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Current Opinion in Microbiology Aug 2015Microsporidia comprise one of the largest groups of obligate intracellular pathogens and can infect virtually all animals, but host response to these fungal-related... (Review)
Review
Microsporidia comprise one of the largest groups of obligate intracellular pathogens and can infect virtually all animals, but host response to these fungal-related microbes has been poorly understood. Several new studies of the host transcriptional response to microsporidia infection have found infection-induced regulation of genes involved in innate immunity, ubiquitylation, metabolism, and hormonal signaling. In addition, microsporidia have recently been shown to exploit host recycling endocytosis for exit from intestinal cells, and to interact with host degradation pathways. Microsporidia infection has also been shown to profoundly affect behavior in insect hosts. Altogether, these and other recent findings are providing much-needed insight into the underlying mechanisms of microsporidia interaction with host animals.
Topics: Animals; Disease Models, Animal; Host-Pathogen Interactions; Humans; Immunity, Innate; Insecta; Microsporidia; Microsporidiosis
PubMed: 25847674
DOI: 10.1016/j.mib.2015.03.006 -
Turkiye Parazitolojii Dergisi 2013All microsporidia are obligate parasites and have no active stages outside their host cells. Microsporidia lack some typical eukaryotic characteristics. There are now... (Review)
Review
All microsporidia are obligate parasites and have no active stages outside their host cells. Microsporidia lack some typical eukaryotic characteristics. There are now over 1200 species identified in 144 genera. The most familiar stage of microsporidia is the small, highly resistant spore, the size of which differs according to the species and is often 1-10 μm. The general life cycle pattern of the microsporidia can be divided into three phases: the infective or environmental phase, the proliferative phase, and the sporogony or spore-forming phase. There are several methods for diagnosing microsporidia: light microscopic, transmission electron microscopy (TEM), immunofluorescence assays (IFA) and molecular methods. The clinical course of microsporidiosis depends on the immune status of the host and site of infection. Microsporidia can cause infections such as diarrhoea, keratitis, myositis, bronchitis and brochiolitis. Human microsporidiosis represents an important and rapidly emerging opportunistic disease, occurring mainly, but not exclusively, in severely immunocompromised patients with AIDS. The treatment of microsporidiosis is generally achieved with medications and supportive care. Depending on the site of infection and the microsporidia species involved, different medications are utilized. The most commonly used medications for microsporidiosis include albendazole and fumagillin.
Topics: Animals; Antifungal Agents; Humans; Immunocompromised Host; Life Cycle Stages; Microsporidia; Microsporidiosis; Opportunistic Infections; Spores, Fungal
PubMed: 23955911
DOI: 10.5152/tpd.2013.28 -
Expert Opinion on Therapeutic Targets Nov 2018Microsporidia have been increasingly reported to infect humans. The most common presentation of microsporidiosis is chronic diarrhea, a significant mortality risk in... (Review)
Review
Microsporidia have been increasingly reported to infect humans. The most common presentation of microsporidiosis is chronic diarrhea, a significant mortality risk in immune-compromised patients. Albendazole, which inhibits tubulin, and fumagillin, which inhibits methionine aminopeptidase type 2 (MetAP2), are the two main therapeutic agents used for treatment of microsporidiosis. In addition, to their role as emerging pathogens in humans, microsporidia are important pathogens in insects, aquaculture, and veterinary medicine. New therapeutic targets and therapies have become a recent focus of attention for medicine, veterinary, and agricultural use. Areas covered: Herein, we discuss the detection and symptoms of microsporidiosis in humans and the therapeutic targets that have been utilized for the design of new drugs for the treatment of this infection, including triosephosphate isomerase, tubulin, MetAP2, topoisomerase IV, chitin synthases, and polyamines. Expert opinion: Enterocytozoon bieneusi is the most common microsporidia in human infection. Fumagillin has a broader anti-microsporidian activity than albendazole and is active against both Ent. bieneusi and Encephaliozoonidae. Microsporidia lack methionine aminopeptidase type 1 and are, therefore, dependent on MetAP2, while mammalian cells have both enzymes. Thus, MetAP2 is an essential enzyme in microsporidia and new inhibitors of this pathway have significant promise as therapeutic agents.
Topics: Albendazole; Animals; Antifungal Agents; Cyclohexanes; Drug Design; Fatty Acids, Unsaturated; Humans; Microsporidia; Microsporidiosis; Molecular Targeted Therapy; Sesquiterpenes
PubMed: 30336698
DOI: 10.1080/14728222.2018.1538360 -
Trends in Parasitology Oct 2017Microsporidia may cause emerging infectious diseases (EIDs) in bumblebees. Two drivers - commercial bumblebees and managed honey bees - have been identified as possible... (Review)
Review
Microsporidia may cause emerging infectious diseases (EIDs) in bumblebees. Two drivers - commercial bumblebees and managed honey bees - have been identified as possible sources of pathogen spillover. In addition, declines in bumblebee populations may have led to lower genetic diversity and subsequent higher susceptibility to infection, enabling microsporidia to increase in prevalence. There is strong evidence for relatively recent increases in the prevalence of Nosema bombi in North America. However, the lack of definitive data on spillover by microsporidia, in North America or elsewhere, makes it difficult to identify the causes of such increases. Phylogenomic studies are urgently needed to identify the global population structure of microsporidia in bumblebees, and thus identify the source of current and future epidemics.
Topics: Animals; Bees; Genetic Variation; North America; Nosema; Phylogeny
PubMed: 28663099
DOI: 10.1016/j.pt.2017.06.001 -
The Journal of Veterinary Medical... Feb 2016Microsporidia are obligate intracellular mitochondria-lacking pathogens that rely on host cells to grow and multiply. Microsporidia, currently classified as fungi, are... (Review)
Review
Microsporidia are obligate intracellular mitochondria-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.
Topics: Animals; Humans; Microsporidia; Microsporidiosis; Mycology; Veterinary Medicine
PubMed: 26346746
DOI: 10.1292/jvms.15-0401 -
Experientia Supplementum (2012) 2022Microsporidia are poorly understood, ubiquitous eukaryotic parasites that are completely dependent on their hosts for replication. With the discovery of microsporidia... (Review)
Review
Microsporidia are poorly understood, ubiquitous eukaryotic parasites that are completely dependent on their hosts for replication. With the discovery of microsporidia species naturally infecting the genetically tractable transparent nematode C. elegans, this host has been used to explore multiple areas of microsporidia biology. Here we review results about microsporidia infections in C. elegans, which began with the discovery of the intestinal-infecting species Nematocida parisii. Recent findings include new species identification in the Nematocida genus, with more intestinal-infecting species, and also a species with broader tissue tropism, the epidermal and muscle-infecting species Nematocida displodere. This species has a longer polar tube infection apparatus, which may enable its wider tissue range. After invasion, multiple Nematocida species appear to fuse host cells, which likely promotes their dissemination within host organs. Localized proteomics identified Nematocida proteins that have direct contact with the C. elegans intestinal cytosol and nucleus, and many of these host-exposed proteins belong to expanded, species-specific gene families. On the host side, forward genetic screens have identified regulators of the Intracellular Pathogen Response (IPR), which is a transcriptional response induced by both microsporidia and the Orsay virus, which is also a natural, obligate intracellular pathogen of the C. elegans intestine. The IPR constitutes a novel immune/stress response that promotes resistance against microsporidia, virus, and heat shock. Overall, the Nematocida/C. elegans system has provided insights about strategies for microsporidia pathogenesis, as well as innate defense pathways against these parasites.
Topics: Animals; Biology; Caenorhabditis elegans; Caenorhabditis elegans Proteins; Host-Pathogen Interactions; Microsporidia
PubMed: 35544001
DOI: 10.1007/978-3-030-93306-7_5 -
Journal of Clinical Microbiology Nov 2014Microsporidia are highly specialized obligate intracellular organisms that are closely related to fungi. Although traditionally associated with diarrheal illness in... (Review)
Review
Microsporidia are highly specialized obligate intracellular organisms that are closely related to fungi. Although traditionally associated with diarrheal illness in patients with AIDS, extraintestinal infections involving various organs have been reported with increasing frequency in the past decade, particularly in immunocompromised hosts. Diagnosis is usually accomplished by light microscopic identification of spores in body fluids and tissues, using a variety of stains. Transmission electron microscopy, immunofluorescence assays, or molecular methods are necessary for identification to the genus and species level. Early diagnosis is essential for preventing the significant associated morbidity and mortality of extraintestinal microsporidiosis.
Topics: Humans; Immunocompromised Host; Microbiological Techniques; Microsporidia; Microsporidiosis
PubMed: 24829239
DOI: 10.1128/JCM.00971-14 -
Trends in Parasitology Aug 2022Microsporidian diversity is vast. There is a renewed drive to understand how microsporidian pathological, genomic, and ecological traits relate to their phylogeny. We... (Review)
Review
Microsporidian diversity is vast. There is a renewed drive to understand how microsporidian pathological, genomic, and ecological traits relate to their phylogeny. We comprehensively sample and phylogenetically analyse 125 microsporidian genera for which sequence data are available. Comparing these results with existing phylogenomic analyses, we suggest an updated taxonomic framework to replace the inconsistent clade numbering system, using informal taxonomic names: Glugeida (previously clades 5/3), Nosematida (4a), Enterocytozoonida (4b), Amblyosporida (3/5), Neopereziida (1), and Ovavesiculida (2). Cellular, parasitological, and ecological traits for 281 well-defined species are compared with identify clade-specific patterns across long-branch Microsporidia. We suggest that future taxonomic circumscriptions of Microsporidia should involve additional markers (SSU/ITS/LSU), and that a comprehensive suite of phenotypic and ecological traits help to predict broad microsporidian functional and lineage diversity.
Topics: Microsporidia; Phylogeny
PubMed: 35667993
DOI: 10.1016/j.pt.2022.05.007 -
PLoS Pathogens Jul 2023Microsporidia are a large phylum of intracellular parasites that can infect most types of animals. Species in the Nematocida genus can infect nematodes including...
Microsporidia are a large phylum of intracellular parasites that can infect most types of animals. Species in the Nematocida genus can infect nematodes including Caenorhabditis elegans, which has become an important model to study mechanisms of microsporidia infection. To understand the genomic properties and evolution of nematode-infecting microsporidia, we sequenced the genomes of nine species of microsporidia, including two genera, Enteropsectra and Pancytospora, without any previously sequenced genomes. Core cellular processes, including metabolic pathways, are mostly conserved across genera of nematode-infecting microsporidia. Each species encodes unique proteins belonging to large gene families that are likely used to interact with host cells. Most strikingly, we observed one such family, NemLGF1, is present in both Nematocida and Pancytospora species, but not any other microsporidia. To understand how Nematocida phenotypic traits evolved, we measured the host range, tissue specificity, spore size, and polar tube length of several species in the genus. Our phylogenetic analysis shows that Nematocida is composed of two groups of species with distinct traits and that species with longer polar tubes infect multiple tissues. Together, our work details both genomic and trait evolution between related microsporidia species and provides a useful resource for further understanding microsporidia evolution and infection mechanisms.
Topics: Animals; Microsporidia; Phylogeny; Nematoda; Caenorhabditis elegans; Genomics
PubMed: 37471459
DOI: 10.1371/journal.ppat.1011510 -
Revista Chilena de Infectologia :... 2018
Topics: Microsporidia; Microsporidiosis
PubMed: 29652974
DOI: 10.4067/s0716-10182018000100073