the pathogen between the two different companion animals species in the same geographic area indicates that inter-species transmission is probable. The widespread existence of zoonotic E. bieneusi genotypes (D, EbpC, Type IV) in companion animals indicates that they are potential sources of environmental contamination and infections in humans.

Molecular characterization and novel genotypes of Enterocytozoon bieneusi in pet snakes in Beijing, China

Little is known regarding the Enterocytozoon bieneusi genotypes in snakes worldwide. In the present study, a total of 273 fecal samples were collected from pet snakes in Beijing, China. They were then tested for the presence of E. bieneusi by PCR amplification of the internal transcribed spacer (ITS) gene. The overall infection rate of E. bieneusi was 4.4% (12/273), with the highest infection rate (20%, 1/5) of E. bieneusi was found in the Black rat snake (Pantherophis obsoletus), whereas no positive samples were detected from both Milk (0/22) and Coast garter snakes (0/2). Eight genotypes were identified, including four known genotypes: EbpA (n = 1), EbpC (n = 5), Henan-III (n = 1), and SHR1 (n = 1), and four novel genotypes: CRep-5 (n = 1), CRep-6 (n = 1), CRep-7 (n = 1), and CRep-8 (n = 1). Among them, EbpC (41.7%, 5/12) was the predominant genotype. Phylogenetic analysis showed that seven genotypes belonged to group 1, while genotype SHR1 belonged to group 2. Genotypes EbpA, EbpC, and Henan-III have been previously reported in humans. This suggests that pet snakes are a potential source of zoonotic microsporidiosis transmission in China.

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4.4% (12/273) of pet snakes were PCR positive for E. bieneusi.

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Eight genotypes were identified, including four known and four novel genotypes.

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Transmission of E. bieneusi to humans from pet snakes is possible.

Enterocytozoon bieneusi (Microsporidia): Identification of novel genotypes and evidence of transmission between sympatric wild boars (Sus scrofa ferus) and Iberian pigs (Sus scrofa domesticus) in Southern Spain

Microsporidia is a phylum of obligate emergent intracellular protist-like fungi pathogens that infect a broad range of hosts including vertebrates and invertebrates. Enterocytozoon bieneusi is the most common cause of microsporidiosis in humans, affecting primarily immunosuppressed patients but also reported in immunocompetent individuals. Epidemiological information on the presence and molecular diversity of E. bieneusi in livestock and wildlife in Spain is limited. Therefore, the occurrence of this microsporidia was investigated in sympatric extensively reared Iberian pigs (n = 186) and free ranging wild boars (n = 142) in the province of Córdoba, Southern Spain. Forty-two Iberian pigs (22.6%) and three wild boars (2.1%) were found E. bieneusi positive by PCR. In Iberian pigs, occurrence of E. bieneusi was significantly higher in sows than in fattening pigs (31.6% vs. 11.4%; p = .001). Five genotypes were identified in Iberian pigs, four previously reported (EbpA, PigEb4, O, Pig HN-II) and a novel genotype (named PigSpEb1), while only two genotypes were identified in wild boars, EbpA and novel genotype PigSpEb1. All five genotypes identified belong to Group 1 suggesting zoonotic potential. This study constitutes the first report on the occurrence and molecular characterization of E. bieneusi in Iberian pigs and wild boars. The identification of two genotypes with zoonotic potential in sympatric Iberian pigs and wild boars suggests that E. bieneusi can be potentially transmitted between those two hosts, but also implies that they may act as natural sources of microsporidia infection to other hosts including humans.

Intestinal microsporidia infection among cat owners and non-pet owners in Iran: a case-control study

Microsporidia is a group of spore-forming microorganisms with zoonotic potential. This study aimed to compare intestinal microsporidia infections in cat owners and non-pet owners. In total, 210 fecal samples were collected from indoor cats, cat owners, and non-pet owners. DNA extraction was performed and the small subunit ribosomal RNA (SSU rRNA) gene was amplified. To characterize the genotypes, the internal transcribed spacer (ITS) fragment was amplified and sequenced. The phylogenetic trees were drawn to evaluate the relationship among Enterocytozoon bieneusi isolates. Two (2.9%) and one (1.4%) fecal samples from cat owners and one (1.4%) and two (2.9%) fecal samples from non-pet owners were positive for E. bieneusi and Encephalitozoon intestinalis, respectively. E. bieneusi was detected in two cat samples (2.9%). Same infection was not seen between infected cats and their owners. There was no significant difference between the prevalence rate of microsporidia among the cat owners and non-pet owners. Indeed, the genotypes L and type IV were seen in cats, while the genotype D was only detected in human. In this study, E. bieneusi and E. intestinalis were more prevalent among the cat owners and non-pet owners, respectively. Indeed, the higher prevalence of E. bieneusi in cats and their owners might be resulted from the worldwide distribution of this species.

Multilocus sequence typing of Enterocytozoon bieneusi in crab-eating macaques (Macaca fascicularis) in Hainan, China

Background

Enterocytozoon bieneusi is one of common intestinal pathogens in humans and animals including non-human primates (NHPs). Many zoonotic pathogens including E. bieneusi have been found in these animals. However, there are few studies on the population structure of E. bieneusi in NHPs. To infer the gene diversity and population genetics of E. bieneusi, we selected 88 E. bieneusi-positive samples from crab-eating macaques for multilocus characterizations in this study.

Methods

The E. bieneusi isolates examined belonged to three common genotypes with different host ranges by sequence analysis of the ribosomal internal transcribed spacer (ITS): Type IV (n = 44), Macaque3 (n = 24) and Peru8 (n = 20). They were further characterized by sequence analysis at four microsatellite and minisatellite loci (MS1, MS3, MS4 and MS7). DnaSP, Arlequin and LIAN were used to analyze the sequence data together with those from the ITS locus to infer the population genetics. Subpopulation structure was inferred using phylogenetic and STRUCTURE analyses.

Results

Seventy-two (81.8%), 71 (80.7%), 76 (86.4%) and 79 (89.8%) samples were amplified and sequenced successfully at the MS1, MS3, MS4 and MS7 loci, respectively, with 53 having sequence data at all five MLST loci including ITS. Altogether, 33 multilocus genotypes (MLGs) were produced based on concatenated sequences from the 53 samples. In phylogenetic analyses of sequences and allelic data, four major subpopulations (SPs) were observed with different ITS genotypes in each of them: Type IV and Peru8 in SP1 and SP2; Type IV, Macaque3 and Peru8 in SP3; and Type IV and Macaque3 in SP4. SP3 and SP4 were phylogenetically related and might be NHP-specific based on the fact that Macaque3 is mostly found in NHPs. A strong linkage disequilibrium (LD) was observed among the multilocus sequences and allelic data.

Conclusions

The significant LD in the multilocus sequence analysis indicated the presence of an overall clonal population structure of E. bieneusi in crab-eating macaques. The inconsistent segregation of MLGs among ITS genotypes suggested some occurrence of genetic recombination. These observations should improve our understanding of the population genetics of E. bieneusi in NHPs.

Molecular detection of Enterocytozoon bieneusi in farm-raised pigs in Hainan Province, China: infection rates, genotype distributions, and zoonotic potential

Enterocytozoon bieneusi is a zoonotic fungal pathogen with a high degree of host diversity that can parasitize many animals, including humans. Pigs may play an important role in the epidemiology of E. bieneusi as reservoir hosts. Nevertheless, the genotypes of E. bieneusi in pigs in China remain poorly understood. The aim of this study was to determine the prevalence of E. bieneusi infection amongst pigs raised on farms from four cities of Hainan Province, using nested polymerase chain reaction (PCR) of the partial small subunit of the ribosomal RNA gene, and to identify genotypes of E. bieneusi isolates based on sequence analysis of the ribosomal internal transcribed spacer (ITS) region. Among 188 stool samples, E. bieneusi was detected in 46.8% (88/188). Eight genotypes including four known (EbpA, CS-4, MJ14, and CHG19) and four novel (HNP-I – HNP-IV) genotypes were identified. Using phylogenetic analysis, genotypes EbpA, CS4, CHG19, HNP-III, and HNP-IV were clustered into zoonotic Group 1, while the remaining three genotypes (MJ14, HNP-I, and HNP-II) clustered into Group 10. The high prevalence of zoonotic genotypes of E. bieneusi among pigs suggests that pig farming is a potential source of human infection. Additionally, this is the first identification of genotypes in Group 10 in pigs indicating unique epidemic features of E. bieneusi in pigs in Hainan Province, the southernmost part of China.

Genotyping and Zoonotic Potential of Enterocytozoon bieneusi in Pigs in Xinjiang, China

Enterocytozoon bieneusi is an obligate intracellular fungus, infecting various invertebrate and vertebrate hosts, it is common in humans and causes diarrhea in the immunocompromised. In the present study, 801 fecal specimens were collected from pigs on seven large-scale pig farms in Xinjiang, China. Nested polymerase chain reaction (PCR) amplification of the internal transcribed spacer (ITS) gene showed that the overall E. bieneusi infection rate was 48.6% (389/801). The E. bieneusi infection rates differed significantly among the collection sites (20.0–73.0%) (χ² = 75.720, df = 6, p < 0.01). Post-weaned pigs had the highest infection rate (77.2%, 217/281), followed by fattening pigs (67.4%, 87/129) and pre-weaned suckling pigs (35.5%, 60/169). Adult pigs had the lowest infection rate (11.3%, 25/222). The E. bieneusi infection rates also differed significantly among age groups (χ² = 246.015, df = 3, p < 0.01). Fifteen genotypes were identified, including 13 known genotypes (CHC, CS-1, CS-4, CS-7, CS-9, D, EbpA, EbpC, EbpD, H, PigEb4, PigEBITS5, and WildBoar8) and two novel genotypes (XJP-II and XJP-III). Among them, six genotypes (CS-4, D, EbpA, EbpC, H, and PigEBITS5) have been reported in humans. Phylogenetic analysis showed that all the genotypes belonged to Group 1 of E. bieneusi. These findings suggest that pigs may play an important role in transmitting E. bieneusi infections to humans.

Molecular Detection, Multilocus Genotyping, and Population Genetics of Enterocytozoon bieneusi in Pigs in Southeastern China

Enterocytozoon bieneusi is an important opportunistic pathogen widely distributed in humans and animals that causes diarrhea or fatal diarrhea in immunocompromised hosts. To examine the infection status and molecular characteristics of E. bieneusi in pigs, 725 fecal samples were collected from pigs in six areas of Fujian Province. The E. bieneusi genotypes were identified based on the internal transcribed spacer (ITS) regions of the ribosomal RNA (rRNA) gene by nested PCR, and its population genetics were analyzed by multilocus sequence typing (MLST). The results showed that the infection rate of E. bieneusi was 24.4% (177/725), and 11 known genotypes (EbpC, EbpA, CHN-RR2, KIN-1, CHG7, CHS5, CM11, CHG23, G, PigEBITS, and D) and 2 novel genotypes (FJF and FJS) were identified. All the genotypes were found to be clustered into zoonotic Group 1. Moreover, 52 positive samples were successfully amplified at minisatellite and microsatellite loci and formed 48 distinct multilocus genotypes (MLGs). Further population structure analyses showed strong genetic linkage disequilibrium (LD) and several recombination events (Rm), indicating that E. bieneusi has a clonal population structure. This study is the first to investigate the prevalence and molecular characteristics of E. bieneusi in Fujian Province and could provide baseline data to control E. bieneusi infection in pigs and humans and deepen our understanding of the zoonotic risk of E. bieneusi and its distribution in China.

Prevalence and Population Genetics Analysis of Enterocytozoon bieneusi in Dairy Cattle in China

Enterocytozoon bieneusi, an obligate intracellular pathogen, can infect various hosts. In this study, 3527 dairy cattle fecal specimens were collected from different geographic locations in China (including 673 from Shandong province, 1,440 from Guangdong province and 1,414 from Gansu province) and examined for the presence of E. bieneusi using polymerase chain reactions targeting the ribosomal internal transcribed spacer (ITS). The dominant genotypes identified were further subtyped by multilocus sequence typing. The overall prevalence of E. bieneusi was 14.2% (501/3527), with a significant difference in prevalence among the different geographical locations (P < 0.001). Our logistic regression analysis showed that all four variables (farming model, location, age, and clinical manifestations) had strong effects on the risk of contracting E. bieneusi. Sequence analysis revealed 11 genotypes: eight known genotypes (J, I, BEB4, BEB10, D, EbpC, CM19, and CM21) and three novel genotypes (named here as CGC1, CGC2, and CGC3). Genotypes J and I, the commonest, were found on all farms across the three provinces. Our linkage disequilibrium analysis showed a clonal population structure in the E. bieneusi dairy cattle population but the ITS genotypes had different population structures. Phylogenetic and haplotype network analysis showed the absence of geographical segregation in the E. bieneusi dairy cattle populations. Instead, they revealed the presence of host adaptation to the E. bieneusi populations in various animals. Our findings augment the current understanding of E. bieneusi transmission dynamics.