Detection and Genotyping of Enterocytozoon bieneusi in Pigeons

Prevalence and genotypic diversity of Enterocytozoon bieneusi in pigeons from two parks in Zhengzhou, China

Enterocytozoon bieneusi is a predominant pathogen that presents significant public health and animal husbandry challenges. Information on the prevalence and genotypes of E. bieneusi in pigeons is scarce. In this study, 207 faecal samples were collected from pigeons in two parks in Zhengzhou, China, and subjected to nested polymerase chain reaction (nested-PCR) analysis for the detection of E. bieneusi. The overall prevalence of E. bieneusi was found to be 15.5% (32/207) across the two parks. ITS sequence analysis identified only the Peru6 genotype (n = 32), which phylogenetic analysis placed within the zoonotic group 1. Among the E. bieneusi isolates, multilocus sequence typing (MLST) at MS1, MS4 and MS7 loci identified 19, 13 and 23 samples, respectively. Of the samples, 11 were successfully amplified and sequenced at all three loci, resulting in nine distinct multilocus genotypes (MLGs). This suggests that pigeons may play a role in the transmission of E. bieneusi to humans and that there is high genetic variability of E. bieneusi in pigeons from Zhengzhou in China.

Genetic diversity of Cryptosporidium spp., Encephalitozoon spp. and Enterocytozoon bieneusi in feral and captive pigeons in Central Europe

Cryptosporidium spp., Enterocytozoon bieneusi and Encephalitozoon spp. are the most common protistan parasites of vertebrates. The results show that pigeon populations in Central Europe are parasitised by different species of Cryptosporidium and genotypes of microsporidia of the genera Enterocytozoon and Encephalitozoon. A total of 634 and 306 faecal samples of captive and feral pigeons (Columba livia f. domestica) from 44 locations in the Czech Republic, Slovakia and Poland were analysed for the presence of parasites by microscopy and PCR/sequence analysis of small subunit ribosomal RNA (18S rDNA), 60 kDa glycoprotein (gp60) and internal transcribed spacer (ITS) of SSU rDNA. Phylogenetic analyses revealed the presence of C. meleagridis, C. baileyi, C. parvum, C. andersoni, C. muris, C. galli and C. ornithophilus, E. hellem genotype 1A and 2B, E. cuniculi genotype I and II and E. bieneusi genotype Peru 6, CHN-F1, D, Peru 8, Type IV, ZY37, E, CHN4, SCF2 and WR4. Captive pigeons were significantly more frequently parasitised with screened parasite than feral pigeons. Cryptosporidium meleagridis IIIa and a new subtype IIIl have been described, the oocysts of which are not infectious to immunodeficient mice, whereas chickens are susceptible. This investigation demonstrates that pigeons can be hosts to numerous species, genotypes and subtypes of the studied parasites. Consequently, they represent a potential source of infection for both livestock and humans.

High Prevalence of Microsporidia in the North African Hedgehog (Atelerix algirus) in the Canary Islands, Spain

Microsporidia are unicellular eukaryotic obligate intracellular parasites with a wide range of hosts reported worldwide; however, little is known about the epidemiological data on microsporidia infection in animals from the Canary Islands. Since data on microsporidia infection in hedgehog species are scarce, the aim of this study was to analyze the presence and identity of microsporidia in a group of North African hedgehogs (Atelerix algirus) using microscopic and molecular methods. From December 2020 to September 2021, a total of 36 fecal samples were collected from naturally deceased hedgehogs from Tenerife and Gran Canaria. All samples showed spore-compatible structures (100%; 36/36) under microscopic analysis, of which 61.1% (22/36) were amplified via the nested-polymerase chain reaction (PCR) targeting the partial sequence of the 16S rRNA gene, the internal transcribed spacer (ITS) region, and the partial sequence of the 5.8S rRNA gene. After Sanger sequencing and ITS analysis, Enterocytozoon bieneusi was detected in 47.2% (17/36) of the samples, identifying two novel genotypes (AAE1 and AAE2), followed by the detection of an undetermined species in 8.3% (3/36) and Encephalitozoon cuniculi genotype I in 5.6% (2/36) of the samples. This study constitutes the first report of microsporidia species in Atelerix algirus worldwide, highlighting the high prevalence of zoonotic species.

Zoonotic Enterocytozoon bieneusi genotypes in free-ranging and farmed wild ungulates in Spain

Microsporidia comprises a diverse group of obligate, intracellular, and spore-forming parasites that infect a wide range of animals. Among them, Enterocytozoon bieneusi is the most frequently reported species in humans and other mammals and birds. Data on the epidemiology of E. bieneusi in wildlife is limited. Hence, E. bieneusi was investigated in eight wild ungulate species present in Spain (genera Ammotragus, Capra, Capreolus, Cervus, Dama, Ovis, Rupicapra, and Sus) by molecular methods. Faecal samples were collected from free-ranging (n = 1058) and farmed (n = 324) wild ungulates from five Spanish bioregions. The parasite was detected only in red deer (10.4%, 68/653) and wild boar (0.8%, 3/359). Enterocytozoon bieneusi infections were more common in farmed (19.4%, 63/324) than in wild (1.5%, 5/329) red deer. Eleven genotypes were identified in red deer, eight known (BEB6, BEB17, EbCar2, HLJD-V, MWC_d1, S5, Type IV, and Wildboar3) and three novel (DeerSpEb1, DeerSpEb2, and DeerSpEb3) genotypes. Mixed genotype infections were detected in 15.9% of farmed red deer. Two genotypes were identified in wild boar, a known (Wildboar3) and a novel (WildboarSpEb1) genotypes. All genotypes identified belonged to E. bieneusi zoonotic Groups 1 and 2. This study provides the most comprehensive epidemiological study of E. bieneusi in Spanish ungulates to date, representing the first evidence of the parasite in wild red deer populations worldwide. Spanish wild boars and red deer are reservoir of zoonotic genotypes of E. bieneusi and might play an underestimated role in the transmission of this microsporidian species to humans and other animals.

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

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

Molecular Detection and 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.

Survey on the Presence of Bacterial and Parasitic Zoonotic Agents in the Feces of Wild Birds

Wild avifauna may act as fecal source of bacterial and parasitic pathogens for other birds and mammals. Most of these pathogens have a relevant impact on human and livestock health which may cause severe disease and economic loss. In the present study, the fecal samples collected from 121 wild birds belonging to 15 species of the genera Anas, Tadorna, Fulica, Arddea, Larus, Falco, Athene, Accipiter, and Columba were submitted to bacteriological and molecular analyses to detect Brucella spp., Coxiella burnetii, Mycobacterium spp., Salmonella spp., Cryptosporidium spp., Giardia spp., and microsporidia. Four (3.3%) animals were positive for one pathogen: one Anas penelope for C. burnetii, one Larus michahellis for S. enterica serovar Coeln, and two Columba livia for Encephalitozoon hellem. Although the prevalence rates found in the present survey were quite low, the obtained results confirm that wild birds would be the a potential fecal source of bacterial and parasitic zoonotic pathogens which sometimes can also represent a severe threat for farm animals.

First report and molecular prevalence of potential zoonotic Enterocytozoon bieneusi in Turkish tumbler pigeons (Columba livia domestica)

A total of 250 droppings of tumbler pigeons (Columba livia domestica, Columbidae) were collected individually from different breeders in Turkey, to investigate the presence and genotyping of microsporidian species by nested PCR and to reveal their zoonotic potential. In the present study, Enterocytozoon bieneusi was the only microsporidian species identified in 35 pigeons with an overall molecular prevalence of 14.0%. Only one known genotype zoonotic Peru6 was identified in all positive samples according to the sequence analyses of the internal transcribed spacer region of ribosomal DNA of E. bieneusi. This study represents the first report of E. bieneusi in pigeons in Turkey. Our study also confirms the competence of breeding pigeons as hosts for the zoonotic Peru6 genotype, corroborating its potential role as a source of human infection and environmental contamination.

LAY SUMMARY

Microsporidia are spore-producing fungi defined as emerging opportunistic pathogens of humans. The occurrence of microsporidia in animals could be risky for human public health. Home kept breeding pigeons pose a high risk for transmission of the microsporidians to humans.

Enterocytozoon bieneusi of animals-With an 'Australian twist'

Enterocytozoon bieneusi is a microsporidian microorganism that causes intestinal disease in animals including humans. E. bieneusi is an obligate intracellular pathogen, typically causing severe or chronic diarrhoea, malabsorption and/or wasting. Currently, E. bieneusi is recognised as a fungus, although its exact classification remains contentious. The transmission of E. bieneusi can occur from person to person and/or animals to people. Transmission is usually via the faecal-oral route through E. bieneusi spore-contaminated water, environment or food, or direct contact with infected individuals. Enterocytozoon bieneusi genotypes are usually identified and classified by PCR-based sequencing of the internal transcribed spacer region (ITS) of nuclear ribosomal DNA. To date, ~600 distinct genotypes of E. bieneusi have been recorded in ~170 species of animals, including various orders of mammals and reptiles as well as insects in >40 countries. Moreover, E. bieneusi has also been found in recreational water, irrigation water, and treated raw- and waste-waters. Although many studies have been conducted on the epidemiology of E. bieneusi, prevalence surveys of animals and humans are scant in some countries, such as Australia, and transmission routes of individual genotypes and related risk factors are poorly understood. This article/chapter reviews aspects of the taxonomy, biology and epidemiology of E. bieneusi; the diagnosis, treatment and prevention of microsporidiosis; critically appraises the naming system for E. bieneusi genotypes as well as the phylogenetic relationships of these genotypes; provides new insights into the prevalence and genetic composition of E. bieneusi populations in animals in parts of Australia using molecular epidemiological tools; and proposes some areas for future research in the E. bieneusi/microsporidiosis field.

Molecular detection and genotyping of microsporidia species in chickens in Turkey

Microsporidia are obligate intracellular pathogens that infect various hosts including invertebrates and vertebrates. Despite the importance, knowledge on the prevalence and molecular characteristics of microsporidia in chickens is limited, and no data are available for Turkey. A total of 300 fecal samples from chickens in the Central Anatolia Region of Turkey were analyzed by using a nested polymerase chain reaction assay targeting the rRNA internal transcribed spacer (ITS) region for the common microsporidia species. Corresponding PCR amplicons from the positive samples were sequenced for genotyping. Enterocytozoon bieneusi was identified in 22 (7.3 %) samples, whereas Encephalitozoon spp. was not detected. The prevalence of E. bieneusi was 63.6 % in Kayseri and 36.4 % in Nevsehir provinces, and 8.8 % in soft fecal samples and 9.7 % in diarrhoeic samples. No infections were found in Kirsehir Province. Significant differences were found for the distribution of E. bieneusi among provinces and fecal conditions. Infections were found only in free-range chickens. As a result of ITS region sequencing, two genotypes were characterized. The novel genotype ERUNT1 (n = 21), belonging to zoonotic group 1, was the most common genotype throughout the study area. The other known genotype, ERUSS1 (n = 1), had a restricted distribution and was previously detected in cattle and sheep in the same region. Our study provides the first data on microsporidia species from chickens in Turkey. None of these genotypes have been reported in humans; thus, the risk potential for public health is limited but needs further investigation.

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.

Occurrence and genetic diversity of Enterocytozoon bieneusi (Microsporidia) in owned and sheltered dogs and cats in Northern Spain

Enterocytozoon bieneusi is an obligate intracellular protist-like fungi parasite that infects numerous mammal hosts including humans, raising concerns of zoonotic transmission. There is little information available on the presence and diversity of E. bieneusi genotypes in companion animals. Here, we determined the occurrence and genetic diversity of E. bieneusi in domestic dogs and cats from Northern Spain. A total of 336 genomic DNA samples extracted from canine (n = 237) and feline (n = 99) faecal specimens were retrospectively investigated. The presence of E. bieneusi was assessed by PCR of the rRNA internal transcribed spacer (ITS) gene. The parasite was detected in 3.0% (3/99) and 0.8% (2/237) of the cats and dogs examined, respectively. All three feline positive samples were from stray cats living in an urban setting, whereas the two canine samples were from owned dogs living in rural areas. Sequence analysis revealed the presence of two genotypes in dogs, BEB6 and PtEb IX, and two genotypes in cats, D and Peru11. The identification of Peru11 in a cat and BEB6 in a dog constitutes the first report of those genotypes in such hosts as well as first report in Spain. This is also the first evidence of genotype D in cats and PtEb IX in dogs in Spain. Three out of the four genotypes, BEB6, D and Peru11, have been previously reported as human pathogens and are potentially zoonotic indicating that dogs and cats need to be considered potential sources of human infection and environmental contamination.

New genotypes and molecular characterization of Enterocytozoon bieneusi in pet birds in Southwestern China

Enterocytozoon bieneusi, a unicellular enteric microsporidian parasite, can infect humans and a wide range of animals throughout the world. Although E. bieneusi has been identified in many animals, there is no information regarding the genotypes of E. bieneusi in pet birds in China. Birds are important sources of emerging infectious diseases that affect humans, and immunosuppressed individuals can be exposed to potential zoonotic agents shed by birds. The aim of the present study was to determine the prevalence and genotypic diversity of E. bieneusi in pet birds, as well as assessed its zoonotic potential. A total of 387 fecal samples were collected from Psittaciformes (n = 295), Passeriformes (n = 67), and Galliformes (n = 16) from four pet markets in Sichuan province, Southwestern China. The overall prevalence of E. bieneusi in pet birds was 25.1% based on nested polymerase chain reaction analysis of the internal transcribed spacer (ITS) region of the ribosomal RNA (rRNA) gene (Psittaciformes, 21.7%; Passeriformes, 37.3%; Galliformes, 50.0%). Eight genotypes of E. bieneusi were identified, including five known genotypes (D, SC02, BEB6, CHB1, and MJ5) and three novel genotypes (SCB-I, SCB-II, and SCB-III). In phylogenetic analysis, genotypes D and SC02 and one novel genotype SCB-II were clustered within group 1, genotype BEB6 was classified within group 2, and the remaining genotypes (CHB1, MJ5, SCB-I, and SCB-III) clustered with group 10. To the best of our knowledge, this is the first report of E. bieneusi infection in pet birds in China. Genotypes D, SC02, and BEB6 that have been previously identified in humans, were found in pet birds in this study, suggesting that these pet birds can be a potential source of human microsporidiosis in China.

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This is the first to report the prevalence of E. bieneusi in pet birds in China.

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The overall prevalence of E. bieneusi was 25.1% (97/387) based on PCR analysis of the ITS region of the ribosomal RNA gene.

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Five known genotypes (D, SC02, BEB6, CHB1, and MJ5) and three novel genotypes (SCB-I, SCB-II, and SCB-III) were identified.

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This study will enrich the epidemiological data of E. bieneusi infection in China.

Molecular Characterization of Enterocytozoon bieneusi in Wild Carnivores in Spain

Microsporidia comprises a diverse group of obligate intracellular parasites that infect a broad range of invertebrates and vertebrates. Among Microsporidia, Enterocytozoon bieneusi is the most frequently detected species in humans and animals worldwide bringing into question the possible role of animal reservoirs in the epidemiology of this pathogen. Although E. bieneusi is an emerging zoonotic pathogen able to infect many domestic and wild mammals that could act as reservoir of infection for humans and other animals, only few studies have documented its occurrence in wild carnivores. To determine the occurrence of E. bieneusi in wild carnivores, we examined 190 wild carnivores collected from different locations in Spain. Twenty-five fecal samples (13.2%) from three host species (European badger, beech marten, and red fox) were E. bieneusi-positive by PCR. Nucleotide sequence analysis of the ITS region revealed a high degree of genetic diversity with a total of eight distinct genotypes including four known (PtEbIX, S5, S9, and WildBoar3) and four novel (EbCar1-EbCar4) genotypes identified. Phylogenetic analysis showed that the four novel genotypes (EbCar1-EbCar4), S5, S9, and WildBoar3 clustered within the previously designated zoonotic Group 1. Our results demonstrate that human-pathogenic genotypes are present in wild carnivores, corroborating their potential role as a source of human infection and environmental contamination.

Molecular diagnosis of potentially human pathogenic Enterocytozoon bieneusi and Encephalitozoon species in exotic birds in Southwestern Iran

Microsporidia are obligate intracellular parasites that produce spores. The infections caused by these parasites are mostly considered to be opportunistic in immunodeficient patients. Because of the zoonotic nature of microsporidia as well as the increasing prevalence of immunodeficiency diseases, the aim of this study was to evaluate the molecular diagnosis of Enterocytozoon bieneusi (E. bieneusi) and Encephalitozoon spp. in exotic birds in southwestern Iran. Initially, 816 stool specimens were collected and stained by modified trichrome (Weber) staining. The slides were explored using light microscopy. In the next stage, the extracted DNA was amplified using a multiplex/nested PCR method. RFLP with the Mnl1 restriction enzyme was used to differentiate the Encephalitozoon species in the products of the molecular analysis. Out of 816 samples, 138 and 181 cases were found to be positive by the staining and the multiplex/nested-PCR methods, respectively. Of the 181 samples, 103 and 78 samples were positive for E. bieneusi and Encephalitozoon spp., respectively. The Encephalitozoon species were 17 E. cuniculi, 52 E. intestinalis and 9 E. hellem. Of 103 E. bieneusi samples, 57, 39, 2 and 5 cases were detected as genotypes D, M, E and L, respectively. The results showed a relatively high prevalence of microsporidia in exotic birds, and according to the results of the genotyping, these birds can be an important source of microsporidiosis. It is essential that high-risk individuals, including patients with immunodeficiency diseases, receive accurate and valid information about the risk of direct and indirect contact with infected exotic birds.

Survey for Zoonotic Microsporidian Pathogens in Wild Living Urban Rooks (Corvus frugilegus)

Microsporidia are opportunistic pathogens in nature infecting all animal phyla. There is a potential risk of microsporidian spores transmission from urban rooks inhabiting some metropolitan cities to people through casual interactions. The aim of this study was to identify microsporidia species in the droppings of rooks in Wroclaw, Poland. A total of 15 collective sets of droppings were examined using nested-PCR method. Amplification of ITS rRNA gene revealed the presence of Enterocytozoon bieneusi D, Peru 6, and Encephalitozoon hellem 1A genotypes. This study indicates that excreta of urban rooks can be an important source of human infection with these pathogens.

Molecular identification of Enterocytozoon bieneusi, Cryptosporidium, and Giardia in Brazilian captive birds

A total of 85 fecal samples from captive birds collected from October 2013 to September 2014 in Uberlândia and Belo Horizonte in the state of Minas Gerais (Brazil) were evaluated for the presence of Enterocytozoon bieneusi, Cryptosporidium, and Giardia by PCR. Of these, three birds were found positive for E. bieneusi (3.5%), two for Cryptosporidium (2.3%), and one for Giardia (1.2%). Two genotypes of E. bieneusi were detected by nucleotide sequence analysis of the ITS region, genotypes D and Peru 6 in a swan goose and in two rock pigeons, respectively. For Cryptosporidium and Giardia, nucleotide sequence analysis of the SSU rRNA identified Cryptosporidium baileyi and Duck genotype in a swan goose and a mandarin duck, respectively, and Giardia duodenalis assemblage A in a toco toucon. Our results demonstrate that human-pathogenic E. bieneusi genotypes D and Peru6 and G. duodenalis assemblage A are present in captive birds in Brazil, corroborating their potential role as a source of human infection and environmental contamination.

More than a rabbit's tale - Encephalitozoon spp. in wild mammals and birds

Within the microsporidian genus Encephalitozoon, three species, Encephalitozoon cuniculi, Encephalitozoon hellem and Encephalitozoon intestinalis have been described. Several orders of the Class Aves (Passeriformes, Psittaciformes, Apodiformes, Ciconiiformis, Gruiformes, Columbiformes, Suliformes, Podicipediformes, Anseriformes, Struthioniformes, Falconiformes) and of the Class Mammalia (Rodentia, Lagomorpha, Primates, Artyodactyla, Soricomorpha, Chiroptera, Carnivora) can become infected. Especially E. cuniculi has a very broad host range while E. hellem is mainly distributed amongst birds. E. intestinalis has so far been detected only sporadically in wild animals. Although genotyping allows the identification of strains with a certain host preference, recent studies have demonstrated that they have no strict host specificity. Accordingly, humans can become infected with any of the four strains of E. cuniculi as well as with E. hellem or E. intestinalis, the latter being the most common. Especially, but not exclusively, immunocompromised people are at risk. Environmental contamination with as well as direct transmission of Encephalitozoon is therefore highly relevant for public health. Moreover, endangered species might be threatened by the spread of pathogens into their habitats. In captivity, clinically overt and often fatal disease seems to occur frequently. In conclusion, Encephalitozoon appears to be common in wild warm-blooded animals and these hosts may present important reservoirs for environmental contamination and maintenance of the pathogens. Similar to domestic animals, asymptomatic infections seem to occur frequently but in captive wild animals severe disease has also been reported. Detailed investigations into the epidemiology and clinical relevance of these microsporidia will permit a full appraisal of their role as pathogens.

Genotyping of Enterocytozoon bieneusi (Microsporidia) isolated from various birds in China

Enterocytozoon bieneusi is a common opportunistic pathogen causing diarrhea in humans and animals. However, epidemiological data on E. bieneusi infections in birds are relatively scare worldwide, especially in China. To understand the prevalence and genetic diversity of E. bieneusi in birds and to assess the zoonotic potential of bird-derived E. bieneusi isolates, 194 fecal specimens from Gruidae, Anatidae and Columbidae in Heilongjiang Province, China, were analyzed by PCR and sequencing of the single internal transcribed spacer region of the rRNA gene. The average prevalence of E. bieneusi was 22.2%, with 12.5% for Gruidae, 15.9% for Anatidae and 44.0% for Columbidae. Altogether seven genotypes of E. bieneusi were identified, including four known genotypes-Peru6 (n=29), BEB6 (n=5), D (n=3) and EbpA (n=1)-and three novel genotypes named CHN-B1 (n=1), CHN-B2 (n=3) and CHN-B3 (n=1). All the known genotypes obtained here were previously detected in humans. All the novel genotypes were clustered into the zoonotic group 1 in phylogenetic analysis. The results indicate that these birds may play a potential role in the transmission of E. bieneusi to humans.

Widespread presence of human-pathogenic Enterocytozoon bieneusi genotypes in chickens

A total of 151 fecal specimens from chickens were randomly collected from local markets in Uberlândia and Belo Horizonte in the state of Minas Gerais, Brazil, to evaluate the presence of Enterocytozoon bieneusi by polymerase chain reaction (PCR). Enterocytozoon bieneusi was identified in 24 fecal samples (15.9%). This represents the first report of E. bieneusi in chickens in Brazil. All PCR-positive specimens were sequenced and 4 genotypes were identified, Peru 6, Peru 11, Type IV, and D. All four genotypes have previously been reported as human pathogens and are potentially zoonotic. Our results demonstrate that human-pathogenic E. bieneusi genotypes are present in chickens in Brazil, corroborating their potential role as a source of human infection and environmental contamination.

Culture and propagation of microsporidia of veterinary interest

Microsporidia are obligate intracellular mitochrondria-lacking pathogens that rely on host cells to grow and multiply. Microsporidia, currently classified as fungi, are ubiquitous in nature and are found worldwide. They infect a large number of mammals and are recognized as opportunistic infection agents in HIV-AIDS patients. Its importance for veterinary medicine has been unveiled in recent years through the description of clinical and subclinical forms of infection in domestic and wild animals. Domestic and wild birds may be infected by the same human microsporidia, reinforcing their zoonotic potential. Microsporidiosis in fish is prevalent and causes significant economic losses for fish farming. Some species of microsporidia have been propagated in cell cultures, which may provide conditions for the development of diagnostic techniques, understanding of pathogenesis and immune responses and for the discovery of potential therapies. Unfortunately, the cultivation of these parasites is not fully standardized in most research laboratories, especially in the veterinary field. The aim of this review is to relate the most important microsporidia of veterinary interest and demonstrate how these pathogens can be grown and propagated in cell culture for diagnostic purposes or for pathogenesis studies. Cultivation of microsporidia allowed the study of its life cycle, metabolism, pathogenesis and diagnosis, and may also serve as a repository for these pathogens for molecular, biochemical, antigenic and epidemiological studies.

Microsporidia detection and genotyping study of human pathogenic E. bieneusi in animals from Spain

Microsporidia are ubiquitous parasites infecting all animal phyla and we present evidence that supports their zoonotic potential. Fecal samples taken from domestic (cats and dogs), farm (pigs, rabbits and ostriches) and wild animals (foxes) from different provinces of Spain were evaluated for microsporidia infection by light microscopy and PCR. After Microsporidia species identification, E. bieneusi genotypes were additionally studied by sequence analysis of the ITS region. Eighty-five samples out of 159 exhibited structures that were compatible with microsporidia spores by Webeŕs stain with 37 of them being confirmed by PCR. Microsporidia species identified included E. bieneusi, E. intestinalis and A. algerae. We report the first diagnosis of E. intestinalis and E. bieneusi in ostriches and A. algerae in pigs. We also provide new information on the molecular characterization of E. bieneusi isolates both in rabbits and ostriches. All of the E. bieneusi genotypes identified belonged to the zoonotic group of genotypes (Group I) including genotypes A (dogs), I (pigs), D (rabbits and foxes) and type IV (ostriches). Our results demonstrate that microsporidia are present in domestic, farm and wild animals in Spain, corroborating their potential role as a source of human infection and environmental contamination.

Variability in minimal genomes: analysis of tandem repeats in the microsporidia Encephalitozoon intestinalis

Microsporidia are ubiquitous fungi with genomes that have undergone a strong reduction to the extreme cases of Encephalitozoon cuniculi and Encephalitozoon intestinalis. Genetic variability within species of the Encephalitozoon genus has been reported, with most of the studies based on the internal transcribed spacer (ITS) of the rDNA. However, in contrast to the picture of E. cuniculi and Encephalitozoon hellem, where different strains have been identified, no genetic variability has yet been observed in E. intestinalis. We have analysed tandem repeats included in putative coding sequences which could be used as polymorphic markers in E. intestinalis. Eight candidate loci (M2, M2A, M3, M5, M7, M7A, M8 and PTP1) were established and 9 E. intestinalis cultured strains from North America, South America and Europe were analysed. M2, M7 and PTP1 nucleotide sequences were identical among the different strains and the GenBank sequence. In contrast, we observed variants in 4 markers (M2A, M3, M7A and M8) which did not correspond to their respective reference sequences. The most noticeable finding was that with the M5 marker two genotypes were defined among the different strains studied, demonstrating genotypic variability of E. intestinalis. Although the diversity described is certainly not high, which can be explained by a lower chance of genetic variability in its minimal genome, we have demonstrated that polymorphisms actually exist in E. intestinalis. Epidemiological studies using this genetic marker should now be conducted to elucidate the genetic variability in E. intestinalis and improve our knowledge of the epidemiology of this microsporidia.

Encephalitozoon and Enterocytozoon (Microsporidia) spores in stool from pigeons and exotic birds: microsporidia spores in birds

Microsporidia are considered to be a cause of emerging and opportunistic infections in humans, and the species that infect humans can also infect a wide range of animals, raising concerns for zoonotic transmission. To understand the role of birds in the transmission of diseases caused by microsporidia, we examined 196 fecal specimens from birds, including birds of the families Psittacidae, Emberizidae, Icteridae and Columbidae, using Gram-chromotrope stain and polymerase chain reaction (PCR). Of the 196 fecal samples surveyed, 48 (24.5%) tested positive for microsporidia. The prevalence of microsporidia infection was higher in pigeons (31.1%) than in other birds (18.8%). The species of microsporidia that were detected in the birds surveyed in this study included Encephalitozoon hellem (found in 16.3% of positive samples), Enterocytozoon bieneusi (5.6%), Encephalitozoon intestinalis (1.5%) and Encephalitozoon cuniculi (1%). All the internal transcribed spacer (ITS) sequence of the rRNA from the study samples matched (with 100% identity) their correlate reference genotypes in GenBank, which included E. hellem 1A (AF338367), E. hellem 3 (AF110328), E. cuniculi I (AF338410) and E. bieneusi EpbA (AF076040). No fecal sample contained more than one type of microsporidian species. This study implicates exotic birds and pigeons as potential sources of microsporidia infection for humans living in urban areas.

Identification and characterization of microsporidia from fecal samples of HIV-positive patients from Lagos, Nigeria

Background

Microsporidia are obligate intracellular parasites that infect a broad range of vertebrates and invertebrates. They have been increasingly recognized as human pathogens in AIDS patients, mainly associated with a life-threatening chronic diarrhea and systemic disease. However, to date the global epidemiology of human microsporidiosis is poorly understood, and recent data suggest that the incidence of these pathogens is much higher than previously reported and may represent a neglected etiological agent of more common diseases indeed in immunocompetent individuals. To contribute to the knowledge of microsporidia molecular epidemiology in HIV-positive patients in Nigeria, the authors tested stool samples proceeding from patients with and without diarrhea.

Methodology/Principal Findings

Stool samples from 193 HIV-positive patients with and without diarrhea (67 and 126 respectively) from Lagos (Nigeria) were investigated for the presence of microsporidia and Cryptosporidium using Weber’s Chromotrope-based stain, Kinyoun stain, IFAT and PCR. The Weber stain showed 45 fecal samples (23.3%) with characteristic microsporidia spores, and a significant association of microsporidia with diarrhea was observed (O.R.  = 18.2; CI: 95%). A similar result was obtained using Kinyoun stain, showing 44 (31,8%) positive samples with structures morphologically compatible with Cryptosporidium sp, 14 (31.8%) of them with infection mixed with microsporidia. The characterization of microsporidia species by IFAT and PCR allowed identification of Enterocytozoon bieneusi, Encephalitozoon intestinalis and E. cuniculi in 5, 2 and 1 samples respectively. The partial sequencing of the ITS region of the rRNA genes showed that the three isolates of E.bieneusi studied are included in Group I, one of which bears the genotype B.

Conclusions/Significance

To our knowledge, this is the first report of microsporidia characterization in fecal samples from HIV-positive patients from Lagos, Nigeria. These results focus attention on the need to include microsporidial diagnosis in the management of HIV/AIDS infection in Nigeria, at the very least when other more common pathogens have not been detected.

First detection and genotyping of Encephalitozoon cuniculi in a new host species, gyrfalcon (Falco rusticolus)

Recently, the pathogenic species of microsporidia of the genus Encephalitozoon have been detected increasingly, also in representatives of the Aves class. Our study presents laboratory proof of Encephalitozoon cuniculi (E. cuniculi) genotype II in a new host, gyrfalcon (Falco rusticolus), with suspect microsporidiosis. E. cuniculi is an obligate intracellular microsporidian parasite that infects a wide range of mammalian hosts, including humans. Characterization of the internal transcribed spacer of the rRNA gene has identified three genotypes of E. cuniculi based on the number of 5'-GTTT-3' repeats present: a genotype I from rabbits and mice, containing three repeats; a genotype II from mice and dogs, containing two repeats; and a genotype III from dogs and fox, containing four repeats. Samples of faeces from 30 gyrfalcons were examined for the presence of microsporidia spores, using microscopical, molecular methods and sequencing. Microscopic analysis showed presence of brightly fluorescing oval shapes of size 1.5 × 3 μm, characteristic of the strain Microsporidia in five samples. The PCR method, using species non-specific (530F/580R) and species-specific (ECUNR/ECUNF) primers, proved the presence of E. cuniculi spores in two samples. After sequencing were confirmed, E. cuniculi genotype II which implies new host species for this parasite.

Microsporidia in exotic birds: intermittent spore excretion of Encephalitozoon spp. in naturally infected budgerigars (Melopsittacus undulatus)

Nine naturally infected asymptomatic budgerigars (Melopsittacus undulatus) were screened daily for microsporidia spore excretion during a 30-day period and the localization of infection was evaluated using microscopy and molecular methods. While the microscopic examination revealed 2.4% positivity out of all fecal samples, using PCR the positivity was 10x higher (24.6%). All nine budgerigars excreted microsporidial spores intermittently in irregular intervals with 1-11-day long interruptions. Most of the birds were infected simultaneously with Encephalitozoon cuniculi and Encephalitozoon hellem. While histological and TEM examination failed to confirm the presence of microsporidial spores in tissues, the PCR detected microsporidial DNA mostly in the small intestine, liver and lungs of four selected budgerigars dissected. Despite the chronic infection proved using molecular methods, no clinical signs of disease were observed during monitoring and no pathological findings were found during dissection.

Identification of Encephalitozoon cuniculi genotype III and two novel genotypes of Enterocytozoon bieneusi in swine

Samples of intestinal content from thirty fattened pigs of six farms slaughtered at an abattoir in North-Western Germany, and faecal samples of four pigs kept as laboratory animals at the Federal Institute for Risk Assessment (BfR, Berlin, Germany) were investigated for the occurrence of microsporidia by light microscopy, PCR and sequencing. A modified Webers trichrome staining and the immunohistochemistry (the Avidin-Biotin-Peroxidase-Complex technique with a polyclonal anti-Encephalitozoon cuniculi-serum and monoclonal antibodies against Encephalitozoon intestinalis and Enterocytozoon bieneusi) was used as a screening method for the light microscopical detection of these pathogenic eukaryotes. By this light microscopically methods microsporidia suspected organisms were found in all samples (100%). By the use of PCR, microsporidia were identified in fourteen samples (41.2%). The prevalence of microsporidia infections among the farms diversifies from 0 to 80% as considered by PCR. E. bieneusi was the most prevalent species and was identified in twelve fattened pigs (40%) from five of the six tested farms (83.3%) and in two of the four laboratory animals (50%). Three of the E. bieneusi species belonged to the genotype O, one to the genotype E, and one to the genotype F. Two isolates were identified as novel genotypes and two samples showed a mixed infection of different genotypes. In three faecal samples of the pigs from two farms E. cuniculi genotype III was identified. One sample contained both microsporidia species. To our knowledge, this is the first time that the genotype III of E. cuniculi was identified in swine.

The role of free-ranging, captive, and domestic birds of Western Poland in environmental contamination with Cryptosporidium parvum oocysts and Giardia lamblia cysts

As Cryptosporidium parvum and Giardia lamblia can be disseminated in the environment by avian hosts, a total of 499 fecal dropping from 308 free-ranging, 90 captive, and 101 domestic birds were tested by conventional, immunological, and molecular techniques for these human enteropathogens. Twenty-six (5.2%) tested positive for G. lamblia cysts and 19 (3.8%) for C. parvum oocysts. A bird total of 23 (7.5%) free-ranging, two (2.2%) captive, and one (0.1%) domestic tested positive for cysts, whereas 18 (5.8%) free-ranging, one (1.1%) captive, and zero livestock birds tested positive for oocysts. G. lamblia cysts and C. parvum oocysts were found significantly more frequently in fecal droppings of free-ranging aquatic birds than in birds not normally associated with water. No specimen tested positive for both pathogens simultaneously. Aquatic birds represent an important epidemiologic link in water-associated transmission cycles of Cryptosporidium and Giardia and play a significant role in environmental contamination of aquatic habitats with these anthropozoonotic pathogens.

The role of birds in dissemination of human waterborne enteropathogens

Cryptosporidiosis, giardiasis and microsporidiosis are serious human diseases of waterborne origin; their etiologic agents and a substantial fecal coliform load can enter surface, drinking and recreational water resources from aquatic birds. The aim of this article is to present interactions between waterfowl and these waters that imply a negative public health impact, reinforcing the need for either better water-quality indicators or for water monitoring specifically for Cryptosporidium, Giardia and microsporidia. Where justifiable, the presence of waterfowl should be supported; however, management of drinking and recreational water resources needs to be improved by incorporating effective protection measures for pathogens linked to these birds.

Urban feral pigeons (Columba livia) as a source for air- and waterborne contamination with Enterocytozoon bieneusi spores

This study demonstrated that a person with 30 min of occupational or nonoccupational exposure to urban feral pigeons, such as exposure through the cleaning of surfaces contaminated with pigeon excrement, could inhale approximately 3.5 x 10(3) Enterocytozoon bieneusi spores and that 1.3 x 10(3) spores could be inhaled by a nearby person.