Microsporidia

{{Short description|Phylum of fungi}} {{About|the parasitic fungi group|the ascomycete fungi genus|Microsporum|the green algae genus|Microspora|the beetle family|Microsporidae}} {{Automatic taxobox | image = Fibrillanosema_spore.jpg | image_caption = [[Sporoblast]] of ''[[Fibrillanosema crangonycis]]'' | taxon = Microsporidia | authority = ex Corliss & Levine 1963 | subdivision_ranks = Orders | subdivision_ref = <ref name="outline24"/> | subdivision = * [[Amblyosporida]] Tokarev & Issi * [[Neopereziida]] Tokarev & Issi * [[Ovavesiculida]] Tokarev & Issi * [[Glugeida]] Gurley [[Emendation (zoology)|emend]]. Tokarev & Issi * [[Nosematida]] Labbe [[Emendation (zoology)|emend]]. Tokarev & Issi (A number of former classes and orders are moved to [[Rozellomycota]].) | synonyms = * Phylum Microsporidiomycota Benny 2007 * Class Microsporidia Balbiani, 1882<ref>{{cite journal | last1 = Balbiani | first1 = G | year = 1882 | title = Sur les microsporidies ou psorospermies des Articulés | url = https://www.biodiversitylibrary.org/item/112005#page/1166/mode/1up | journal = C. R. Acad. Sci. | volume = 95 | pages = 1168–71 }}</ref> * Order Microsporidiida Labbé, 1899 * Order Cnidosporidia Doflein 190? * Class Microsporea Delphy, 1936 [1963], Levine et al., 1980<ref>Delphy, J. 1936. Sous-règne des Protozoaires. In: Perrier, R. (ed.). ''La Faune de la France en tableaux synoptiques illustrés'', vol 1A. Delagrave: Paris.</ref><ref>{{cite journal | last1 = Levine | first1 = N. D. | display-authors = etal | year = 1980 | title = A Newly Revised Classification of the Protozoa | url = https://www.researchgate.net/publication/16209026 | journal = The Journal of Protozoology | volume = 27 | issue = 1 | pages = 37–58 | doi = 10.1111/j.1550-7408.1980.tb04228.x | pmid = 6989987 | doi-access = free }}</ref> * Class Microsporidea Corliss & Levine 1963<ref name=corliss>{{cite journal |vauthors=Corliss JO, Levine ND |year=1963 |title=Establishment of the Microsporidea as a new class in the protozoan subphylum Cnidospora |journal=The Journal of Protozoology |volume=10 |issue=Suppl |pages=26–27 |doi=10.1111/jeu.1963.10.issue-s3 }}</ref> * Phylum Microspora Sprague, 1969, 1977<ref>Sprague, V. (1977). Classification and phylogeny of the Microsporidia. In: ''Comparative pathobiology''. vol. 2, Systematics of the Microsporidia. Lee A. Bulla & Thomas C. Cheng (ed.). pp. 1–30. New York: Plenum Press, [https://books.google.com/books?id=wpnwAAAAMAAJ]. </ref> * Order Microsporida Tuzet et al. 1971 * Class Terresporidia Vossbrinck & Debrunner-Vossbrinck<ref name="outline24">{{cite journal |last1=Hyde |first1=Kd |title=The 2024 Outline of Fungi and fungus-like taxa |journal=Mycosphere |date=2024 |volume=15 |issue=1 |pages=5146–6239 |doi=10.5943/mycosphere/15/1/25|hdl=1854/LU-8660838 |hdl-access=free }}</ref> * Order Microsporidies Balbiani 1882<ref name="Copeland">{{cite book |last1=Copeland |first1=Herbert Faulkner |title=The classification of lower organisms |date=1956 |publisher=Pacific Books |url=https://archive.org/details/classificationof00cope}}</ref> * Order Cryptocystes Gurley 1893<ref name="Copeland"/> }}

'''Microsporidia''' are a group of [[spore]]-forming [[parasite|parasitic]] [[unicellular]] [[fungi]]. These spores contain an extrusion apparatus that has a coiled polar tube ending in an anchoring disc at the apical part of the spore.<ref name="Franzen, C. 2005">Franzen, C. (2005). How do Microsporidia invade cells?. Folia Parasitologica, 52(1–2), 36–40. doi.org/10.14411/fp.2005.005</ref> They were once considered [[protozoa]]ns or [[protist]]s, but are now known to be fungi,<ref>{{cite journal | last1 = Hibbett | first1 = D.S. | display-authors = etal | year = 2007 | title = A higher level phylogenetic classification of the Fungi | url = http://www.umich.edu/~mycology/resources/Publications/Hibbett-et-al.-2007.pdf | journal = Mycological Research | volume = 111 | issue = 5| pages = 509–47 | doi = 10.1016/j.mycres.2007.03.004 | pmid = 17572334 | s2cid = 4686378 }}</ref> or a sister group to [[fungus|true fungi]].<ref name=Silar2016>{{Cite book|last1=Silar|first1=Philippe |title=Protistes Eucaryotes: Origine, Evolution et Biologie des Microbes Eucaryotes |publisher=HAL |year=2016 |page=462 |isbn=978-2-9555841-0-1 | url=https://hal.archives-ouvertes.fr/hal-01263138/document}}</ref> These fungal microbes are obligate eukaryotic parasites that use a unique mechanism to infect host cells.<ref name="Franzen, C. 2005"/> They have recently been discovered in a 2017 Cornell study to infect Coleoptera ([[beetle]]s) on a large scale. So far, about 1500 of the probably more than one million<ref name="Hawksworth, D. 2001">{{cite journal|last1=Hawksworth|first1=David |title=The magnitude of fungal diversity: The 1.5 million spices estimate revisited|journal=Mycological Research|volume=105 |issue=12 |year=2001 |page=1422 |doi=10.1017/S0953756201004725 }}</ref> species are named. Microsporidia are restricted to animal [[host (biology)|host]]s, and all major groups of animals host microsporidia. Most infect [[insect]]s, but they are also responsible for common diseases of [[crustacea]]ns and [[fish]]. The named species of microsporidia usually infect one host species or a group of closely related taxa. Approximately 10 percent of the known species are parasites of vertebrates—several species, most of which are opportunistic, can infect humans, in whom they can cause [[microsporidiosis]].

After infection they influence their hosts in various ways and all organs and tissues are invaded, though generally by different species of specialised microsporidia. Some species are lethal, and a few are used in biological control of insect pests. [[Parasitic castration]], gigantism, or change of host sex are all potential effects of microsporidian parasitism (in insects). In the most advanced cases of parasitism the microsporidium rules the host cell completely and controls its metabolism and reproduction, forming a [[xenoma]].<ref name="lund">Ronny Larsson, Lund University (Department of Cell and Organism Biology) [http://www.cob.lu.se/microsporidia/proj_descr.html#spores ''Cytology and taxonomy of the microsporidia''] {{Webarchive|url=https://web.archive.org/web/20090912100619/http://www.cob.lu.se/microsporidia/proj_descr.html#spores |date=2009-09-12 }} 2004.</ref>

Replication takes place within the host's cells, which are infected by means of unicellular [[spore]]s. These vary from 1–12 μm, making them some of the smallest [[eukaryote]]s.<ref>{{Cite book |url=https://link.springer.com/10.1007/978-3-030-93306-7 |title=Microsporidia: Current Advances in Biology |date=2022 |publisher=Springer International Publishing |isbn=978-3-030-93305-0 |editor-last=Weiss |editor-first=Louis M. |series=Experientia Supplementum |volume=114 |location=Cham |pages=6, 182 |language=en |doi=10.1007/978-3-030-93306-7 |editor-last2=Reinke |editor-first2=Aaron W.}}</ref> Microsporidia that infect [[mammal]]s are 1.0–4.0 μm.<ref name=pmid15777637>{{Cite journal | last1 = Didier | first1 = ES. | title = Microsporidiosis: an emerging and opportunistic infection in humans and animals | journal = Acta Trop | volume = 94 | issue = 1 | pages = 61–76 |date=Apr 2005 | doi = 10.1016/j.actatropica.2005.01.010 | pmid = 15777637 }}</ref> They also have the smallest eukaryotic [[genome]]s.<ref>{{Cite book |url=https://link.springer.com/10.1007/978-3-030-93306-7 |title=Microsporidia: Current Advances in Biology |date=2022 |publisher=Springer International Publishing |isbn=978-3-030-93305-0 |editor-last=Weiss |editor-first=Louis M. |series=Experientia Supplementum |volume=114 |location=Cham |page=3 |language=en |doi=10.1007/978-3-030-93306-7 |editor-last2=Reinke |editor-first2=Aaron W.}}</ref>

The terms "microsporidium" (pl. "microsporidia") and "microsporidian" are used as vernacular names for members of the group. The name ''Microsporidium'' Balbiani, 1884<ref>Balbiani, G. 1884. Les Psorospermies des Articulés ou Microsporidies, pp. 150-168, 184. In: ''Leçons sur les sporozoaires''. Paris: Doin, [https://www.biodiversitylibrary.org/bibliography/932#/summary].</ref> is also used as a catchall genus for [[incertae sedis]] members.<ref>Hoffman, G. (1999). ''Parasites of North American Freshwater Fishes'', 2nd edn, University of California Press, Berkeley, California, USA, p. 89, [https://books.google.com/books?id=ZU5iqP3NJpMC&dq=genus%20Microsporidium&pg=PA89].</ref> [[File:Glugea stephani.jpg|thumb|300px|[[Xenoma]] on flatfish caused by ''[[Glugea]] stephani'']]

== Morphology == [[File:Parasite140027-fig5 Dictyocoela diporeiae Winters & Faisal, 2014 transmission electron micrographs.tif|thumb|left|''Dictyocoela diporeiae''.<ref>{{cite journal | last1 = Winters | first1 = A. D. | last2 = Faisal | first2 = M. | year = 2014 | title = Molecular and ultrastructural characterization of ''Dictyocoela diporeiae'' n. sp. (Microsporidia), a parasite of ''Diporeia'' spp. (Amphipoda, Gammaridea) | journal = Parasite | volume = 21 | page = 26 | doi = 10.1051/parasite/2014028 | pmid = 24934702 | pmc = 4059264 | doi-access = free }}</ref> A, meront and spore; B, spore wall; C, polar filament]] Microsporidia lack [[mitochondrion|mitochondria]], instead possessing [[mitosome]]s. They also lack motile structures, such as [[flagellum|flagella]].

Microsporidia produce highly resistant spores, capable of surviving outside their host for up to several years. Spore morphology is useful in distinguishing between different species. Spores of most species are oval or pyriform, but rod-shaped or spherical spores are not unusual. A few genera produce spores of unique shape for the genus.

The spore is protected by a wall, consisting of three layers: *an outer electron-dense ''exospore'' *a median, wide and seemingly structureless ''endospore'', containing [[chitin]] *a thin internal ''plasma membrane''

In most cases there are two closely associated [[cell nucleus|nuclei]], forming a ''[[diplokaryon]]'', but sometimes there is only one. The anterior half of the spore contains a harpoon-like apparatus with a long, thread-like ''polar filament'', which is coiled up in the posterior half of the spore. The anterior part of the polar filament is surrounded by a ''polaroplast'', a lamella of membranes. Behind the polar filament, there is a posterior ''vacuole''.<ref name="lund"/>

== Infection == The spore germinates in the gut of the host; it builds up osmotic pressure until its rigid wall ruptures at its thinnest point at the apex. The posterior vacuole swells, forcing the polar filament to rapidly eject the infectious content into the cytoplasm of the potential host. Simultaneously the material of the filament is rearranged to form a tube which functions as a hypodermic needle and penetrates the gut epithelium. Once inside the host cell, a [[sporoplasm]] grows, dividing or forming a [[multinucleate]] [[plasmodium (life cycle)|plasmodium]], before producing new spores. The life cycle varies considerably. Some have a simple [[asexual reproduction|asexual]] life cycle,<ref name="pmid17394631">{{cite journal |author=Ironside JE |title=Multiple losses of sex within a single genus of Microsporidia |journal=BMC Evolutionary Biology |volume=7|page=48 |year=2007 |pmid=17394631 |pmc=1853083 |doi=10.1186/1471-2148-7-48 |doi-access=free }}</ref> while others have a complex life cycle involving multiple hosts and both asexual and [[sexual reproduction]]. Different types of spores may be produced at different stages, probably with different functions including [[autoinfection]] (transmission within a single host).

== Medical implications == In animals and humans, microsporidia often cause chronic, debilitating diseases rather than lethal infections. Effects on the host include reduced longevity, fertility, weight, and general vigor. [[Vertical transmission]] of microsporidia is frequently reported.

In the case of insect hosts, vertical transmission often occurs as [[transovarial]] transmission, where the microsporidian parasites pass from the ovaries of the female host into eggs and eventually multiply in the infected larvae. ''[[Amblyospora|Amblyospora salinaria]]'' n. sp. which infects the mosquito ''[[Culex salinarius]]'' Coquillett, and ''[[Amblyospora|Amblyospora californica]]'' which infects the mosquito ''[[Culex|Culex tarsalis]]'' Coquillett, provide typical examples of transovarial transmission of microsporidia.<ref>{{cite journal |vauthors=Andreadis TG, Hall DW |title=Development, ultrastructure, and mode of transmission of Amblyospora sp. (Microspora) in the mosquito |journal=The Journal of Protozoology |volume=26 |issue=3 |pages=444–52 |date=August 1979 |pmid=536933 |doi=10.1111/j.1550-7408.1979.tb04651.x}}</ref><ref>{{cite journal |vauthors=Andreadis TG, Hall DW |title=Significance of transovarial infections of Amblyospora sp. (Microspora:Thelohaniidae) in relation to parasite maintenance in the mosquito Culex salinarius |journal=Journal of Invertebrate Pathology |volume=34 |issue=2 |pages=152–7 |date=September 1979 |pmid=536610 |doi=10.1016/0022-2011(79)90095-8}}</ref><ref>{{cite journal |vauthors=Jahn GC, Hall DW, Zam SG |year=1986 |title=A comparison of the life cycles of two Amblyospora (Microspora: Amblyosporidae) in the mosquitoes ''Culex salinarius'' and ''Culex tarsalis'' Coquillett |journal=Journal of the Florida Anti-Mosquito Association |volume=57 |issue=1 |pages=24–27}}</ref><ref>{{cite journal |vauthors=Becnel JJ, Andreadis TG |title=''Amblyospora salinaria'' n. sp. (Microsporidia: amblyosporidae), parasite of ''Culex salinarius'' (Diptera: culicidae): its life cycle stages in an intermediate host |journal=Journal of Invertebrate Pathology |volume=71 |issue=3 |pages=258–62 |date=May 1998 |pmid=9538031 |doi=10.1006/jipa.1998.4729|url=https://zenodo.org/record/1229866 }}</ref> Microsporidia, specifically the mosquito-infecting ''[[Vavraia culicis]]'', are being explored as a possible 'evolution-proof' malaria-control method.<ref>{{Cite book|first1=Jacob C. |last1=Koella |first2=Lena |last2=Lorenz |first3=Irka |last3=Bargielowski |year=2009 |title=Chapter 12 Microsporidians as Evolution-Proof Agents of Malaria Control?|volume=68|pages=315–327 |pmid=19289199|doi=10.1016/S0065-308X(08)00612-X|series=Advances in Parasitology|isbn=978-0-12-374787-7}}</ref> Microsporidian infection of ''[[Anopheles gambiae]]'' (the principal vector of ''[[Plasmodium falciparum]]'' malaria) reduces malarial infection within the mosquito, and shortens the mosquito lifespan.<ref>{{cite journal |vauthors=Bargielowski I, Koella JC |title=A Possible Mechanism for the Suppression of Plasmodium berghei Development in the Mosquito Anopheles gambiae by the Microsporidian Vavraia culicis |journal=PLOS ONE |volume=4 |issue=3 |article-number=e4676 |year=2009 |pmid=19277119 |pmc=2651578 |doi=10.1371/journal.pone.0004676 |editor1-last=Baylis |editor1-first=Matthew|bibcode=2009PLoSO...4.4676B |doi-access=free }}</ref> As the majority of malaria-infected mosquitoes naturally die before the malaria parasite is mature enough to transmit, any increase in mosquito mortality through microsporidian-infection may reduce malaria transmission to humans. In May 2020, researchers reported that ''Microsporidia MB'', a symbiont in the midgut and ovaries of ''[[Anopheles arabiensis]]'', significantly impaired transmission of ''P. falciparum'', had "no overt effect" on the fitness of host mosquitoes, and was transmitted vertically (through inheritance).<ref>{{cite journal |display-authors = etal |last1 = Herren |first1 = JK |last2 = Mbaisi |first2 = L |last3 = Mararo |first3 = E |title=A microsporidian impairs ''Plasmodium falciparum'' transmission in ''Anopheles arabiensis'' mosquitoes |journal=Nature Communications |volume=11 |issue=2187 |year=2020 |page = 2187 |doi=10.1038/s41467-020-16121-y|pmid = 32366903 |pmc = 7198529 |bibcode = 2020NatCo..11.2187H |doi-access = free }}</ref>

===Clinical=== {{Main|Microsporidiosis}}

{{expand section|date=November 2013}} Microsporidian infections of humans sometimes cause a disease called [[microsporidiosis]]. At least 14 microsporidian species, spread across eight genera, have been recognized as human [[pathogen]]s. These include ''[[Trachipleistophora hominis]]''.<ref>{{cite journal | last1 = Heinz | first1 = E | last2 = Williams | first2 = TA | last3 = Nakjang | first3 = S | last4 = Noël | first4 = CJ | last5 = Swan | first5 = DC | last6 = Goldberg | first6 = AV | last7 = Harris | first7 = SR | last8 = Weinmaier | first8 = T | last9 = Markert | first9 = S |date=Oct 2012 | title = The genome of the obligate intracellular parasite ''Trachipleistophora hominis'': New insights into microsporidian genome dynamics and reductive evolution | journal = PLOS Pathog | volume = 8 | issue = 10| article-number = e1002979 | doi = 10.1371/journal.ppat.1002979 | pmid = 23133373 | pmc = 3486916 | display-authors = 3 | last10 = Bernhardt | first10 = Jörg | last11 = Dagan | first11 = Tal | last12 = Hacker | first12 = Christian | last13 = Lucocq | first13 = John M. | last14 = Schweder | first14 = Thomas | last15 = Rattei | first15 = Thomas | last16 = Hall | first16 = Neil | last17 = Hirt | first17 = Robert P. | last18 = Embley | first18 = T. Martin | doi-access = free }}</ref>

==As hyperparasites== [[File:Parasite140019-fig4 Nosema podocotyloidis - Hyperparasitic Microsporidia.tif|thumb|A hyperparasitic microsporidian, ''Nosema podocotyloidis'', a parasite of a [[digenea]]n which is itself a parasite of a fish.<ref name=Toguebaye/>]]

Microsporidia can infect a variety of hosts, including hosts which are themselves parasites. In that case, the microsporidian species is a [[hyperparasite]], i.e. a parasite of a parasite. As an example, more than eighteen species are known which parasitize [[digenea]]ns (parasitic [[flatworm]]s). These digeneans are themselves parasites in various [[vertebrate]]s and [[mollusc]]s. Eight of these species belong to the genus ''[[Nosema (microsporidian)|Nosema]]''.<ref name=Toguebaye>{{cite journal | last1 = Toguebaye | first1 = B. S. | last2 = Quilichini | first2 = Y. | last3 = Diagne | first3 = P. M. | last4 = Marchand | first4 = B. | year = 2014 | title = Ultrastructure and development of ''Nosema podocotyloidis'' n. sp. (Microsporidia), a hyperparasite of ''Podocotyloides magnatestis'' (Trematoda), a parasite of ''Parapristipoma octolineatum'' (Teleostei) | journal = Parasite | volume = 21 | page = 44 | doi = 10.1051/parasite/2014044 | pmid = 25174849 | pmc = 4150386 }} {{open access}}</ref> Similarly, the microsporidian species ''Toguebayea baccigeri'' is a parasite of a digenean, the faustulid ''Bacciger israelensis'', itself an intestinal parasite of a marine fish, the bogue ''[[Boops boops]]'' (Teleostei, Sparidae).<ref name="Miquel2022">{{cite journal | last1=Miquel | first1=Jordi | last2=Kacem | first2=Hichem | last3=Baz-González | first3=Edgar | last4=Foronda | first4=Pilar | last5=Marchand | first5=Bernard | title=Ultrastructural and molecular study of the microsporidian ''Toguebayea baccigeri'' n. gen., n. sp., a hyperparasite of the digenean trematode ''Bacciger israelensis'' (Faustulidae), a parasite of ''Boops boops'' (Teleostei, Sparidae) | journal=Parasite | publisher=EDP Sciences | volume=29 | year=2022 | issn=1776-1042 | doi=10.1051/parasite/2022007 | page=2| pmid=35103588 | pmc=8805611 | s2cid=246443154 }} {{open access}}</ref>

==Genomes== Microsporidia have the smallest known (nuclear) eukaryotic [[genome]]s. The parasitic lifestyle of microsporidia has led to a loss of many [[mitochondria]]l and [[Golgi apparatus|Golgi]] genes, and even their [[ribosomal RNA]]s are reduced in size compared with those of most [[eukaryote]]s. As a consequence, the genomes of microsporidia are much smaller than those of other eukaryotes. Currently known microsporidial genomes are 2.5 to 11.6 Mb in size, encoding from 1,848 to 3,266 proteins which is in the same range as many [[bacteria]].<ref name="Conradi2013">{{Cite journal | last1 = Corradi | first1 = N. | last2 = Selman | first2 = M. | doi = 10.1111/jeu.12030 | title = Latest Progress in Microsporidian Genome Research | journal = Journal of Eukaryotic Microbiology | volume = 60 | issue = 3 | pages = 309–312 | year = 2013 | pmid = 23445243 | s2cid = 24504235 }}</ref>

Genomic and epigenetic architecture vary significantly across different species in Microsporidia. Some variable characteristics are nucleotidic composition, gene location in the chromosome or methylation levels in coding regions. Ribosomal RNA genes are located in the subtelomeric chromosomal regions in species like ''Encephalitozoon'', while other species have radically different architectures. Hipermethylation in ribosomal RNA is highly preserved, regardless of its position in the genome. Guanine and cytosine content is negatively associated to genome size. Therefore, larger genomes will have a smaller proportion of guanine and cytosine.<ref>{{Cite journal |last1=Angst |first1=Pascal |last2=Ebert |first2=Dieter |last3=Fields |first3=Peter D. |date=2025-09-02 |title=Variation in Genome Architecture and Epigenetic Modification Across the Microsporidia Phylogeny |journal=Genome Biology and Evolution |volume=17 |issue=9 |article-number=evaf166 |doi=10.1093/gbe/evaf166 |issn=1759-6653 |pmc=12449221 |pmid=40857611}}</ref>

[[Horizontal gene transfer]] (HGT) seems to have occurred many times in microsporidia. For instance, the genomes of ''[[Encephalitozoon romaleae]]'' and ''[[Trachipleistophora hominis]]'' contain genes that derive from animals and bacteria, and some even from fungi.<ref name="Conradi2013" />

==DNA repair==

The [[RAD9A|Rad9]]-[[RAD1 homolog|Rad1]]-Hus1 protein complex (also known as the 9-1-1 complex) in eukaryotes is recruited to sites of [[DNA damage (naturally occurring)|DNA damage]] where it is considered to help trigger the checkpoint-signaling cascade. Genes that code for heterotrimeric 9-1-1 are present in microsporidia.<ref name = Santos2022>{{cite journal|vauthors=Mascarenhas Dos Santos AC, Julian AT, Pombert JF|title=The Rad9-Rad1-Hus1 DNA Repair Clamp is Found in Microsporidia|journal=Genome Biology and Evolution|date=2022-04-10|volume=14|issue=4|article-number=evac053|doi=10.1093/gbe/evac053|pmid=35439302|pmc=9053307}}</ref> In addition to the 9-1-1 complex, other components of the [[DNA repair]] machinery are also present indicting that repair of DNA damage likely occurs in microsporidia.<ref name = Santos2022/>

==Phylogeny== Phylogeny of Rozellomycota. Backbone from SSU rRNA in Wijayawardene et al. (2020);<ref name="Wijayawardene_2020">{{Cite journal |display-authors=6 |vauthors=Wijayawardene NN, Hyde KD, Al-Ani LK, Tedersoo L, Haelewaters D, Rajeshkumar KC, Zhao RL, Aptroot A, Leontyev DV, Saxena RK, Tokarev YS, Dai DQ, Letcher PM, Stephenson SL, Ertz D, Lumbsch HT, Kukwa M, Issi IV, Madrid H, Phillips AJ, Selbmann L, Pfliegler WP, Horváth E, Bensch K, Kirk PM, Kolaříková K, Raja HA, Radek R, Papp V, Dima B, Ma J, Malosso E, Takamatsu S, Rambold G, Gannibal PB, Triebel D, Gautam AK, Avasthi S, Suetrong S, Timdal E, Fryar SC, Delgado G, Réblová M, Doilom M, Dolatabadi S, Pawłowska J, Humber RA, Kodsueb R, Sánchez-Castro I, Goto BT, Silva DK, de Souza FA, Oehl F, da Silva GA, Silva IR, Błaszkowski J, Jobim K, Maia LC, Barbosa FR, Fiuza PO, Divakar PK, Shenoy BD, Castañeda-Ruiz RF, Somrithipol S, Lateef AA, Karunarathna SC, Tibpromma S, Mortimer PE, Wanasinghe DN, Phookamsak R, Xu J, Wang Y, Tian F, Alvarado P, Li DW, Kušan I, Matočec N, Maharachchikumbura SS, Papizadeh M, Heredia G, Wartchow F, Bakhshi M, Boehm E, Youssef N, Hustad VP, Lawrey JD, Santiago AL, Bezerra JD, Souza-Motta CM, Firmino AL, Tian Q, Houbraken J, Hongsanan S, Tanaka K, Dissanayake AJ, Monteiro JS, Grossart HP, Suija A, Weerakoon G, Etayo J, Tsurykau A, Vázquez V, Mungai P, Damm U, Li QR, Zhang H, Boonmee S, Lu YZ, Becerra AG, Kendrick B, Brearley FQ, Motiejūnaitė J, Sharma B, Khare R, Gaikwad S, Wijesundara DS, Tang LZ, He MQ, Flakus A, Rodriguez-Flakus P, Zhurbenko MP, McKenzie EH, Stadler M, Bhat DJ, Liu JK, Raza M, Jeewon R, Nassonova ES, Prieto M, Jayalal RG, Erdoğdu M, Yurkov A, Schnittler M, Shchepin ON, Novozhilov YK, Silva-Filho AG, Liu P, Cavender JC, Kang Y, Mohammad S, Zhang LF, Xu RF, Li YM, Dayarathne MC, Ekanayaka AH, Wen TC, Deng CY, Pereira OL, Navathe S, Hawksworth DL, Fan XL, Dissanayake LS, Kuhnert E, Grossart HP, Thines M |title = Outline of Fungi and fungus-like taxa |journal=Mycosphere |year=2020 |volume=11 |issue=1 |pages=1060–1456 |url=http://www.mycosphere.org/pdf/MYCOSPHERE_11_1_8-1.pdf |issn=2077-7019 |doi=10.5943/mycosphere/11/1/8 |pmid= |doi-access=free }}</ref> ''Mitosporidium'', ''Morellospora'', and Microsporidia s.l. from SSU rRNA in Corsaro et al. (2020);<ref name="Morellospora">{{cite journal |last1=Corsaro |first1=Daniele |last2=Walochnik |first2=Julia |last3=Venditti |first3=Danielle |last4=Hauröder |first4=Bärbel |last5=Michel |first5=Rolf |title=Solving an old enigma: Morellospora saccamoebae gen. nov., sp. nov. (Rozellomycota), a Sphaerita-like parasite of free-living amoebae |journal=Parasitology Research |date=March 2020 |volume=119 |issue=3 |pages=925–934 |doi=10.1007/s00436-020-06623-5 |pmid=32048025 }}</ref> internals of Microsporidia s.s. from SSU rRNA in Bojko et al. (2022).<ref name=Bojko>{{Cite journal |last1=Bojko |first1=Jamie |last2=Reinke |first2=Aaron W. |last3=Stentiford |first3=Grant D. |last4=Williams |first4=Bryony |last5=Rogers |first5=Martin S.J. |last6=Bass |first6=David | title=Microsporidia: a new taxonomic, evolutionary, and ecological synthesis |journal=Trends in Parasitology |year=2022 |volume=38 |issue=8 |pages=642–659 |url= |doi=10.1016/j.pt.2022.05.007 |pmid= |doi-access=free}}</ref>

{{clade|style=font-size:90%;line-height:100%;width:350px |label1=[[Rozellomyceta]] |1={{clade |1=''Rozella'' |label2=[[Microsporidiomycota]]{{efn|Treatment not accepted by the 2020, 2022,<ref name=OOF2022/> or 2024 ''Outlines'', which treat this node as having no taxonomic value, and puts all of Rozellomyceta under Rozellomycta.|name=outline}} |2={{clade |1={{clade |1={{clade |1=''[[Mitosporidium]]'' |2=''[[Morellospora]]'' }} }} |2={{clade |1=''[[Paramicrosporidium]]'' |2={{clade |1=''[[Nucleophaga]]'' |label2='''Microsporidia''' s.l. |2={{clade |1={{clade |label1=[[Chytridiopsidea]] |1=[[Chytridiopsida]] }} |2={{clade |label1=[[Metchnikovellea]] |1=Metchnikovellida |label2=Microsporidea |sublabel2='''Microsporidia''' s.s. |2={{clade |1=Neopereziida |2={{clade |1=Ovavesiculida |2={{clade |1=Amblyosporida |2={{clade |1={{clade|1=Glugeida|2="Orphan lineage"}} |2={{clade|1=Nosematida|2=Enterocytozoonida}} }} }} }} }} }} }} }} }} }} }} }}

Node 1: The "Orphan lineage" includes ''[[Hamiltosporidium]]'' + ''[[Astathelohania]]''. ''[[Neofabelliforma]]'' and ''[[Areospora]]'' are possible inclusions but support is weak.<ref name=Bojko/>

Note 2: The presence of Enterocytozoonida (Mrazekiidae + Enterocytozoonidae) indicates a "splitter" view of Nosematida in Bojko et al. (2022). In the 2024 ''Outline'', the two families are subsumed into Nosematida.

Note 3: Amblyosporida has also been split into Caudosporida (Caudosporidae) and a smaller Amblyosporida (Amblyosporidae + Gurleyidae). This is used with some doubt in Bojko et al. (2022). The ''Outline'' takes a lumper view.<ref name=Bojko/>

Note 4: Microsporida s.s. is the "classical" scope of the class used by the ''Outline'' and Bojko et al. (2022). Some authors such as Corsaro et al. (2020) defines a larger scope, noted as Microsporida s.l. here.

=== Alternative topologies === Bojko et al. (2022) also includes a different branching order recovered by both Cormier et al. (2021) and Wadi and Reinke (2020), using a phylogenomic (multilocus) approach<ref name=Bojko/> with 68 single-copy genes. This branching order indicates:<ref>{{cite journal |last1=Cormier |first1=A |last2=Wattier |first2=R |last3=Giraud |first3=I |last4=Teixeira |first4=M |last5=Grandjean |first5=F |last6=Rigaud |first6=T |last7=Cordaux |first7=R |title=Draft Genome Sequences of Thelohania contejeani and Cucumispora dikerogammari, Pathogenic Microsporidia of Freshwater Crustaceans. |journal=Microbiology Resource Announcements |date=14 January 2021 |volume=10 |issue=2 |article-number=e01346-20 |doi=10.1128/MRA.01346-20 |doi-access=free|pmid=33446596|pmc=7849709 }}</ref>

{{clade |label1=[[Metchnikovellea]] |1=Metchnikovellida |label2=Microsporidea |sublabel2='''Microsporidia''' s.s. |2={{clade |1=Ovavesiculida |2={{clade |1=Glugeida |2={{clade |1={{clade|1=Amblyosporida|2="Orphan lineage"}} |2={{clade |1=Neopereziida |2={{clade|1=Nosematida|2=Enterocytozoonida}} }} }} }} }} }}

South et al. (2024), quoting Corsano (2022), gives the following alternative topology for Microsporidia s.l.:<ref name=South>{{cite journal |last1=South |first1=Lilith R. |last2=Hurdeal |first2=Vedprakash G. |last3=Fast |first3=Naomi M. |title=Genomics and phylogenetic relationships of microsporidia and their relatives |journal=Journal of Eukaryotic Microbiology |date=September 2024 |volume=71 |issue=5 |article-number=e13051 |doi=10.1111/jeu.13051|doi-access=free }}</ref>

{{clade|1=''Paramicrosporidium''|label2=Microsporidia s.l.|2= {{clade |1='''Microsporidia''' s.s. |2={{clade|1=''Nucleophaga''|2={{clade|1=Chytridiopsida|2=Metchnikovellea}}}}}}}}

South et al. (2024) marks the above internal topology of Microsporidia s.l. as robust to newer genome-based (multiprotein) studies, namely de Albuquerque & Haag, 2023; Thomé et al., 2023; Williams et al., 2022.<ref name=South/>

== Classification == {{Further|Wikispecies:Microsporidia}} The first described microsporidian genus, ''[[Nosema (microsporidian)|Nosema]]'', was initially put by [[Carl Nägeli|Nägeli]] in the fungal group [[Schizomycetes]] together with some [[bacteria]] and [[yeasts]].<ref>{{cite journal | last1 = Nägeli | first1 = C. von | year = 1857 | title = Über die neue Krankheit der Seidenraupe und verwandte Organismen. pp. 760–61. In: Caspary, R. (ed.). Bericht über die Verhandlungen der 33. Versammlung deutscher Naturforscher und Aerzte, gehalten in Bonn von 18 bis 24 September 1857 | url = https://archive.org/stream/botanischezeitun15mohl#page/374/mode/2up | journal = Botanische Zeitung | volume = 15 | pages = 749–776 }}</ref><ref>{{cite journal | last1 = Keeling | first1 = P. J. | last2 = Fast | first2 = N. M. | year = 2002 | title = Microsporidia: biology and evolution of highly reduced intracellular parasites | url = http://www3.botany.ubc.ca/keeling/PDF/02microARM.pdf | journal = Annual Review of Microbiology | volume = 56 | issue = 1| pages = 93–116 | doi = 10.1146/annurev.micro.56.012302.160854 | pmid = 12142484 }}</ref> For some time microsporidia were considered as very primitive eukaryotes, placed in the protozoan group [[Cnidospora]].<ref name=corliss /> Later, especially because of the lack of mitochondria, they were placed along with the other [[Protozoa]] such as [[diplomonad]]s, [[parabasalid]]s and [[archamoebae]] in the [[protozoa]]n-group [[Archezoa]].<ref>{{cite journal | last1 = Cavalier-Smith | first1 = T | year = 1993 | title = Kingdom protozoa and its 18 phyla | url= | journal = Microbiological Reviews | volume = 57 | issue = 4| pages = 953–994 | doi = 10.1128/MR.57.4.953-994.1993 | pmid = 8302218 | pmc = 372943 }}</ref> More recent research has falsified this theory of early origin (for all of these). Instead, microsporidia are proposed to be highly developed and specialized organisms, which just dispensed functions that are needed no longer, because they are supplied by the host.<ref name="Keeling">{{cite journal |vauthors=Keeling PJ, Slamovits CH |title=Simplicity and Complexity of Microsporidian Genomes |journal=Eukaryotic Cell |volume=3 |issue=6 |pages=1363–9 |date=December 2004 |pmid=15590811 |pmc=539024 |doi=10.1128/EC.3.6.1363-1369.2004}}</ref> Furthermore, spore-forming organisms in general do have a complex system of reproduction, both sexual and asexual, which look far from primitive.

Since the mid-2000s microsporidia are placed within the Fungi or as a sister-group of the Fungi with a common ancestor.<ref>{{cite journal |vauthors=Fischer WM, Palmer JD |title=Evidence from small-subunit ribosomal RNA sequences for a fungal origin of Microsporidia |journal=Molecular Phylogenetics and Evolution |volume=36 |issue=3 |pages=606–22 |date=September 2005 |pmid=15923129 |doi=10.1016/j.ympev.2005.03.031}}</ref><ref>{{cite journal |vauthors=Liu YJ, Hodson MC, Hall BD |title=Loss of the flagellum happened only once in the fungal lineage: phylogenetic structure of Kingdom Fungi inferred from RNA polymerase II subunit genes |journal=BMC Evolutionary Biology |volume=6|page=74 |year=2006 |pmid=17010206 |pmc=1599754 |doi=10.1186/1471-2148-6-74 |doi-access=free }}</ref><ref>{{cite journal |vauthors=Gill EE, Fast NM |title=Assessing the microsporidia-fungi relationship: Combined phylogenetic analysis of eight genes |journal=Gene |volume=375 |pages=103–9 |date=June 2006 |pmid=16626896 |doi=10.1016/j.gene.2006.02.023}}</ref><ref>{{cite journal |vauthors=Lee SC, Corradi N, Byrnes EJ, etal |title=Microsporidia evolved from ancestral sexual fungi |journal=Current Biology |volume=18 |issue=21 |pages=1675–9 |date=November 2008 |pmid=18976912 |doi=10.1016/j.cub.2008.09.030 |pmc=2654606 }}</ref> To avoid destructive changes to lower classification, the ''[[International Code of Nomenclature for algae, fungi, and plants]]'' explicitly excludes Microsporidia since 2012, leaving it to the ''[[International Code of Zoological Nomenclature]]'' as is traditionally done.<ref>{{cite web |title=International Code of Nomenclature for algae, fungi, and plants: Melbourne Code (2012): Premeable |url=https://www.iapt-taxon.org/melbourne/main.php?page=pre |website=www.iapt-taxon.org |quote=8. The provisions of this Code apply to all organisms traditionally treated as algae, fungi, or plants, whether fossil or non-fossil, including blue-green algae (Cyanobacteria)[3], chytrids, oomycetes, slime moulds, and photosynthetic protists with their taxonomically related non-photosynthetic groups (but excluding Microsporidia). Provisions for the names of hybrids appear in Appendix I.}}</ref>

Early work to identify clades is largely based on habitat and host. Three classes of Microsporidia are proposed by Vossbrinck and Debrunner-Vossbrinck in 2005, based on the habitat: Aquasporidia, Marinosporidia and Terresporidia.<ref>{{cite journal |vauthors=Vossbrinck CR, Debrunner-Vossbrinck BA |title=Molecular phylogeny of the Microsporidia: ecological, ultrastructural and taxonomic considerations |journal=Folia Parasitologica |volume=52 |issue=1–2 |pages=131–42; discussion 130 |date=May 2005 |pmid=16004372 |doi=10.14411/fp.2005.017|doi-access=free }}</ref>

A second classification by Cavalier-Smith 1993:<ref>{{cite journal |author=Cavalier-Smith |title=Kingdom Protozoa and its 18 phyla |journal=Microbiological Reviews |date=1993 |volume=57 |issue=4 |pages=953–94 |doi=10.1128/MR.57.4.953-994.1993 |pmid=8302218 |pmc=372943 | url=}}</ref> * Subphyla [[Rudimicrospora]] Cavalier-Smith 1993 ** Class [[Minisporea]] Cavalier-Smith 1993 *** Order [[Minisporida]] Sprague, 1972 ** Class [[Metchnikovellea]] Weiser, 1977 *** Order [[Metchnikovellida]] Vivier, 1975 * Subphyla [[Polaroplasta]] Cavalier-Smith 1993 ** Class [[Pleistophoridea]] Cavalier-Smith 1993 *** Order [[Pleistophorida]] Stempell 1906 ** Class [[Disporea]] Cavalier-Smith 1993 *** Subclass [[Unikaryotia]] Cavalier-Smith 1993 *** Subclass [[Diplokaryotia]] Cavalier-Smith 1993

{| |- | {|class="wikitable" |- ! colspan=1 |Alimov 2007 <ref>{{cite book |editor=Alimov, A. F. |title=Protista 2: Handbook on zoology |publisher=Nauka |page=1141 |date=May 2007 |isbn=978-5-02-026224-9 | url=https://books.google.com/books?id=FVFQAAAAYAAJ }}</ref> ! colspan=1 |Wijayawardene et al. 2024<ref name="Wijayawardene_2020">{{Cite journal |display-authors=6 |vauthors=Wijayawardene NN, Hyde KD, Al-Ani LK, Tedersoo L, Haelewaters D, Rajeshkumar KC, Zhao RL, Aptroot A, Leontyev DV, Saxena RK, Tokarev YS, Dai DQ, Letcher PM, Stephenson SL, Ertz D, Lumbsch HT, Kukwa M, Issi IV, Madrid H, Phillips AJ, Selbmann L, Pfliegler WP, Horváth E, Bensch K, Kirk PM, Kolaříková K, Raja HA, Radek R, Papp V, Dima B, Ma J, Malosso E, Takamatsu S, Rambold G, Gannibal PB, Triebel D, Gautam AK, Avasthi S, Suetrong S, Timdal E, Fryar SC, Delgado G, Réblová M, Doilom M, Dolatabadi S, Pawłowska J, Humber RA, Kodsueb R, Sánchez-Castro I, Goto BT, Silva DK, de Souza FA, Oehl F, da Silva GA, Silva IR, Błaszkowski J, Jobim K, Maia LC, Barbosa FR, Fiuza PO, Divakar PK, Shenoy BD, Castañeda-Ruiz RF, Somrithipol S, Lateef AA, Karunarathna SC, Tibpromma S, Mortimer PE, Wanasinghe DN, Phookamsak R, Xu J, Wang Y, Tian F, Alvarado P, Li DW, Kušan I, Matočec N, Maharachchikumbura SS, Papizadeh M, Heredia G, Wartchow F, Bakhshi M, Boehm E, Youssef N, Hustad VP, Lawrey JD, Santiago AL, Bezerra JD, Souza-Motta CM, Firmino AL, Tian Q, Houbraken J, Hongsanan S, Tanaka K, Dissanayake AJ, Monteiro JS, Grossart HP, Suija A, Weerakoon G, Etayo J, Tsurykau A, Vázquez V, Mungai P, Damm U, Li QR, Zhang H, Boonmee S, Lu YZ, Becerra AG, Kendrick B, Brearley FQ, Motiejūnaitė J, Sharma B, Khare R, Gaikwad S, Wijesundara DS, Tang LZ, He MQ, Flakus A, Rodriguez-Flakus P, Zhurbenko MP, McKenzie EH, Stadler M, Bhat DJ, Liu JK, Raza M, Jeewon R, Nassonova ES, Prieto M, Jayalal RG, Erdoğdu M, Yurkov A, Schnittler M, Shchepin ON, Novozhilov YK, Silva-Filho AG, Liu P, Cavender JC, Kang Y, Mohammad S, Zhang LF, Xu RF, Li YM, Dayarathne MC, Ekanayaka AH, Wen TC, Deng CY, Pereira OL, Navathe S, Hawksworth DL, Fan XL, Dissanayake LS, Kuhnert E, Grossart HP, Thines M |title = Outline of Fungi and fungus-like taxa |journal=Mycosphere |year=2020 |volume=11 |issue=1 |pages=1060–1456 |url=http://www.mycosphere.org/pdf/MYCOSPHERE_11_1_8-1.pdf |issn=2077-7019 |doi=10.5943/mycosphere/11/1/8 |pmid= |doi-access=free }}</ref><ref name=OOF2022/><ref name=outline24/> |- style="vertical-align:top;" |style="width:50%;"| * Class [[Metchnikovellea]] ** Order [[Metchnikovellida]] *** Family [[Amphiacanthidae]] *** Family [[Metchnikovellidae]] * Class [[Microsporea]] ** Family [[Cougourdellidae]] ** Family [[Facilisporidae]] ** Family [[Heterovesiculidae]] ** Family [[Myosporidae]] ** Family [[Nadelsporidae]] ** Family [[Neonosemoidiidae]] ** Family [[Ordosporidae]] ** Family [[Pseudonosematidae]] ** Family [[Telomyxidae]] ** Family [[Toxoglugeidae]] ** Family [[Tubulinosematidae]] ** Subclass [[Haplophasea]] *** Order [[Chytridiopsida]] **** Family [[Chytridiopsidae]] **** Family [[Buxtehudeidae]] **** Family [[Enterocytozoonidae]] **** Family [[Burkeidae]] **** Family [[Hesseidae]] *** Order [[Glugeida]] **** Family [[Glugeidae]] **** Family [[Gurleyidae]] **** Family [[Encephalitozoonidae]] **** Family [[Abelsporidae]] **** Family [[Tuzetiidae]] **** Family [[Microfilidae]] **** Family [[Unikaryonidae]] ** Subclass [[Dihaplophasea]] *** Order [[Meiodihaplophasida]] **** Superfamily [[Thelohanioidea]] ***** Family [[Thelohaniidae]] ***** Family [[Duboscqiidae]] ***** Family [[Janacekiidae]] ***** Family [[Pereziidae]] ***** Family [[Striatosporidae]] ***** Family [[Cylindrosporidae]] **** Superfamily [[Burenelloidea]] ***** Family [[Burenellidae]] **** Superfamily [[Amblyosporoidea]] ***** Family [[Amblyosporidae]] *** Order [[Dissociodihaplophasida]] **** Superfamily [[Nosematoidea]] ***** Family [[Nosematidae]] ***** Family [[Ichthyosporidiidae]] ***** Family [[Caudosporidae]] ***** Family [[Pseudopleistophoridae]] ***** Family [[Mrazekiidae]] **** Superfamily [[Culicosporoidea]] ***** Family [[Culicosporidae]] ***** Family [[Culicosporellidae]] ***** Family [[Golbergiidae]] ***** Family [[Spragueidae]] **** Superfamily [[Ovavesiculoidea]] ***** Family [[Ovavesiculidae]] ***** Family [[Tetramicridae]] |style="width:50%;"| * Class [[Chytridiopsidea]] Issi 1980 – Moved out; see [[Rozellomycota]] * Class [[Rudimicrosporia]] Sprague – Moved out; see [[Rozellomycota]] * Class [[Microsporidea]] Delphy 1936 ex Levine & Corliss 1963 ** Family [[Abelsporidae]] Azevedo 1987 ** Family [[Areosporidae]] Stentiford et al. 2014 ** Family [[Burenellidae]] Jouvenaz & Hazard 1978 ** Family [[Burkeidae]] Sprague 1977 ** Family [[Cougourdellidae]] Poisson 1953 ** Family [[Cylindrosporidae]] Issi & Voronin 1986 ** Family [[Duboscqiidae]] Sprague 1977 ** Family [[Golbergiidae]] Issi 1986 ** Family [[Microfilidae]] Sprague, Becnel & Hazard 1992 ** Family [[Neonosemoidiidae]] Faye, Toguebaye & Bouix 1996 ** Family [[Pleistosporidiidae]] Codreanu-Balcesci & Codreanu 1982 ** Family [[Pseudopleistophoridae]] Sprague 1977 ** Family [[Striatosporidae]] Issi & Voronin 1986 ** Family [[Telomyxidae]] Leger & Hesse 1910 ** Family [[Toxoglugeidae]] Voronin 1993 ** Family [[Tuzetiidae]] Sprague, Tuzet & Maurand 1977 ** Order [[Amblyosporida]] Tokarev & Issi 2020 *** Family [[Amblyosporidae]] Weiser 1977 [Culicosporidae; Culicosporellidae] *** Family [[Caudosporidae]] Weiser 1958 [Flabelliformidae] *** Family [[Gurleyidae]] Sprague 1977 ** Order [[Neopereziida]] Tokarev & Issi 2020 *** Family [[Janacekiidae]] Issi et al. 1990 *** Family [[Berwaldiidae]] Simakova, Tokarev & Issi 2018a [Fibrillasporidae] *** Family [[Neopereziidae]] Voronin 1999 [Pseudonosematidae] *** Family [[Tubulinosematidae]] Franzen et al. 2005 ** Order [[Ovavesiculida]] Tokarev & Issi 2020 *** Family [[Ovavesiculidae]] Sprague, Becnel & Hazard 1992 ** Order [[Glugeida]] Issi 1986 *** Family [[Facilisporidae]] Jones, Prosperi-Porta & Kim 2012 *** Family [[Glugeidae]] Thélohan 1892 [Ichthyosporidiidae] *** Family [[Myosporidae]] Stentiford et al. 2010 *** Family [[Pereziidae]] Loubes et al. 1977 [Nadelsporidae] *** Family [[Pleistophoridae]] Doflein 1901 *** Family [[Spragueidae]] Weissenberg 1976 [Tetramicridae] *** Family [[Thelohaniidae]] Hazard & Oldacre 1975 [Coccosporidae] *** Family [[Unikaryonidae]] Sprague 1977 ** Order [[Nosematida]] Labbé 1899 *** Family [[Encephalitozoonidae]] Voronin 1989 *** Family [[Enterocytozoonidae]] Cali & Owen 1990 *** Family [[Heterovesiculidae]] Lange et al. 1995 *** Family [[Mrazekiidae]] Léger & Hesse 1922 [Rectisporidae] *** Family [[Nosematidae]] Labbe 1899 *** Family [[Ordosporidae]] Larsson, Ebert & Vávra 1997 |} |}

Corsaro 2022 adds (not accepted by Index Fungorum or 2024 ''Outline''):{{citation needed|reason=Please cite the originating text|date=April 2025}} * Order [[Paramicrosporidiales]] Corsaro 2022 ** Family [[Paramicrosporidiaceae]] Corsaro 2022 * Order [[Morellosporales]] Corsaro 2022 ** Family [[Mitosporidiaceae]] Corsaro 2022 ** Family [[Morellosporaceae]] Corsaro 2022 * Order [[Nucleophagales]] Corsaro 2022 ** Family [[Nucleophagaceae]] Corsaro 2022

In addition, there is the historical genus ''[[Microsporidium]]'' for holding species not otherwise classified.

==See also== * [[List of Microsporidian genera]] * ''[[Glugea]]'', a genus of microsporidia * ''[[Nosema apis]]'', a microsporidian parasite of bees

==References== {{notelist}} {{Reflist|refs=

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}}

== External links == {{Commons category|Microsporidia}} *{{Wikispecies-inline|Microsporidia}} *[http://www.biohealthbase.org/microsporidia BioHealthBase Bioinformatics Resource Center] Database of microspordia sequences and related information. *{{MeshName|Microsporidia}} {{Opisthokont protists}} {{Taxonbar|from1=Q132652|from2=Q54351344}} {{Authority control}}

[[Category:Microsporidia| ]]  [[Category:Fungus phyla]] [[Category:Fungi by classification]]