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Advances in Parasitology 2021Enterocytozoon bieneusi is a microsporidian microorganism that causes intestinal disease in animals including humans. E. bieneusi is an obligate intracellular pathogen,... (Review)
Review
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.
Topics: Animals; Enterocytozoon; Food Microbiology; Humans; Microsporidiosis; Prevalence; Water Microbiology; Zoonoses
PubMed: 33482973
DOI: 10.1016/bs.apar.2020.10.001 -
International Journal For Parasitology Sep 2021Canonical microsporidians are a group of obligate intracellular parasites of a wide range of hosts comprising ~1,300 species of >220 genera. Microsporidians are related...
Canonical microsporidians are a group of obligate intracellular parasites of a wide range of hosts comprising ~1,300 species of >220 genera. Microsporidians are related to fungi, and many characterised and uncharacterized groups closely related to them have been discovered recently, filling the knowledge gaps between them. These groups assigned to the superphylum Opisthosporidia have provided several important insights into the evolution of diverse intracellular parasitic lineages within the tree of eukaryotes. The most studied among opisthosporidians, canonical microsporidians, were known to science more than 160 years ago, however, the classification of canonical Microsporidia has been challenging due to common morphological homoplasy, and accelerated evolutionary rates. Instead of morphological characters, ssrRNA sequences have been used as the primary data for the classification of canonical microsporidians. Previous studies have produced a useful backbone of the microsporidian phylogeny, but provided only some nodal support, causing some confusion. Here, we reconstructed phylogenetic trees of canonical microsporidians using Bayesian and Maximum Likelihood inferences. We included rRNA sequences of 126 described/named genera, by far the broadest taxon coverage to date. Overall, our trees show similar topology and recovered four of the five main clades demonstrated in previous studies (Clades 1, 3, 4 and 5). Family level clades were well resolved within each major clade, but many were discordant with the recently revised classification. Therefore, revision and some reshuffling, especially within and between Clades 1 and 3 are required. We also reconstructed phylogenetic trees of Opisthosporidia to better integrate the evolutionary history of canonical microsporidians in a broader context. We discuss several traits shared only by canonical microsporidians that may have contributed to their striking ecological success in diverse metazoans. More targeted studies on the neglected host groups will be of value for a better understanding of the evolutionary history of these interesting intracellular parasites.
Topics: Bayes Theorem; Eukaryota; Microsporidia; Phylogeny; RNA, Ribosomal
PubMed: 33891934
DOI: 10.1016/j.ijpara.2021.02.005 -
Experientia Supplementum (2012) 2022As obligate intracellular parasites with reduced genomes, microsporidia must infect host cells in order to replicate and cause disease. They can initiate infection by...
As obligate intracellular parasites with reduced genomes, microsporidia must infect host cells in order to replicate and cause disease. They can initiate infection by utilizing a harpoon-like invasion organelle called the polar tube (PT). The PT is both visually and functionally a striking organelle and is a characteristic feature of the microsporidian phylum. Outside the host, microsporidia exist as transmissible, single-celled spores. Inside each spore, the PT is arranged as a tight coil. Upon germination, the PT undergoes a large conformational change into a long, linear tube and acts as a tunnel for the delivery of infectious cargo from the spore to a host cell. The firing process is extremely rapid, occurring on a millisecond timescale, and the emergent tube may be as long as 20 times the size of the spore body. In this chapter, we discuss what is known about the structure of the PT, the mechanics of the PT firing process, and how it enables movement of material from the spore body.
Topics: Microsporidia; Organelles; Phagocytosis; Spores, Fungal
PubMed: 35544005
DOI: 10.1007/978-3-030-93306-7_9 -
Experientia Supplementum (2012) 2022Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long...
Microsporidia have drastically modified genomes and cytology resulting from their high level of adaptation to intracytoplasmic parasitism. Their origins, which had long remained enigmatic, were placed within the line of Rozella, a primitive endoparasitic chytrid. These origins became more and more refined with the discovery of various parasites morphologically similar to the primitive lines of microsporidia (Metchnikovellids and Chytridiopsids) but which possess fungal-like genomes and functional mitochondria. These various parasites turn out to be distinct missing links between a large assemblage of chytrid-like rozellids and the true microsporidians, which are actually a very evolved branch of the rozellids themselves. The question of how to consider the historically known Microsporidia and the various microsporidia-like organisms within paraphyletic rozellids is discussed.
Topics: Animals; Fungi; Microsporidia; Parasites; Phylogeny
PubMed: 35543999
DOI: 10.1007/978-3-030-93306-7_3 -
BMC Genomics Apr 2024Congenital infection caused by vertical transmission of microsporidia N. bombycis can result in severe economic losses in the silkworm-rearing industry....
Congenital infection caused by vertical transmission of microsporidia N. bombycis can result in severe economic losses in the silkworm-rearing industry. Whole-transcriptome analyses have revealed non-coding RNAs and their regulatory networks in N. bombycis infected embryos and larvae. However, transcriptomic changes in the microsporidia proliferation and host responses in congenitally infected embryos and larvae remains unclear. Here, we simultaneously compared the transcriptomes of N. bombycis and its host B. mori embryos of 5-day and larvae of 1-, 5- and 10-day during congenital infection. For the transcriptome of N. bombycis, a comparison of parasite expression patterns between congenital-infected embryos and larva showed most genes related to parasite central carbon metabolism were down-regulated in larvae during infection, whereas the majority of genes involved in parasite proliferation and growth were up-regulated. Interestingly, a large number of distinct or shared differentially expressed genes (DEGs) were revealed by the Venn diagram and heat map, many of them were connected to infection related factors such as Ricin B lectin, spore wall protein, polar tube protein, and polysaccharide deacetylase. For the transcriptome of B. mori infected with N. bombycis, beyond numerous DEGs related to DNA replication and repair, mRNA surveillance pathway, RNA transport, protein biosynthesis, and proteolysis, with the progression of infection, a large number of DEGs related to immune and infection pathways, including phagocytosis, apoptosis, TNF, Toll-like receptor, NF-kappa B, Fc epsilon RI, and some diseases, were successively identified. In contrast, most genes associated with the insulin signaling pathway, 2-oxacarboxylic acid metabolism, amino acid biosynthesis, and lipid metabolisms were up-regulated in larvae compared to those in embryos. Furthermore, dozens of distinct and three shared DEGs that were involved in the epigenetic regulations, such as polycomb, histone-lysine-specific demethylases, and histone-lysine-N-methyltransferases, were identified via the Venn diagram and heat maps. Notably, many DEGs of host and parasite associated with lipid-related metabolisms were verified by RT-qPCR. Taken together, simultaneous transcriptomic analyses of both host and parasite genes lead to a better understanding of changes in the microsporidia proliferation and host responses in embryos and larvae in N. bombycis congenital infection.
Topics: Animals; Transcriptome; Larva; Histones; Lysine; Nosema; Gene Expression Profiling; Cell Proliferation; Lipids; Bombyx
PubMed: 38556880
DOI: 10.1186/s12864-024-10236-y -
Experientia Supplementum (2012) 2022Microsporidia 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 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.
Topics: Animals; Enterocytozoon; Feces; Humans; Mammals; Microsporidia; Persistent Infection
PubMed: 35544008
DOI: 10.1007/978-3-030-93306-7_12 -
Parasitology Aug 2020A new microsporidian species, Globosporidium paramecii gen. nov., sp. nov., from Paramecium primaurelia is described on the basis of morphology, fine structure, and SSU...
A new microsporidian species, Globosporidium paramecii gen. nov., sp. nov., from Paramecium primaurelia is described on the basis of morphology, fine structure, and SSU rRNA gene sequence. This is the first case of microsporidiosis in Paramecium reported so far. All observed stages of the life cycle are monokaryotic. The parasites develop in the cytoplasm, at least some part of the population in endoplasmic reticulum and its derivates. Meronts divide by binary fission. Sporogonial plasmodium divides by rosette-like budding. Early sporoblasts demonstrate a well-developed exospore forming blister-like structures. Spores with distinctive spherical shape are dimorphic in size (3.7 ± 0.2 and 1.9 ± 0.2 μm). Both types of spores are characterized by a thin endospore, a short isofilar polar tube making one incomplete coil, a bipartite polaroplast, and a large posterior vacuole. Experimental infection was successful for 5 of 10 tested strains of the Paramecium aurelia species complex. All susceptible strains belong to closely related P. primaurelia and P. pentaurelia species. Phylogenetic analysis placed the new species in the Clade 4 of Microsporidia and revealed its close relationship to Euplotespora binucleata (a microsporidium from the ciliate Euplotes woodruffi), to Helmichia lacustris and Mrazekia macrocyclopis, microsporidia from aquatic invertebrates.
Topics: Microscopy, Electron, Transmission; Microsporidia; Paramecium; Phylogeny
PubMed: 32338239
DOI: 10.1017/S0031182020000633 -
The American Journal of Tropical... May 2023Infections are still among the most important causes of morbidity and mortality in patients with lung cancer, which has the highest rate of cancer-related deaths in the...
Infections are still among the most important causes of morbidity and mortality in patients with lung cancer, which has the highest rate of cancer-related deaths in the world. Microsporidia, which are opportunistic parasitic fungi, primarily localize to the intestine by ingestion but can disseminate to the respiratory tract or can be acquired by spore inhalation. Cancer patients are at higher risk for microsporidia, a life-threatening infection, than the normal population is. We aimed to characterize the prevalence of microsporidia infection for the first time by evaluating the intestinal and respiratory tracts of patients with lung cancer. In this study, we investigated 98 patients with lung cancer and 103 healthy individuals for microsporidia infection and evaluated the clinical findings of patients who were found to be positive. Sputum and stool samples were tested by microscopic examination, in addition to pan-microsporidia and genus-specific polymerase chain reactions. Nine patients with lung cancer had positive results for microsporidia (9.2%), which was significantly higher than the rate in healthy individuals (P = 0.008), and most of them had clinical findings. Among these positive patients, polymerase chain reaction revealed microsporidia in the sputum samples of seven patients, the stool sample of one patient, and both the sputum and stool samples of one patient. Encephalitozoon cuniculi was identified as the predominant pathogen in 87.5% (7/8) of positive sputum samples. Microsporidia infection was significantly associated with advanced stages of cancer. However, in the control group, Encephalitozoon intestinalis was detected in the stool sample of an individual without clinical symptoms. Microsporidia, especially E. cuniculi, should be considered as a cause of respiratory tract infection as well as intestinal infection in cancer patients and should be screened in respiratory samples of these patients when they have pulmonary symptoms.
Topics: Humans; Prevalence; Microsporidiosis; Microsporidia; Lung Neoplasms; Intestines; Feces
PubMed: 36940670
DOI: 10.4269/ajtmh.22-0506 -
Veterinary Medicine and Science May 2022Microsporidia are spore-forming intracellular pathogens with worldwide prevalence, causing emerging infections in humans and animals. Enterocytozoon bieneusi is a... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Microsporidia are spore-forming intracellular pathogens with worldwide prevalence, causing emerging infections in humans and animals. Enterocytozoon bieneusi is a zoonotic species of microsporidia and is responsible for more than 90% of cases of microsporidiosis in humans and animals. Pigs and wild boars are important animal reservoirs of microsporidia. Hence, we aimed to estimate the global prevalence of microsporidia and genetic diversity of E. bieneusi in pigs and wild boars through a set of systematic review and meta-analysis (PRISMA) guidelines.
METHODS
Four databases (Web of Science, PubMed, Scopus and Google Scholar) were searched between January 1, 2000 and April 30, 2021. Regarding meta-analysis, the random-effect model was employed by forest plot with 95% confidence interval (CI).
RESULTS
After exclusion of irrelevant articles and duplication removal, 33 papers, including 34 datasets (30 datasets for domestic pigs and 4 for wild boars) finally meet the inclusion criteria to undergo meta-analysis. The pooled prevalence rates of microsporidia infection in domestic pigs and wild boars were 37.6% (95% CI: 30.8-44.9%) and 8.1% (95% CI: 2.1-26.8%), respectively. While, the pooled prevalence rates of E. bieneusi were 35% (95% CI: 28.4-42.2%) in domestic pigs and 10.1% (95% CI: 1.7-42.4%) in wild boars. The genotypes EbpA was the most reported genotype in domestic pigs and wild boars. Male animals had higher prevalence rates of microsporidia infection than females (27 vs. 17.4%, OR = 1.91; 95% CI, 0.77-4.71%).
CONCLUSION
This study indicates the important role of domestic pigs and wild boars as animal reservoir hosts of microsporidia. Thereby, strategies for control and prevention of these zoonotic pathogens should be designed in pigs and wild boars.
Topics: Animals; Enterocytozoon; Female; Male; Microsporidia; Microsporidiosis; Molecular Epidemiology; Sus scrofa; Swine; Swine Diseases
PubMed: 35113502
DOI: 10.1002/vms3.751 -
Nature Communications May 2023Nosema ceranae is an intracellular parasite invading the midgut of honeybees, which causes serious nosemosis implicated in honeybee colony losses worldwide. The core gut...
Nosema ceranae is an intracellular parasite invading the midgut of honeybees, which causes serious nosemosis implicated in honeybee colony losses worldwide. The core gut microbiota is involved in protecting against parasitism, and the genetically engineering of the native gut symbionts provides a novel and efficient way to fight pathogens. Here, using laboratory-generated bees mono-associated with gut members, we find that Snodgrassella alvi inhibit microsporidia proliferation, potentially via the stimulation of host oxidant-mediated immune response. Accordingly, N. ceranae employs the thioredoxin and glutathione systems to defend against oxidative stress and maintain a balanced redox equilibrium, which is essential for the infection process. We knock down the gene expression using nanoparticle-mediated RNA interference, which targets the γ-glutamyl-cysteine synthetase and thioredoxin reductase genes of microsporidia. It significantly reduces the spore load, confirming the importance of the antioxidant mechanism for the intracellular invasion of the N. ceranae parasite. Finally, we genetically modify the symbiotic S. alvi to deliver dsRNA corresponding to the genes involved in the redox system of the microsporidia. The engineered S. alvi induces RNA interference and represses parasite gene expression, thereby inhibits the parasitism significantly. Specifically, N. ceranae is most suppressed by the recombinant strain corresponding to the glutathione synthetase or by a mixture of bacteria expressing variable dsRNA. Our findings extend our previous understanding of the protection of gut symbionts against N. ceranae and provide a symbiont-mediated RNAi system for inhibiting microsporidia infection in honeybees.
Topics: Bees; Animals; Nosema; Bacteria; Gastrointestinal Microbiome; RNA Interference; Oxidation-Reduction
PubMed: 37210527
DOI: 10.1038/s41467-023-38498-2