Zoonotic potential of Enterocytozoon bieneusi in pre-weaned Korean native calves

Prevalence and Molecular Characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in Cattle in Heilongjiang Province, Northeast China

Crytosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are important diarrheal pathogens with a global distribution that threatens the health of humans and animals. Despite cattle being potential transmission hosts of these protozoans, the associated risks to public health have been neglected. In the present study, a total of 1155 cattle fecal samples were collected from 13 administrative regions of Heilongjiang Province. The prevalence of Cryptosporidium spp., G. duodenalis, and E. bieneusi were 5.5% (64/1155; 95% CI: 4.2-6.9), 3.8% (44/1155; 95% CI: 2.7-4.9), and 6.5% (75/1155; 95% CI: 5.1-7.9), respectively. Among these positive fecal samples, five Cryptosporidium species (C. andersoni, C. bovis, C. ryanae, C. parvum, and C. occultus), two G. duodenalis assemblages (E and A), and eight E. bieneusi genotypes (BEB4, BEB6, BEB8, J, I, CHS7, CHS8, and COS-I) were identified. Phylogenetic analysis showed that all eight genotypes of E. bieneusi identified in the present study belonged to group 2. It is worth noting that some species/genotypes of these intestinal protozoans are zoonotic, suggesting a risk of zoonotic disease transmission in endemic areas. The findings expanded our understanding of the genetic composition and zoonotic potential of Cryptosporidium spp., G. duodenalis, and E. bieneusi in cattle in Heilongjiang Province.

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.

Prevalence and Molecular Characterization of Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi in Diarrheic and Non-Diarrheic Calves from Ningxia, Northwestern China

Cryptosporidium spp., Giardia duodenalis, and Enterocytozoon bieneusi are significant parasitic gastrointestinal pathogens with global distribution in humans and domestic animals, including calves. The main symptoms of calf infection are severe diarrhea, dehydration, growth retardation, and sometimes even death. To date, there has been limited information on the prevalence of Cryptosporidium spp., G. duodenalis, and E. bieneusi infections in calves in Ningxia, China, especially between diarrheic and non-diarrheic calves. A total of 438 fecal samples were collected from diarrheic (201) and non-diarrheic (237) calves in Ningxia. PCR and DNA sequencing were used to find the prevalence of Cryptosporidium spp. at 46.8% (205/438), G. duodenalis at 16.9% (74/438), and E. bieneusi at 10.0% (44/438). The prevalence of Cryptosporidium spp. infection in diarrheic and non-diarrheic calves was 54.0% (128/237) and 38.3% (77/201), respectively, and statistical analysis showed a positive correlation between the prevalence of Cryptosporidium spp. infection and calf diarrhea (p < 0.01). However, in this study, there was no statistical correlation between the prevalence of G. duodenalis infection as well as E. bieneusi infection and calf diarrhea (p > 0.05). Furthermore, four known Cryptosporidium species were successfully identified by comparing them with SSU rRNA gene sequences, including C. parvum, C. bovis, C. ryanae, and C. andersoni. In addition, all 74 G. duodenalis-positive samples were identified as assemblage E by comparative analysis of bg gene sequences. Among the 44 E. bieneusi-positive samples sequenced in the present study, 4 distinct E. bieneusi genotypes were successfully identified by comparative analysis of ITS sequences, including 3 known genotypes (J, BEB4, and N) and 1 novel genotype, the latter of which was identified and designated as NX1. These findings indicated that the high genetic diversity and complex population structures of Cryptosporidium spp., G. duodenalis, and E. bieneusi in Ningxia diarrhea calves and non-diarrhea calves, which provide new data for understanding the epidemiological status of Cryptosporidium spp., G. duodenalis, and E. bieneusi in Ningxia calves.

Enterocytozoon bieneusi in fecal samples from calves and cows in Austria

Enterocytozoon bieneusi is an obligate intracellular pathogen that infects livestock, companion animals, and wildlife and has the potential to cause severe diarrhea especially in immunocompromised humans. In the underlying study, fecal samples from 177 calves with diarrhea and 174 adult cows originating from 70 and 18 farms, respectively, in Austria were examined for the presence of E. bieneusi by polymerase chain reaction targeting the Internal Transcribed Spacer 1 (ITS1) region. All positive samples were further sequenced for genotype determination. Overall, sixteen of the 351 (4.6%) samples were positive for E. bieneusi, two of the 174 samples from cows (1.2%) and 14 of the 177 samples from calves (7.9%). In total, four genotypes, J (n = 2), I (n = 12), BEB4 (n = 3), and BEB8 (n = 1), were identified. The uncorrected p-distance between the four ITS1 lineages (344 bp) ranges from 0.3% to 2.9%. The lineages differ by 1 bp (I and J), 2 bp (J and BEB4), and 3 bp (I and BEB4), respectively, and BEB8 differs by 7 to 10 bp from the latter three lineages. Two of the E. bieneusi-positive calves showed an infection with two different genotypes. E. bieneusi occurred significantly more often in calves > 3 weeks (8/59) than in calves ≤ 3 weeks (6/118), respectively (p = 0.049). Calves with a known history of antimicrobial treatment (50 of 177 calves) shed E. bieneusi significantly more often than untreated calves (p = 0.012). There was no statistically significant difference in E. bieneusi shedding in calves with or without a medical history of antiparasitic treatment (p = 0.881). Calves showing a co-infection with Eimeria spp. shed E. bieneusi significantly more often than uninfected calves (p = 0.003). To our knowledge, this is the first report of E. bieneusi in cattle in Austria. Cattle should be considered as a reservoir for human infection since potentially zoonotic E. bieneusi genotypes were detected.

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.

Enterocytozoon bieneusi Genotypes and Infections in the Horses in Korea

Enterocytozoon bieneusi is a microsporidian pathogen. Recently, the equestrian population is increasing in Korea. The horse-related zoonotic pathogens, including E. bieneusi, are concerns of public health. A total of 1,200 horse fecal samples were collected from riding centers and breeding farms in Jeju Island and inland areas. Of the fecal samples 15 (1.3%) were PCR positive for E. bieneusi. Interestingly, all positive samples came from Jeju Island. Diarrhea and infection in foals were related. Two genotypes (horse1, horse2) were identified as possible zoonotic groups requiring continuous monitoring.

Prevalence and molecular characterization of Cryptosporidium spp. and Enterocytozoon bieneusi from large-scale cattle farms in Anhui Province, China

To investigate the prevalence of Cryptosporidium spp. and Enterocytozoon bieneusi from large-scale cattle farms in Anhui Province, 955 fecal samples were collected from 16 cattle farms from March to October 2018, which included six dairy farms (526), seven yellow cattle farms (323), and three water buffalo farms (106) in different regions of Anhui Province. PCR was conducted on all fecal samples using the 18S ribosomal RNA of Cryptosporidium spp. and internal transcribed spacer gene of E. bieneusi to detect these two pathogens, and the positive samples were sequenced and analyzed. The results showed that 23 (2.4%) and 40 (4.2%) out of the 955 samples were positive for Cryptosporidium spp. and E. bieneusi, respectively. There were 11 (2.1%), 10 (3.1%), and 2 (1.9%) positive samples of Cryptosporidium spp. and 16 (3.0%), 23 (7.1%), and 1 (0.9%) positive samples of E. bieneusi collected from dairy cattle, yellow cattle, and water buffalo, respectively, and no co-infection was identified in this study. All positive samples of Cryptosporidium spp. were C. andersoni with some variations. Ten E. bieneusi genotypes were obtained, including two known genotypes, J and CHN11, and eight new genotypes, named AHDC1 and AHYC1-7. The genotype CHN11 belonged to zoonotic Group 1, and the other nine genotypes belonged to Group 2, which is mainly documented in ruminants. These results indicated that Cryptosporidium spp. and E. bieneusi infections were present in large-scale cattle farms in Anhui Province. Therefore, attention should be paid to the development of containment strategies of these two pathogens in cattle.

First Identification and Genotyping of Enterocytozoon bieneusi and Prevalence of Encephalitozoon intestinalis in Patients with Acute Diarrhea in the Republic of Korea

Encephalitozoon intestinalis and Enterocytozoon bieneusi can cause diarrhea in humans, especially severe diarrhea in immunocompromised patients. However, there have been few studies on Enc. intestinalis and Ent. bieneusi in patients with acute diarrhea in the Republic of Korea (ROK). In this study, fecal samples were collected from 1241 patients with acute diarrhea in 2020. Among these, 24 cases of Enc. intestinalis and one case of Ent. bieneusi were detected via PCR amplification of small subunit ribosomal RNA. Genotyping of the internal transcribed spacer region sequence revealed that the detected Ent. bieneusi genotype was in Group 1. This study provides the first evidence that Ent. bieneusi exists in humans in addition to animals in the ROK. To identify the causative agent, continuous monitoring of Enc. intestinalis and Ent. bieneusi is necessary for patients with acute diarrhea in the ROK.

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

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

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

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

FIRST REPORT OF ENTEROCYTOZOON BIENEUSI FROM AN AFRICAN LION (PANTHERA LEO) IN A ZOO IN THE REPUBLIC OF KOREA

Enterocytozoon bieneusi is the most common species of microsporidia that infects humans and animals worldwide. However, no information is available on E. bieneusi infection among zoo animals in the Republic of Korea (ROK). Here, we investigated the prevalence of E. bieneusi among animals kept in zoos and the zoonotic potential of the E. bieneusi identified. E. bieneusi was detected only in one African lion (Panthera leo) with diarrhea, using PCR and sequencing analysis of the internal transcribed spacer (ITS) of the rRNA gene. A phylogenetic analysis based on the ITS gene showed that the lion isolate was classified into a novel genotype KPL belonging to Group 2. The KPL genotype identified in this study differed from genotype I in 6 nucleotides and from genotype I-like in 3 nucleotides, respectively, indicating that Group 2 has the capacity to infect a wide range of hosts. This is the first report of the presence of E. bieneusi in an African lion housed in a zoo in the ROK. Further investigation is necessary to study E. bieneusi infection among zoo animals in various regions and to determine the transmission route, in order to control E. bieneusi infection.