Identification of Enterocytozoon bieneusi in goats and cattle in Thailand

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.

Global prevalence and risk factors of Enterocytozoon bieneusi infection in humans: a systematic review and meta-analysis

Enterocytozoon bieneusi is one of the most important zoonotic pathogens. In this study, we present a systematic review and meta-analysis of the prevalence of human E. bieneusi infection in endemic regions and analyze the various potential risk factors. A total of 75 studies were included. Among 31,644 individuals tested, 2,291 (6.59%) were E. bieneusi-positive. The highest prevalence of E. bieneusi in the male population was 5.50%. The prevalence of E. bieneusi in different age groups was varied, with 10.97% in teenagers. The prevalence of E. bieneusi in asymptomatic patients (6.49%) is significantly lower than that in HIV-infected patients (11.49%), and in patients with diarrheal symptoms (16.45%). Rural areas had a higher rate (7.58%) than urban ones. The prevalence of E. bieneusi in humans was the highest (6.42%) at altitudes <10 m. Moreover, the temperate zone marine climate (13.55%) had the highest prevalence. A total of 69 genotypes of E. bieneusi have been found in humans. This is the first global study regarding E. bieneusi prevalence in humans. Not only people with low immunity (such as the elderly, children, people with HIV, etc.), but also people in Europe in temperate marine climates should exercise caution to prevent infection with E. bieneusi during contact process with animals.

Occurrence and Phylogenetic Analysis of Zoonotic Enteropathogenic Protist Parasites in Asymptomatic Domestic Ruminants from Portugal

Enteropathogenic parasites are of significant concern for public health due to their zoonotic potential and their impact on human and animal health. In this study, we investigated their occurrence and characterized these enteropathogens in asymptomatic domestic ruminants from Portugal. A total of 302 stool samples were collected from cattle (n = 166), sheep (n = 73), and goats (n = 63) in various regions of Portugal and tested for Cryptosporidium spp., Giardia duodenalis, Enterocytozoon bieneusi, Blastocystis sp., and Balantioides coli by PCR. The occurrence of Cryptosporidium spp. was found to be 12.7% (8/63, 95% confidence interval [CI]: 5.65-23.5) in goats; however, no sample was found to be positive for Cryptosporidium spp. in cattle and sheep. For E. bieneusi, 6.35% (4/63; 95%CI: 1.76-15.47) of goats were found to be positive; however, no cattle or sheep were found to be positive. Blastocystis sp. was found in sheep (9.59%; 7/73; 95% [CI]: 0.394-18.76) and goats (12.70%; 8/63; 95% [CI]: 5.65-23.50) but none was found in cattle. No positive results for G. duodenalis or B. coli were detected in this study. This study provides essential baseline information for understanding the silent shedding and epidemiology of these enteropathogens in Portugal, contributing to overall livestock health and related occupational safety. Raising awareness among consumers, veterinarians, and farm owners is crucial to minimize the risk of transmission and promote effective disease control strategies.

Occurrence and Genotypic Identification of Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis in Leizhou Black Goats in Zhanjiang City, Guangdong Province, China

Blastocystis spp., Enterocytozoon bieneusi, and Giardia duodenalis are three common zoonotic intestinal parasites that cause severe diarrhea and enteric diseases. Leizhou black goats are characterized by a high reproductive rate, fast growth, and good meat quality, making them one of the pre-eminent goat breeds in China. Goats are reportedly common reservoirs of these three intestinal pathogens, but no information on their prevalence or genotypic distributions in black goats in Guangdong Province, China, is available. A total of 226 fecal samples were collected from goats in Zhanjiang city and genomic DNA was extracted from them. The presence of the three pathogens was detected using nested PCR targeting the sequences encoding SSU rRNA (Blastocystis spp.), the internal transcribed spacer of rRNA (ITS; E. bieneusi), as well as beta-giardin, glutamate dehydrogenase, and triosephosphate isomerase (G. duodenalis). All PCR products were sequenced to determine the species and genotypes of the organisms. The total prevalence rates of Blastocystis spp., E. bieneusi, and G. duodenalis were 33.63% (76/226), 17.70% (40/226), and 24.78% (56/226), respectively. Four subtypes of Blastocystis spp. were detected: ST5 (n = 6), ST10 (n = 50), ST14 (n = 14), and ST21 (n = 6). Among them, ST10 was the dominant genotype, accounting for 65.79% of strains, followed by the genotypes ST14 (18.42%), zoonotic ST5 (7.89%), and ST21 (7.89%). Four genotypes of E. bieneusi were detected: CHG3 (n = 32), CM21 (n = 4), CHG1 (n = 2), and ET-L2 (n = 2). Among these, CHG3 was the dominant genotype. Assemblage E (n = 54) and concurrent assemblages A and E (n = 2) were identified in the G. duodenalis-positive goats using multilocus genotyping. Blastocystis spp., E. bieneusi, and G. duodenalis infections were common in Leizhou black goats, all of which have zoonotic genotypes, indicating the potential risk of zoonotic transmission. Our results provide basic data for the prevention and control of these three intestinal pathogens. Further studies are required to better understand their genetic characteristics and zoonotic potential in Guangdong Province.

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.

Molecular detection and prevalence of human-pathologic Enterocytozoon bieneusi among pet birds in Mosul, Iraq

Enterocytozoon bieneusi has been classified as an emerging infectious organism (microsporidium) due to the global increase in the number of cases infecting both humans and animals. The goal of this study was to use the polymerase chain reaction method to determine the prevalence and risk factors associated with E. bieneusi infection among pet birds in Mosul, Iraq. Faecal samples from a total of six hundred and twenty-eight pet birds belonging to fifteen (15) different species were analyzed by targeting the internal transcribed spacer (ITS) of the rRNA gene. Of the total number of pet birds sampled, 203 tested positive for the parasite, representing 32.32% (95% CI = 28.75-36.06) of the sampled population. There was a significant difference (p < 0.01) in the prevalence of E. bieneusi infection among the different species of pet birds, with the highest prevalence recorded among Eurasian bullfinches (Pyrrhula pyrrhula) (64.06%; 95% CI = 55.48-72.02), budgerigars (Melopsittacus undulatus) (48.72%; 95% CI = 40.93-56.55), Fischer's lovebirds (Agapornis fischeri) (25.00%; 95% CI = 13.45-40.05), and macaws parrots (Ara ararauna) (25.00%; 95% CI = 1.25-75.77). The order, source, and health status of pet birds were significantly (p < 0.05) associated with the prevalence of E. bieneusi infection among pet birds in Mosul, Iraq. In conclusion, the level of prevalence of E. bieneusi among pet birds may increase the risk of infection for owners of pet birds in Iraq.

Endoparasites Infecting Domestic Animals and Spectacled Bears (Tremarctos ornatus) in the Rural High Mountains of Colombia

Simple Summary

The spectacled bear (Tremarctos ornatus) is a threatened species, a member of the Ursidae family that lives in the Andes rural high mountain territories of Colombia, Venezuela, Ecuador, Peru, and Bolivia near livestock areas. Parasites in the spectacled bear are a relevant area of interest to preserve this species and understand its habitats and interactions with farm animals. The present work aimed to evaluate the presence of endoparasites in both T. ornatus and domestic animals in these areas, by copro- parasitological examination. The results indicate that some parasites have zoonotic potential in wild endangered species and domestic animals in Colombian regions. More sensitive molecular techniques are needed for further identification of the parasite species.

Abstract

This research described the co-infection prevalence of endoparasites in Tremartus ornatus and domestic animals in the rural high mountains of Colombia by copro-parasitological examination. Some parasites have a zoonotic potential in wild endangered species and domestic animals in Colombian regions. T. ornatus had a notable infection with Eimeria spp., Ascaris spp., Ancylostoma spp., and Baylisascaris spp. Cryptosporidium spp., Balantidium coli, Anoplocephala spp., and Acanthamoeba spp. In B. taurus, Eimeria spp. is coinfecting with Cryptosporidium spp. (6.6%) and represents 18% of the total parasitism. In E. caballus and B. taurus. Eimeria spp. coinfecting (34.7%), with the Strongylus spp. (21.9–25%). In T. ornatus, Eimeria spp. is coinfecting with Ancylostoma spp. (36.2%), Cryptosporidium spp., Ascaris spp., Baylisascaris spp., and B. coli.

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.

Molecular Detection and Genotyping of Enterocytozoon bieneusi in Black Goats (Capra hircus) in Yunnan Province, Southwestern China

Simple Summary

Enterocytozoon bieneusi is one of the most common parasites in human and animals, and a threat to public health. So far, no data are available for E. bieneusi prevalence and genotypes in black goats in Yunnan Province, Southwestern China. Therefore, the objective of this study was to detect the prevalence and genotypes of E. bieneusi by examining 907 fecal samples collected from 5 counties in Yunnan Province. Ninety-three fecal samples (10.3%) were E. bieneusi-positive by PCR amplification. Four new genotypes and 11 known genotypes were identified, and all genotypes considered to be the zoonotic potential. Phylogenetic analysis showed that all of these genotypes were allocated into the zoonotic groups of E. bieneusi indicating its zoonotic potential. These results indicated that effective strategies and measures must be taken to prevent and control E. bieneusi transmission to other animals and humans.

Abstract

Enterocytozoon bieneusi is a fungus-like protist that can parasitize in the intestines of humans and various animals causing a threat to public health. However, there has been no data for E. bieneusi prevalence and genotypes in black goats in Yunnan Province, Southwestern China. In this study, 907 fecal samples were collected from black goats in 5 counties from Yunnan Province. The prevalence and genotypes of E. bieneusi were examined by nested PCR amplification targeting the nuclear internal transcribed spacer (ITS). Multi-locus sequence typing (MLST) was used to further examine the potential occurrence of genetic segregation. The overall prevalence of E. bieneusi in black goats in Yunnan Province was 10.3% (93/907). Statistical analysis revealed that E. bieneusi prevalence was significantly associated with the region, age and gender of black goats (p < 0.001). Four new genotypes (CYG-1, CYG-2, CYG-3, CYG-4) and 11 known genotypes (CHG1, CHG2, CHG3, CHG5, CHG28, J, D, BEB6, Wildboar3, CD6, SDD1) of E. bieneusi were identified. At the microsatellite and minisatellite loci, 15, 2, 17, and 33 sequences were obtained, respectively, forming one new multi-locus genotype (MLG27). Phylogenetic analysis revealed that all 15 genotypes were clustered into group 1 and group 2, with zoonotic potential. This is the first report of E. bieneusi prevalence and genotypes in black goats in Yunnan Province, China. Effective control strategies and measures should be taken to reduce the risk of E. bieneusi transmission between black goats, other animals, and humans.

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.

The global molecular epidemiology of microsporidia infection in sheep and goats with focus on Enterocytozoon bieneusi: a systematic review and meta-analysis

BACKGROUND

Microsporidia is a zoonotic pathogen with health consequences in immunocompromised patients. Small ruminants are a potential reservoir of microsporidia for humans in their vicinity. Hence, we aimed to evaluate the molecular prevalence of microsporidian infections with emphasis on Enterocytozoon bieneusi genotypes among sheep and goats at a global scale through systematic review and meta-analysis approach.

METHODS

The standard protocol of preferred reporting items for systematic reviews and meta-analyses (PRISMA) guidelines were followed. Eligible prevalence studies on small ruminant microsporidiosis, published from 1 January 2000 until 15 April 2021 were gathered using systematic literature search in PubMed, Scopus, Web of Science and Google Scholar databases. Inclusion and exclusion criteria were applied. The point estimates and 95% confidence intervals were calculated using a random-effects model. The variance between studies (heterogeneity) was quantified by I² index.

RESULTS

In total, 25 articles (including 34 datasets) were included for final meta-analysis. The pooled molecular prevalence of microsporidia in sheep and goats was estimated to be 17.4% (95% CI: 11.8-25%) and 16% (95% CI: 11.2-22.4%), respectively. Likewise, the overall prevalence of E. bieneusi was estimated to be 17.4% (95% CI: 11.8-25%) for sheep and 16.3% (95% CI: 11.3-22.8%) for goats. According to internal transcribed spacer (ITS) gene analysis, E. bieneusi with genotypes BEB6 (15 studies) and COS-1 (nine studies) in sheep, and CHG3 (six studies) and BEB6 (five studies) in goats were the highest reported genotypes.

CONCLUSION

The present results highlight the role of sheep and goats as reservoir hosts for human-infecting microsporidia. Therefore, this global estimate could be beneficial on preventive and control measures.

Molecular detection of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in school children at the Thai-Myanmar border

Few data are available on the genetic identity of enteric protists Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in humans in Thailand. In this study, 254 stool samples were collected from primary school children from Ratchaburi Province at the Thai-Myanmar border and examined for Cryptosporidium spp., G. duodenalis, E. bieneusi and Cyclospora cayetanensis using PCR techniques. The genotype identity of the pathogens was determined by DNA sequence analysis of the PCR products. Cryptosporidium felis was found in 1 stool sample, G. duodenalis in 19 stool samples, and E. bieneusi in 4 stool samples. For G. duodenalis, sub-assemblage AII was the dominant genotype, but one infection with assemblage F was found. The E. bieneusi genotypes found included known genotypes D and J, and one novel genotype (HPTM1). Cyclospora cayetanensis was not detected in any samples. Results of the preliminary study indicate that children at the Thai-Myanmar border from Ratchaburi Province, Thailand are infected with diverse zoonotic genotypes of Cryptosporidium spp., G. duodenalis, and E. bieneusi.

First molecular characterization of Enterocytozoon bieneusi in children and calves in Bangladesh

Enterocytozoon bieneusi is a widespread opportunistic pathogen found in humans and domestic animals, including cattle that poses a public health risk. This study was performed to evaluate the prevalence, genotypic diversity, and zoonotic potential of E. bieneusi among children and calves in Bangladesh. A total of 998 fecal samples were collected from children (n = 299) and calves (n = 699) and screened by nested PCR and sequencing of the ribosomal internal transcribed spacer (ITS). The overall prevalence of E. bieneusi infection was 6.4% in children and 7.9% in calves. ITS sequence analysis of 74 isolates revealed 10 genotypes, including eight known genotypes (A, D, Type IV, PigEBITS7, I, J, BEB4, and BEB6) and two new genotypes (BANEB1 and BANEB3). Specifically, genotypes A, D, Type IV, PigEBITS7, BANEB1, and BANEB3, and genotypes D, PigEBITS7, I, J, BEB4, and BEB6 were detected in children and calves, respectively. Among them, genotypes D and I were dominant genotypes in children and calves, respectively. The genotypes D and PigEBITS7 were found in both children and calves, with PigEBITS7 being observed for the first time in calves. In phylogenetic analysis, six genotypes (A, D, Type IV, PigEBITS7, BANEB1, and BANEB3), detected in 39.2% of the isolates, belonged to zoonotic Group 1. The remaining four genotypes I, J, BEB4, and BEB6 were clustered in Group 2 and are common members of the group with zoonotic potential. To the best of our knowledge, this study provides the first report of E. bieneusi infection in calves in Bangladesh and also the first molecular characterization of the parasite in children and calves in this country. Two new genotypes in children have been found, which is noteworthy. Furthermore, the presence of zoonotic genotypes indicates that cattle may serve as reservoirs for E. bieneusi, which can be a source of human microsporidiosis.

The largest meta-analysis on the global prevalence of microsporidia in mammals, avian and water provides insights into the epidemic features of these ubiquitous pathogens

Background

Microsporidia are obligate intracellular parasites that can infect nearly all invertebrates and vertebrates, posing a threat to public health and causing large economic losses to animal industries such as those of honeybees, silkworms and shrimp. However, the global epidemiology of these pathogens is far from illuminated.

Methods

Publications on microsporidian infections were obtained from PubMed, Science Direct and Web of Science and filtered according to the Newcastle-Ottawa Quality Assessment Scale. Infection data about pathogens, hosts, geography and sampling dates were manually retrieved from the publications and screened for high quality. Prevalence rates and risk factors for different pathogens and hosts were analyzed by conducting a meta-analysis. The geographic distribution and seasonal prevalence of microsporidian infections were drawn and summarized according to sampling locations and date, respectively.

Results

Altogether, 287 out of 4129 publications up to 31 January 2020 were obtained and met the requirements, from which 385 epidemiological data records were retrieved and effective. The overall prevalence rates in humans, pigs, dogs, cats, cattle, sheep, nonhuman primates and fowl were 10.2% [2429/30,354; 95% confidence interval (CI) 9.2–11.2%], 39.3% (2709/5105; 95% CI 28.5–50.1%), 8.8% (228/2890; 95% CI 5.1–10.1%), 8.1% (112/1226; 95% CI 5.5–10.8%), 16.6% (2216/12,175; 95% CI 13.5–19.8%), 24.9% (1142/5967; 95% CI 18.6–31.1%), 18.5% (1388/7009; 95% CI 13.1–23.8%) and 7.8% (725/9243; 95% CI 6.4–9.2%), respectively. The higher prevalence in pigs suggests that routine detection of microsporidia in animals should be given more attention, considering their potential roles in zoonotic disease. The highest rate was detected in water, 58.5% (869/1351; 95% CI 41.6–75.5%), indicating that water is an important source of infections. Univariate regression analysis showed that CD4+ T cell counts and the living environment are significant risk factors for humans and nonhuman primates, respectively. Geographically, microsporidia have been widely found in 92 countries, among which Northern Europe and South Africa have the highest prevalence. In terms of seasonality, the most prevalent taxa, Enterocytozoon bieneusi and Encephalitozoon, display different prevalence trends, but no significant difference between seasons was observed. In addition to having a high prevalence, microsporidia are extremely divergent because 728 genotypes have been identified in 7 species. Although less investigated, microsporidia coinfections are more common with human immunodeficiency virus and Cryptosporidium than with other pathogens.

Conclusions

This study provides the largest-scale meta-analysis to date on microsporidia prevalence in mammals, birds and water worldwide. The results suggest that microsporidia are highly divergent, widespread and prevalent in some animals and water and should be further investigated to better understand their epidemic features.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13071-021-04700-x.

Genotyping and zoonotic potential of Enterocytozoon bieneusi in cattle farmed in Hainan Province, the southernmost region of China

Enterocytozoon bieneusi is an intestinal pathogen that infects a wide range of species, including humans. Cattle constitute an important host for E. bieneusi; however, there is a scarcity of information on the prevalence and genotyping of E. bieneusi in cattle in the Hainan Province of China. In this study, PCR analysis of 314 fecal samples from cattle in six cities of Hainan was performed for genotype identification. The average prevalence of E. bieneusi in these animals was 9.9% (31/314), and ranged from 0.0% (0/12) to 20.5% (8/39). Five known genotypes – EbpC (n = 14), BEB4 (n = 12), J (n = 2), I (n = 1), and CHG5 (n = 1) – and a novel genotype: HNC-I (n = 1) – were identified. Genotypes EbpC and HNC-I were placed in zoonotic Group 1, and the remaining four genotypes (BEB4, J, I, and CHG5) were placed in Group 2. Since 93.5% of the genotypes found in the cattle (29/31) (EbpC, BEB4, J, and I) have previously been found in humans, these genotypes are probably involved in the transmission of microsporidiosis to humans.

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.

Enterocytozoon bieneusi in raw milk of cattle, sheep and water buffalo in Turkey: Genotype distributions and zoonotic concerns

Raw milk is a continued threat to public health due to possible contamination with zoonotic pathogens. Enterocytozoon bieneusi is one of the most prevalent pathogenic fungi in a wide range of vertebrate hosts, causing diarrheal disease. Although there has been some evidence, the role and potential risk of raw milk of dairy animals in the transmission dynamics of E. bieneusi is not clear. Therefore, we aimed to determine the occurrence and genotypes of E. bieneusi in raw milk of dairy animals in several farms of the Central Anatolia Region. We also investigated if there is a relation between the presence of E. bieneusi and mastitis. Genomic DNAs from a total of 450 raw milk including 200, 200 and 50 samples from cattle, sheep and water buffalo respectively were analyzed using nested PCR, targeting the internal transcribed spacer of E. bieneusi. Totally milk samples of 9 (4.5%) dairy cattle, 36 (18.0%) sheep, and 1 (2.0%) water buffalo were PCR-positive. A significant relationship was determined between mastitis and the presence of E. bieneusi. Sequence analysis revealed the presence of eight genotypes: two known (ERUSS1, BEB6) and six novel genotypes (named as TREb1 to TREb6). The genotype ERUSS1 and BEB6 were the most common genotypes, found in all cattle and sheep farms. Phylogenetic analysis clustered all the identified genotypes in Group 2. This study provides novel findings that contribute to the transmission dynamics and molecular epidemiology of E. bieneusi. Our study also highlighted the potential risk of raw milk for public health with respect to microsporidia infections.

Innate and Adaptive Immune Responses Against Microsporidia Infection in Mammals

Microsporidia are obligate intracellular and eukaryotic pathogens that can infect immunocompromised and immunocompetent mammals, including humans. Both innate and adaptive immune systems play important roles against microsporidian infection. The innate immune system can partially eliminate the infection by immune cells, such as gamma delta T cell, natural killer cells (NKs), macrophages and dendritic cells (DCs), and present the pathogens to lymphocytes. The innate immune cells can also prime and enhance the adaptive immune response via surface molecules and secreted cytokines. The adaptive immune system is critical to eliminate microsporidian infection by activating cytotoxic T lymphocyte (CTL) and humoral immune responses, and feedback regulation of the innate immune mechanism. In this review, we will discuss the cellular and molecular responses and functions of innate and adaptive immune systems against microsporidian infection.

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.

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.

Genotypes and zoonotic potential of Enterocytozoon bieneusi in edible bullfrogs (Lithobates catesbeiana) in China

Enterocytozoon bieneusi, an obligate intracellular pathogen of the intestinal epithelium, is commonly identified in humans and many other animals and is ubiquitous in water sources and the environment generally. To determine the molecular prevalence of E. bieneusi in edible bullfrogs (Lithobates catesbeiana) and evaluate the possibility of its potential zoonotic transmission to humans via food or water, the intestinal contents of 295 bullfrogs were intermittently collected from two open markets in Aksu, China. The samples were screened for the internal transcribed spacer by polymerase chain reaction amplifications, revealing that 20.7% (61/295) of them were infected with E. bieneusi, with no significant differences found between the two sampling locations (p > 0.05). Twenty-two different E. bieneusi genotypes were identified, including one known genotype (EbpC) and 19 novel ones (named BLC1 to BLC19). The zoonotic genotype EbpC was identified in most of the E. bieneusi-positive samples (65.6%, 40/61). The remaining genotypes were identified in either one or three samples each. Our phylogenetic analysis showed that 20 of the E. bieneusi genotypes belonged to Group 1. As far as we are aware, this is the first report of E. bieneusi infections in edible bullfrogs. Our findings suggest that E. bieneusi can be maintained in edible bullfrogs and potentially transmitted via food or water. It is possible that these amphibians are unsuspected zoonotic reservoirs of E. bieneusi.

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First report of Enterocytozoon bieneusi infections in edible bullfrogs.

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Overall detection ratio of E. bieneusi was 20.7% in edible bullfrogs.

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Zoonotic genotype EbpC was the predominant genotype.

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All the identified twenty E. bieneusi genotypes belonged to zoonotic group 1.

PCR-Based Detection of Cryptosporidium spp. and Enterocytozoon bieneusi in Farm-Raised and Free-Ranging Geese (Anser anser f. domestica) From Hainan Province of China: Natural Infection Rate and the Species or Genotype Distribution

Cryptosporidium spp. and Enterocytozoon bieneusi are two important zoonotic pathogens that can infect humans and a broad range of animal hosts. However, few studies have been conducted to study infection of the two pathogens in domestic geese until now. The aims of the present study were to determine the prevalence of natural infection, and the species or genotype distribution of Cryptosporidium and E. bieneusi in farm-raised and free-ranging geese from Hainan Province of China. In total, 266 fecal samples of geese were collected (142 farm-raised and 124 free-ranging geese). Cryptosporidium spp. and E. bieneusi were identified by nested PCR and sequencing analysis of the SSU rRNA and the ITS region of the rRNA genes. A total of 4.1% (12/226) of the geese were positive for Cryptosporidium spp., with 0.7% identified in the farm-raised geese and 7.0% in the free-ranging geese. Two bird-adapted species/genotypes were identified: C. baileyi (n = 1) and Cryptosporidium goose genotype I (n = 11). Meanwhile, E. bieneusi was found in 13.9% (37/266) of geese, with 8.9% identified in the farm-raised and 21.8% in the free-ranging geese. Eleven genotypes of E. bieneusi were identified constituted with six known genotypes: D (n = 13), I (n = 5), CHG2 (n = 1), CHG3 (n = 5), and CHG5 (n = 1), and five novel genotypes named HNE-I to V (one each). All of the genotypes identified in the geese here belonged to zoonotic Groups 1 or 2. This study is the first to demonstrate the presence of Cryptosporidium spp. and E. bieneusi in domestic geese from Hainan, China, and provides baseline data that will be useful for controlling and preventing these pathogens in goose farms. The geese infected with E. bieneusi, but not with Cryptosporidium, should be considered potential public health threats.

Genotype identification and phylogenetic analysis of Enterocytozoon bieneusi in farmed black goats (Capra hircus) from China's Hainan Province

Enterocytozoon bieneusi is an important pathogen commonly found in humans and animals. Farmed animals with close contact to humans are important hosts of E. bieneusi. The role of goats in the transmission of E. bieneusi, however, remains unclear. In this study, 341 fresh fecal samples of black goats were collected from five locations in Hainan Province, China. Enterocytozoon bieneusi was identified and genotyped by sequences of the internal transcribed spacer (ITS) region. Phylogenetic analysis was performed by constructing a neighbor-joining tree of the ITS gene sequences. The average prevalence of E. bieneusi in black goats was 24.0% (82/341) with rates ranging from 6.3% (4/63) to 37.2% (32/86) across the locations (χ² = 17.252, p < 0.01). Eight genotypes of E. bieneusi were identified, including six known genotypes: CHG5 (n = 47); CHG3 (n = 23); CHG2 (n = 4); CM21 (n = 3); D (n = 2); and AHG1 (n = 1), and two novel genotypes termed HNG-I (n = 1) and HNG-II (n = 1). In the phylogenetic tree, genotype D was clustered into Group 1 and the other identified genotypes were included in Group 2. This represents the first report identifying E. bieneusi in black goats from Hainan Province, with a high prevalence and wide occurrence demonstrated. The two new genotypes identified provide additional insights into the genotypic variations in E. bieneusi. Due to the small percentage of zoonotic genotypes in these animals, there is minimal risk of zoonotic transmission of E. bieneusi.