Human Microsporidiosis Research Articles

Methionine aminopeptidases: Potential therapeutic target for microsporidia and other microbes.

Methionine aminopeptidases (MetAPs) have emerged as a target for medicinal chemists in the quest for novel therapeutic agents for treating cancer, obesity, and other disorders. Methionine aminopeptidase is a metalloenzyme with two structurally distinct forms in humans, MetAP-1 and MetAP-2. The MetAP2 inhibitor fumagillin, which was used as an amebicide in the 1950s, has been used for the successful treatment of microsporidiosis in humans; however, it is no longer commercially available. Despite significant efforts and investments by many pharmaceutical companies, no new MetAP inhibitors have been approved for the clinic. Several lead compounds have been designed and synthesized by researchers as potential inhibitors of MetAP and evaluated for their potential activity in a wide range of diseases. MetAP inhibitors such as fumagillin, TNP-470, beloranib, and reversible inhibitors and their analogs guide new prospects for MetAP inhibitor development in the ongoing quest for new pharmacological indications. This perspective provides insights into recent advances related to MetAP, as a potential therapeutic target in drug discovery, bioactive small molecule MetAP2 inhibitors, and data on the role of MetAP-2 as a therapeutic target for microsporidiosis.

Identification of common human infectious and potentially zoonotic novel genotypes of Enterocytozoon bieneusi in cavernicolous bats in Thailand.

Enterocytozoon bieneusi is a common cause of human microsporidiosis and can infect a variety of animal hosts worldwide. In Thailand, previous studies have shown that this parasite is common in domestic animals. However, information on the prevalence and genotypes of this parasite in other synanthropic wildlife, including bats, remains limited. Several pathogens have been previously detected in bats, suggesting that bats may serve as a reservoir for this parasite. In this study, a total of 105 bat guano samples were collected from six different sites throughout Thailand. Of these, 16 from Chonburi (eastern), Ratchaburi (western), and Chiang Rai (northern) provinces tested positive for E. bieneusi, representing an overall prevalence of 15.2%. Based on ITS1 sequence analysis, 12 genotypes were identified, including two known genotypes (D and type IV) frequently detected in humans and ten novel potentially zoonotic genotypes (TBAT01-TBAT10), all belonging to zoonotic group 1. Lyle's flying fox (Pteropus lylei), commonly found in Southeast Asia, was identified as the host in one sample that was also positive for E. bieneusi. Network analysis of E. bieneusi sequences detected in this study and those previously reported in Thailand also revealed intraspecific divergence and recent population expansion, possibly due to adaptive evolution associated with host range expansion. Our data revealed, for the first time, multiple E. bieneusi genotypes of zoonotic significance circulating in Thai bats and demonstrated that bat guano fertilizer may be a vehicle for disease transmission.

Design and evaluation of loop-mediated isothermal amplification for rapid detection of Enterocytozoon bieneusi

Enterocytozoon bieneusi is one of the most prevalent microsporidia species, responsible for more than 90% of human and animal microsporidiosis. Microsporidia species, particularly E. bieneusi, are frequently reported from waterborne and foodborne outbreaks. Therefore, early detection is crucial in clinics and outbreak investigations. This study aimed to design a loop-mediated isothermal amplification (LAMP) for rapid detection of E. bieneusi. Total DNA was extracted from 30 E. bieneusi –positive samples, which had been confirmed with nested PCR. LAMP primers were designed based on the identical fragment of small subunit ribosomal RNA (SSU rRNA) gene. LAMP reactions were performed at 63 °C for 60 min. The sensitivity and specificity of the assay were analyzed and the results of amplification were compared to real-time PCR. Our results showed that the LAMP assay successfully amplified 25/30 (83.3%) samples. The specificity results indicated no false positive with other microorganisms. Furthermore, the LAMP method exhibited a sensitivity (limit of detection, LoD) as low as 34 ag/μL of total DNA. Compared to the LAMP assay, real-time PCR was able to detect all 30 nested PCR-positive samples. Our findings showed that the LAMP assay was able to detect 83.3% of E. bieneusi-positive samples. Although the current assay was not able to detect all nested PCR-positive samples, the lack of need for specific instruments, rapid processes, and high specificity makes LAMP assay a suitable tool for screening.

Molecular detection of Enterocytozoon bieneusi in bats from Portugal.

Enterocytozoon bieneusi is a microsporidia commonly found in the gastrointestinal tract of humans and a wide range of other animals, constituting a major cause of microsporidiosis in humans. Although E. bieneusi has been detected in humans, domestic, and wild animals in Portugal, and its presence in bats has been linked to zoonotic characteristics, its occurrence in bats within the country has not been reported. In this study, we investigated the presence of E. bieneusi in 380 bat fecal samples collected in mainland Portugal through a nested PCR assay targeting the internal transcribed spacer region and the flanking small and large subunits of the ribosomal RNA. Enterocytozoon bieneusi was detected in one bat sample (i.e., 0.26%; Pipistrellus pipistrellus). Additionally, another sample tested positive for Enterocytozoon sp. Phylogenetic analysis of the obtained ITS sequence of E. bieneusi revealed clustering within the potentially zoonotic Group 1. This study represents the first report of E. bieneusi in a bat from Europe. Findings presented here contribute to an enhanced understanding of E. bieneusi epidemiology.

High genetic diversity of Enterocytozoon bieneusi in minks and raccoon dogs in northern China.

Enterocytozoon bieneusi, a zoonotic pathogen prevalent in both humans and animals, is the most frequently diagnosed microsporidian species in humans and presents significant public health risks. However, data on the prevalence and genotypes of E. bieneusi in farmed minks (Neovison vison) and raccoon dogs (Nyctereutes procyonoides) in China are limited. Therefore, 275 minks (89 from Hebei Province, 57 from Heilongjiang Province, 109 from Liaoning Province, 20 from Shandong Province) and 235 raccoon dogs (114 from Hebei Province, 27 from Heilongjiang Province, 61 from Liaoning Province, 33 from Jilin Province) were examined for the prevalence and genotypes of E. bieneusi through sequence analysis of the internal transcribed spacer (ITS) region of the rRNA gene. The overall prevalence of E. bieneusi was 18.6% (95/510), with 10.5% (29/275) in farmed minks and 28.1% (66/235) in raccoon dogs. Ten genotypes (CHN-F1, genotype D, Type IV, EbpC, NCF2, NCF5, NCF6, Peru8, Henan V, and MJ5) were identified in minks and raccoon dogs. This study is the first to detect the CHN-F1, NCF2, NCF6, Peru8, and Henan V genotypes in minks and the NCF5, NCF6, and MJ5 genotypes in raccoon dogs. Additionally, the D, Type IV, and Peru8 genotypes, previously identified in humans, were also found in minks and raccoon dogs, suggesting that these animals could be potential sources of human microsporidiosis. These findings expand the understanding of E. bieneusi's host distribution in China and contribute to the prevention of zoonotic E. bieneusi infections among farmed animals.

Microsporidia in HIV-Positive and HIV-Negative Pediatric Patients with Diarrhea at a Tertiary Care Hospital.

Background Human microsporidiosis presents as an important and rapidly emerging opportunistic infection. However, the exact burden of this infection especially in the pediatric population of Northern India remains unknown. In this study, we investigated the prevalence of microsporidia among human immunodeficiency virus (HIV)-positive and HIV-negative pediatric patients who presented with diarrhea. Methods A total of 263 children were recruited consisting of 98 HIV seropositive with diarrhea and 165 HIV seronegative but with diarrhea. Morning stool samples were collected and both direct and formol ether concentrated samples were examined for the presence of intestinal parasites. The modified acid-fast staining was done for coccidian parasites and trichrome stain for microsporidia detection. Further, the species were detected using a real-time polymerase chain reaction (PCR) targeting a conserved region of the small ribosomal subunit rRNA gene of Enterocytozoon bieneusi , Encephalitozoon hellem , Encephalitozoon intestinalis , and Encephalitozoon cuniculi . Results Overall, one or more parasites were detected in 52.04% (51/98) of HIV seropositive and 53.33% (88/165) of seronegative children ( p = 0.8391). However, coccidian parasites were detected in a significantly huge number of HIV seropositive children (21.43% [21/98]) as compared with HIV seronegative children (4.24% [7/165]). Microsporidial DNA could be detected in HIV seropositive with diarrhea children (17.35% [17/98]) by PCR. A significant correlation between low CD4 count (≤ 200/μL) and intestinal parasite positivity could be established. Conclusion Microsporidia is a significant cause of diarrhea in HIV seropositive pediatric patients and should be kept in mind as one of the differential diagnoses in such patients.

Human Microsporidiosis: A Narrative Review of Serodiagnostic Tests

Context: Microsporidiosis is an emerging disease in both immunocompetent and immunocompromised patients. Diagnosis of human microsporidiosis is challenging. Parasitological tests using staining methods have limitations for detecting spores in stool samples. The performance of molecular methods for diagnosing human microsporidiosis is satisfactory, but these methods are expensive and time-consuming. Serodiagnosis tests for the detection of antibodies have insufficient specificity. Detecting microsporidia antigens seems to be an appropriate method for diagnosing human microsporidiosis. Therefore, the present study reviewed serological approaches to assess the current status of these methods for diagnosing human microsporidiosis. Evidence Acquisition: All related published articles were searched. The search terms were “microsporidiosis”, “microsporidiasis”, “human microsporidiosis”, and “human microsporidiasis”, combined with the search terms “diagnosis”, “serodiagnosis”, “immunodiagnosis”, “antigen detection”, and “antibody detection”. Data were extracted from the articles that met our eligibility criteria. Immunodiagnosis studies in experimentally infected animals were excluded. Results: Few studies have evaluated the performance of serological tests for diagnosing human microsporidiosis. The IgG response against spore wall protein or polar tube antigens remains at least three years after infection and shows more cross-reactivity with other species. Therefore, the western blot should be conducted as a confirmatory method. Serodiagnosis tests using monoclonal antibodies against microsporidia showed less cross-reactivity and more efficacy compared to polyclonal antibodies. Conclusions: Indirect fluorescent antibody test based on the monoclonal antibody is highly effective in diagnosing microsporidia species in clinical samples.

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.

Global molecular epidemiology of microsporidia in pigs and wild boars with emphasis on Enterocytozoon bieneusi: A systematic review and meta-analysis.

BackgroundMicrosporidia are spore‐forming intracellular pathogens with worldwide prevalence, causing emerging infections in humans and animals. Enterocytozoon bieneusi is a zoonotic species of microsporidia and is responsible for more than 90% of cases of microsporidiosis in humans and animals. Pigs and wild boars are important animal reservoirs of microsporidia. Hence, we aimed to estimate the global prevalence of microsporidia and genetic diversity of E. bieneusi in pigs and wild boars through a set of systematic review and meta‐analysis (PRISMA) guidelines.MethodsFour databases (Web of Science, PubMed, Scopus and Google Scholar) were searched between January 1, 2000 and April 30, 2021. Regarding meta‐analysis, the random‐effect model was employed by forest plot with 95% confidence interval (CI).ResultsAfter exclusion of irrelevant articles and duplication removal, 33 papers, including 34 datasets (30 datasets for domestic pigs and 4 for wild boars) finally meet the inclusion criteria to undergo meta‐analysis. The pooled prevalence rates of microsporidia infection in domestic pigs and wild boars were 37.6% (95% CI: 30.8–44.9%) and 8.1% (95% CI: 2.1–26.8%), respectively. While, the pooled prevalence rates of E. bieneusi were 35% (95% CI: 28.4–42.2%) in domestic pigs and 10.1% (95% CI: 1.7–42.4%) in wild boars. The genotypes EbpA was the most reported genotype in domestic pigs and wild boars. Male animals had higher prevalence rates of microsporidia infection than females (27 vs. 17.4%, OR = 1.91; 95% CI, 0.77–4.71%).ConclusionThis study indicates the important role of domestic pigs and wild boars as animal reservoir hosts of microsporidia. Thereby, strategies for control and prevention of these zoonotic pathogens should be designed in pigs and wild boars.

Metabarcoding reveals low prevalence of microsporidian infections in castor bean tick (Ixodes ricinus)

BackgroundMicrosporidia is a large group of eukaryotic obligate intracellular spore-forming parasites, of which 17 species can cause microsporidiosis in humans. Most human-infecting microsporidians belong to the genera Enterocytozoon and Encephalitozoon. To date, only five microsporidian species, including Encephalitozoon-like, have been found in hard ticks (Ixodidae) using microscopic methods, but no sequence data are available for them. Furthermore, no widespread screening for microsporidian-infected ticks based on DNA analysis has been carried out to date. Thus, in this study, we applied a recently developed DNA metabarcoding method for efficient microsporidian DNA identification to assess the role of ticks as potential vectors of microsporidian species causing diseases in humans.MethodsIn total, 1070 (493 juvenile and 577 adult) unfed host-seeking Ixodes ricinus ticks collected at urban parks in the city of Poznan, Poland, and 94 engorged tick females fed on dogs and cats were screened for microsporidian DNA. Microsporidians were detected by PCR amplification and sequencing of the hypervariable V5 region of 18S rRNA gene (18S profiling) using the microsporidian-specific primer set. Tick species were identified morphologically and confirmed by amplification and sequencing of the shortened fragment of cytochrome c oxidase subunit I gene (mini-COI).ResultsAll collected ticks were unambiguously assigned to I. ricinus. Potentially zoonotic Encephalitozoon intestinalis was identified in three fed ticks (3.2%) collected from three different dogs. In eight unfed host-seeking ticks (0.8%), including three males (1.1%), two females (0.7%) and three nymphs (0.7%), the new microsporidian sequence representing a species belonging to the genus Endoreticulatus was identified.ConclusionsThe lack of zoonotic microsporidians in host-seeking ticks suggests that I. ricinus is not involved in transmission of human-infecting microsporidians. Moreover, a very low occurrence of the other microsporidian species in both fed and host-seeking ticks implies that mechanisms exist to defend ticks against infection with these parasites.Graphical abstract

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.

First detection and genotyping of Enterocytozoon bieneusi in pet golden hamsters (Mesocricetus auratus) and Siberian hamsters (Phodopus sungorus) in China.

Enterocytozoon bieneusi, a common opportunistic pathogen, has been detected in humans and a wide range of animals worldwide. However, no information on the prevalence and molecular characterization of E. bieneusi in hamsters is available worldwide. In this study, fecal specimens were collected from 175 golden hamsters and 175 Siberian hamsters purchased from pet shops in three provinces of China. The average infection rate of E. bieneusi was 12.0% (42/350), with 14.9% (26/175) in pet golden hamsters and 9.1% (16/175) in pet Siberian hamsters. Four genotypes were identified in pet golden hamsters, including three known genotypes (D, Henan-II, and SHW5) and one novel genotype (named Ebph1). Five genotypes were found in pet Siberian hamsters, including one known genotype (D) and four novel genotypes (named Ebph2 to Ebph5). Genotypes D and Ebph2 were the dominant genotype in pet golden hamsters (23/26, 88.5%) and Siberian hamsters (9/16, 56.3%), respectively. Phylogenetic analysis showed that the E. bieneusi isolates clustered into two groups: Group 1 (D, Henan-II, SHW5, and Ebph1) and Group 3 (Ebph2 to Ebph5). To the best of our knowledge, this is the first report of E. bieneusi infection in golden hamsters and Siberian hamsters worldwide. The identification of four genotypes belonging to Group 1 of high zoonotic potential suggests that pet hamsters especially golden hamsters can be potential sources of human microsporidiosis.

Enterocytozoon bieneusi

Enterocytozoon bieneusi is a microsporidium, related to Cryptomycota and fungi, which has been reported globally in a wide range of mammalian and avian hosts. It is responsible for over 90% of documented cases of human microsporidiosis and causes varying clinical symptoms, typically diarrhea and wasting. Infection begins with ingestion of spores in contaminated water and food. Spores deliver the infective sporoplasm into host enterocytes via the discharged polar tube. Meronts form and develop into multinucleated plasmodia, which undergo sporogony to form sporoblasts and then mature spores. Spores released from infected cells are shed with the stool. Sequence analysis of the ribosomal internal transcribed spacer (ITS) has identified over 500 genotypes, some of which are generalists of zoonotic importance and pose a threat to public health. Population genetic data uphold the zoonotic nature and host specificity of the parasite. Knowledge of its pathogenicity, immune responses, and expanded treatment options are urgently needed.

Microsporidiosis in Humans.

Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are about 220 genera and 1,700 species of microsporidia, which are classified based on their ultrastructural features, developmental cycle, host-parasite relationship, and molecular analysis. Phylogenetic analysis suggests that microsporidia are related to the fungi, being grouped with the Cryptomycota as a basal branch or sister group to the fungi. Microsporidia can be transmitted by food and water and are likely zoonotic, as they parasitize a wide range of invertebrate and vertebrate hosts. Infection in humans occurs in both immunocompetent and immunodeficient hosts, e.g., in patients with organ transplantation, patients with advanced human immunodeficiency virus (HIV) infection, and patients receiving immune modulatory therapy such as anti-tumor necrosis factor alpha antibody. Clusters of infections due to latent infection in transplanted organs have also been demonstrated. Gastrointestinal infection is the most common manifestation; however, microsporidia can infect virtually any organ system, and infection has resulted in keratitis, myositis, cholecystitis, sinusitis, and encephalitis. Both albendazole and fumagillin have efficacy for the treatment of various species of microsporidia; however, albendazole has limited efficacy for the treatment of Enterocytozoon bieneusi. In addition, immune restoration can lead to resolution of infection. While the prevalence rate of microsporidiosis in patients with AIDS has fallen in the United States, due to the widespread use of combination antiretroviral therapy (cART), infection continues to occur throughout the world and is still seen in the United States in the setting of cART if a low CD4 count persists.

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.

Molecular epidemiology of Microsporidia among HIV-positive and HIV-negative patients in the Limpopo province, South Africa.

Human microsporidiosis represents an important and rapidly emerging opportunistic disease. The present study investigated the prevalence of microsporidia among HIV positive and HIV negative patients with or without diarrhoea in Vhembe and Mopani Districts in the Limpopo Province. A total of 170 stool samples were collected from these patients and microsporidia species was detected using a Real-Time PCR targeting a conserved region of the small ribosomal subunit rRNA (SSU-rRNA) gene of Enterocytozoon bieneusi, Encephalitozoon intestinalis, Encephalitozoon hellem, and Encephalitozoon cuniculi. Fifty six (32.9%) were positive for microsporidia. The prevalence was higher in HIV negative patients (36.6%) while 24.1% of patients who were HIV positive had microsporidia. Microsporidia was more common among patients aged between 1 and 10 years (52.6%). However among the HIV positive patients, microsporidia prevalence was higher among those that were not taking antiretrovirals (ARVs) compared to those who were on ARVs, (36.6%) and (24.1%), respectively. Microsporidia was also noted to be significantly associated with diarrheal and stomach pains; p = 0.02 and p = 0.048, respectively. Furthermore, microsporidia infections was more prevalent among patients who had animals at home (p = 0.037). Study has shown a high prevalence of microsporidia among patients attending primary health centers in the Mopani District for the first time. Prevalence of microsporidia was higher among HIV negative and HIV positive patients who were not on ARV treatment. Keeping animals in the household appeared to be a risk of getting infected with microsporidia. Further studies are needed to determine the genetic characteristics of these organisms in the study population.

Prevalence and new genotypes of Enterocytozoon bieneusi in sheltered dogs and cats in Sichuan province, southwestern China.

Enterocytozoon bieneusi is a common intracellular parasite that infects a wide range of hosts, including humans and companion animals, raising concerns of zoonotic transmission. However, there is limited epidemiological information on the prevalence and genotypes of E. bieneusi in sheltered dogs and cats in Sichuan province, southwestern China. A total of 880 fecal samples were collected from shelters in different cities of Sichuan province, including 724 samples from dogs, and 156 samples from cats. Enterocytozoon bieneusi was determined by sequence analysis of the ribosomal internal transcribed spacer (ITS). Overall, the prevalence of E. bieneusi was 18% (158/880), and the parasite was detected in 18.8% (136/724) and 14.1% (22/156) of the dogs and cats examined, respectively. Sequence analysis revealed the presence of five genotypes in dogs, including three known genotypes CD9 (n = 92), PtEb IX (n = 41), and Type IV (n = 1), and two novel genotypes SCD-1 (n = 1) and SCD-2 (n = 1). Similarly, four genotypes were identified in cats, including CD9 (n = 11), Type IV (n = 6), D (n = 4), and PtEb IX (n = 1). Genotypes D and Type IV have previously been identified in humans and are reported in sheltered dogs and cats in the present study, indicating that these animals could be as potential sources of human microsporidiosis infections.

Epidemiological investigation and genotypes of Enterocytozoon bieneusi in 11 captive Rhesus macaque populations.

Enterocytozoon bieneusi is an obligate intracellular parasite and the most common pathogen of microsporidiosis in humans and animals. In this study, a total of 198 fecal samples were collected from 11 captive populations of Rhesus macaque in Chinese zoos, to investigate the prevalence and analyze the zoonotic potential of E. bieneusi by genotype of the Internal Transcribed Spacer (ITS) gene on the rRNA of E. bieneusi via nested PCR. Results showed that the average infection rate of E. bieneusi in the 11 populations was 13.6%, and the highest infection rate was 56.5% in the population of Xinjiang Tianshan Zoo. Seven genotypes were identified including 2 known genotypes (D and CM1) and 5 novel genotypes (Mul1, Mul2, Mul3, Mul4 and Mul5). Phylogenetic analysis revealed that the novel genotypes Mul2, Mul3, Mul4 and Mul5 belonged to Group 1 showed the zoonotic potential．These findings extend the distribution of E. bieneusi genotypes and provide baseline data for controlling E. bieneusi infection.

First identification and genotyping of Enterocytozoon bieneusi and Encephalitozoon spp. in pet rabbits in China

BackgroundMicrosporidia are common opportunistic parasites in humans and animals, including rabbits. However, only limited epidemiology data concern about the prevalence and molecular characterization of Enterocytozoon bieneusi and Encephalitozoon spp. in rabbits. This study is the first detection and genotyping of Microsporidia in pet rabbits in China.ResultsA total of 584 faecal specimens were collected from rabbits in pet shops from four cities in Sichuan province, China. The overall prevalence of microsporidia infection was 24.8% by nested PCR targeting the internal transcribed spacer (ITS) region of E. bieneusi and Encephalitozoon spp. respectively. E. bieneusi was the most common species (n = 90, 15.4%), followed by Encephalitozoon cuniculi (n = 34, 5.8%) and Encephalitozoon intestinalis (n = 16, 2.7%). Mixed infections (E. bieneusi and E. cuniculi) were detected in five another rabbits (0.9%). Statistically significant differences in the prevalence of microsporidia were observed among different cities (χ2 = 38.376, df = 3, P < 0.01) and the rabbits older than 1 year were more likely to harbour microsporidia infections (χ2 = 9.018, df = 2, P < 0.05). Eleven distinct genotypes of E. bieneusi were obtained, including five known (SC02, I, N, J, CHY1) and six novel genotypes (SCR01, SCR02, SCR04 to SCR07). SC02 was the most prevalent genotype in all tested cities (43.3%, 39/90). Phylogenetic analysis showed that these genotypes were clustered into group 1–3 and group 10. Meanwhile, two genotypes (I and II) were identified by sequence analysis of the ITS region of E. cuniculi.ConclusionTo the best of our knowledge, this is the first report of microsporidia infection in pet rabbits in China. Genotype SC02 and four novel genotypes were classified into potential zoonotic group 1, suggesting that pet rabbits may cause microsporidiosis in humans through zoonotic transmissions. These findings provide preliminary reference data for monitoring microsporidia infections in pet rabbits and humans.

Unusual dominant genotype NIA1 of Enterocytozoon bieneusi in children in Southern Xinjiang, China.

Enterocytozoon bieneusi is the mainly pathologies or intestinal disorders that causes approximately 90% of reported cases of human microsporidiosis. To understand the prevalence and genotype distribution of E. bieneusi in the Xinjiang Uygur Autonomous Region, China, 609 fecal samples were collected from children in kindergarten in Southern Xinjiang and screened for this pathogen by PCR and sequencing of the internal transcribed spacer (ITS). Thirty-six fecal samples (5.9%, 36/609) were positive for E. bieneusi, with the highest prevalence observed in children from Yopurga (17.5%, 11/63). Nine genotypes were identified, of which six were known (A, CHN6, D, EbpA, KB-1, and NIA1) and three were novel (CXJH1, CXJH2 and CXJH3). Genotype NIA1 was most prevalent (52.8%, 19/36), followed by genotypes D (16.7%, 6/36), A (8.3%, 3/36), and EbpA (8.3%, 3/36). The remaining five genotypes were detected in one sample each. Phylogenetic analysis revealed that the E. bieneusi isolates clustered into two groups, one consisting of six genotypes (Group 1: A, CXJH1, D, EbpA, KB-1, and NIA1) and another consisting of three genotypes (Group 2: CHN6, CXJH2, and CXJH3). Our results confirmed that infection of E. bieneusi unusual dominant genotype NIA1 occurs in children in Xinjiang, China. Further epidemiological studies must be conducted to clarify potential sources of E. bieneusi infection in this area.