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Clinical Microbiology Reviews Dec 2021Microsporidia are obligate intracellular pathogens identified ∼150 years ago as the cause of pébrine, an economically important infection in silkworms. There are...
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.
Topics: Gastrointestinal Diseases; Humans; Microsporidia; Microsporidiosis; Phylogeny; Prevalence
PubMed: 34190570
DOI: 10.1128/CMR.00010-20 -
Clinical Microbiology Reviews Oct 1994Microsporidia are obligate intracellular spore-forming protozoal parasites belonging to the phylum Microspora. Their host range is extensive, including most... (Review)
Review
Microsporidia are obligate intracellular spore-forming protozoal parasites belonging to the phylum Microspora. Their host range is extensive, including most invertebrates and all classes of vertebrates. More than 100 microsporidial genera and almost 1,000 species have now been identified. Five genera (Enterocytozoon spp., Encephalitozoon spp., Septata spp., Pleistophora sp., and Nosema spp.) and unclassified microsporidia (referred to by the collective term Microsporidium) have been associated with human disease, which appears to manifest primarily in immunocompromised persons. The clinical manifestations of microsporidiosis are diverse and include intestinal, pulmonary, ocular, muscular, and renal disease. Among persons not infected with human immunodeficiency virus, ten cases of microsporidiosis have been documented. In human immunodeficiency virus-infected patients, on the other hand, over 400 cases of microsporidiosis have been identified, the majority attributed to Enterocytozoon bieneusi, an important cause of chronic diarrhea and wasting. Diagnosis of microsporidiosis currently depends on morphological demonstration of the organisms themselves. Initial detection of microsporidia by light microscopic examination of tissue sections and of more readily obtainable specimens such as stool, duodenal aspirates, urine, sputum, nasal discharge, bronchoalveolar lavage fluid, and conjunctival smears is now becoming routine practice. Definitive species identification is made by using the specific fluorescein-tagged antibody (immunofluorescence) technique or electron microscopy. Treatment options are limited, but symptomatic improvement of Enterocytozoon bieneusi infection may be achieved with the anthelmintic-antiprotozoal drug albendazole. Preliminary observations suggest that Septata intestinalis and Encephalitozoon infections may be cured with albendazole. Progress is being made with respect to in vitro propagation of microsporidia, which is crucial for developing antimicrosporidial drugs. Furthermore, molecular techniques are being developed for diagnostic purposes, taxonomic classification, and analysis of phylogenetic relationships of microsporidia.
Topics: Animals; HIV Infections; Humans; Microscopy, Electron; Microscopy, Electron, Scanning; Microsporida; Microsporidiosis
PubMed: 7834600
DOI: 10.1128/CMR.7.4.426 -
BMC Veterinary Research Jun 2020Microsporidia are common opportunistic parasites in humans and animals, including rabbits. However, only limited epidemiology data concern about the prevalence and...
BACKGROUND
Microsporidia 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.
RESULTS
A 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 (χ = 38.376, df = 3, P < 0.01) and the rabbits older than 1 year were more likely to harbour microsporidia infections (χ = 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.
CONCLUSION
To 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.
Topics: Animals; China; Encephalitozoon; Enterocytozoon; Feces; Genotype; Microsporidiosis; Polymerase Chain Reaction; Prevalence; Rabbits
PubMed: 32571322
DOI: 10.1186/s12917-020-02434-z -
Journal of Fungi (Basel, Switzerland) Jul 2020Microsporidia are obligate intracellular pathogens that are currently considered to be most directly aligned with fungi. These fungal-related microbes cause infections... (Review)
Review
Microsporidia are obligate intracellular pathogens that are currently considered to be most directly aligned with fungi. These fungal-related microbes cause infections in every major group of animals, both vertebrate and invertebrate, and more recently, because of AIDS, they have been identified as significant opportunistic parasites in man. The Microsporidia are ubiquitous parasites in the animal kingdom but, until recently, they have maintained relative anonymity because of the specialized nature of pathology researchers. Diagnosis of microsporidia infection from stool examination is possible and has replaced biopsy as the initial diagnostic procedure in many laboratories. These staining techniques can be difficult, however, due to the small size of the spores. The specific identification of microsporidian species has classically depended on ultrastructural examination. With the cloning of the rRNA genes from the human pathogenic microsporidia it has been possible to apply polymerase chain reaction (PCR) techniques for the diagnosis of microsporidial infection at the species and genotype level. The absence of genetic techniques for manipulating microsporidia and their complicated diagnosis hampered research. This study should provide basic insights into the development of diagnostics and the pitfalls of molecular identification of these ubiquitous intracellular pathogens that can be integrated into studies aimed at treating or controlling microsporidiosis.
PubMed: 32707956
DOI: 10.3390/jof6030114 -
Pathogens (Basel, Switzerland) Aug 2022Microsporidia are a group of obligated intracellular fungus pathogens. Monocytes and the derivative macrophages are among the most important players in host immunity....
Microsporidia are a group of obligated intracellular fungus pathogens. Monocytes and the derivative macrophages are among the most important players in host immunity. The invasion of microsporidia may significantly affect the monocytes maturation and extravasation processes. We utilized a previously established microsporidia infection murine model to investigate the influences of microsporidia () infection on monocyte maturation, releasing into the circulation and extravasation to the inflammation site. Flow cytometry and qPCR analysis were used to compare the monocytes and derivative macrophages isolated from bone marrow, peripheral blood and tissues of -infected and control mice. The results showed that the pro-inflammatory group of CD11bLy-6C monocytes are promoted in -infected mice. Interestingly, the percentage of Ly-6C monocytes from -infected mice are significantly lower in peripheral blood while significantly higher in the inflamed small intestine, together with up-regulated ratio of F4/80 macrophage in small intestine as well. Our findings demonstrated that infection leads to promoted monocytes maturation in bone marrow, up-regulation of extravasation from peripheral blood to inflammation site and maturation into macrophages. Our study is the first systematic analysis of monocytes maturation and trafficking during microsporidia infection, and will provide better understanding of the pathogen-host interactions.
PubMed: 36015036
DOI: 10.3390/pathogens11080914 -
Emerging Infectious Diseases Mar 2022We identified Encephalitozoon cuniculi genotype II parasites as a cause of extraintestinal microsporidiosis in 2 owners of birds also infected with E. cuniculi. Patients...
We identified Encephalitozoon cuniculi genotype II parasites as a cause of extraintestinal microsporidiosis in 2 owners of birds also infected with E. cuniculi. Patients experienced long-lasting nonspecific symptoms; the disease course was more progressive in a patient with diabetes. Our findings suggest direct bird-to-human transmission of this pathogen.
Topics: Animals; Birds; Encephalitozoon cuniculi; Encephalitozoonosis; Genotype; Humans; Microsporidiosis
PubMed: 35202528
DOI: 10.3201/eid2803.211556 -
Clinical Microbiology Reviews Jul 2005Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic... (Review)
Review
Microsporidia are long-known parasitic organisms of almost every animal group, including invertebrates and vertebrates. Microsporidia emerged as important opportunistic pathogens in humans when AIDS became pandemic and, more recently, have also increasingly been detected in otherwise immunocompromised patients, including organ transplant recipients, and in immunocompetent persons with corneal infection or diarrhea. Two species causing rare infections in humans, Encephalitozoon cuniculi and Brachiola vesicularum, had previously been described from animal hosts (vertebrates and insects, respectively). However, several new microsporidial species, including Enterocytozoon bieneusi, the most prevalent human microsporidian causing human immunodeficiency virus-associated diarrhea, have been discovered in humans, raising the question of their natural origin. Vertebrate hosts are now identified for all four major microsporidial species infecting humans (E. bieneusi and the three Encephalitozoon spp.), implying a zoonotic nature of these parasites. Molecular studies have identified phenotypic and/or genetic variability within these species, indicating that they are not uniform, and have allowed the question of their zoonotic potential to be addressed. The focus of this review is the zoonotic potential of the various microsporidia and a brief update on other microsporidia which have no known host or an invertebrate host and which cause rare infections in humans.
Topics: AIDS-Related Opportunistic Infections; Animals; Female; Humans; Mice; Microsporidia; Microsporidiosis; Rabbits; Zoonoses
PubMed: 16020683
DOI: 10.1128/CMR.18.3.423-445.2005 -
Journal of Fungi (Basel, Switzerland) Dec 2015Veterinarians caring for companion animals may encounter microsporidia in various host species, and diagnosis and treatment of these fungal organisms can be particularly... (Review)
Review
Veterinarians caring for companion animals may encounter microsporidia in various host species, and diagnosis and treatment of these fungal organisms can be particularly challenging. Fourteen microsporidial species have been reported to infect humans and some of them are zoonotic; however, to date, direct zoonotic transmission is difficult to document transit through the digestive tract. In this context, summarizing information available about microsporidiosis of companion exotic animals is relevant due to the proximity of these animals to their owners. Diagnostic modalities and therapeutic challenges are reviewed by taxa. Further studies are needed to better assess risks associated with animal microsporidia for immunosuppressed owners and to improve detection and treatment of infected companion animals.
PubMed: 29376921
DOI: 10.3390/jof2010003 -
Parasitology Research Sep 2022Encephalitozoon cuniculi is a microsporidian parasite mostly associated with its natural host, the rabbit (Oryctolagus cuniculus). However, other animals can be... (Review)
Review
Encephalitozoon cuniculi is a microsporidian parasite mostly associated with its natural host, the rabbit (Oryctolagus cuniculus). However, other animals can be infected, like other mammals, birds, and even humans. Although it usually causes subclinical infection, it can also lead to encephalitozoonosis, a clinical disease characterized by neurological, ocular, and/or renal signs that can be even fatal, especially in immunocompromised individuals. Therefore, this multidisciplinary review contributes with updated information about the E. cuniculi, deepening in its molecular and genetic characterization, its mechanisms of infection and transmission, and its prevalence among different species and geographic locations, in a One Health perspective. Recent information about the diagnostic and therapeutic approach in the main host species and the prophylaxis and infection control measures currently suggested are also discussed.
Topics: Animals; Asymptomatic Infections; Encephalitozoon cuniculi; Encephalitozoonosis; Humans; Immunocompromised Host; Mammals; One Health; Rabbits
PubMed: 35840730
DOI: 10.1007/s00436-022-07562-z -
International Journal For Parasitology.... Apr 2016Within the microsporidian genus , three species, , and have been described. Several orders of the Class Aves (Passeriformes, Psittaciformes, Apodiformes,... (Review)
Review
Within the microsporidian genus , three species, , and 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 has a very broad host range while is mainly distributed amongst birds. 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 as well as with or the latter being the most common. Especially, but not exclusively, immunocompromised people are at risk. Environmental contamination with as well as direct transmission of 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, 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.
PubMed: 28560162
DOI: 10.1016/j.ijppaw.2016.01.001