Microsporidiosis 3112814 168912755 2007-11-03T09:21:27Z Mimihitam 4383153 {{Infobox_Disease | Name = {{PAGENAME}} | Image = | Caption = | DiseasesDB = 31870 | ICD10 = {{ICD10|B|60|8|b|50}} | ICD9 = {{ICD9|136.8}} | ICDO = | OMIM = | MedlinePlus = | eMedicineSubj = med | eMedicineTopic = 1469 | MeshID = D016881 | }} '''Microspridiosis''' is an opportunistic intestinal infection that causes [[diarrhea]] and wasting in [[immunocompromised]] individuals ([[HIV]], for example). It results from different species of [[microsporidia]], a group of [[protozoa]]l parasites. In [[HIV]] infected individuals, microsporidiosis generally occurs when [[CD4]]+ [[T cell]] counts fall below 100. ==Causative agents== At least 14 microsporidian species have been recognized as human [[pathogen]]s, spread across eight genera: * ''[[Brachiola]]'' ** ''B. algerae'', ''B. connori'', ''B. vesicularum'' * ''[[Encephalitozoon]]'' ** ''E. cuniculi'', ''E. hellem'', ''E. intestinalis'' * Enterocytozoon ** ''E. bieneusi'' * ''[[Microsporidium]]'' ** ''M. ceylonensis'', ''M. africanum'' * ''[[Nosema]]'' ** ''N. ocularum'' * ''[[Pleistophora]] sp.'' * ''[[Trachipleistophora]]'' ** ''T. hominis'', ''T. anthropophthera'' * ''[[Vittaforma]]'' ** ''V. corneae.'' ==Life cycle== [[Image:Microsporidiosis 01.png|thumb|right|Life cycle of the various organisms that cause microsporidiosis.]] ''(Coded to [[:Image:Microsporidiosis 01.png|image]] at right).'' # The infective form of microsporidia is the resistant [[spore]] and it can survive for an exteneded period of time in the environment. # The spore extrudes its polar tubule and infects the host cell. # The spore injects the infective [[sporoplasm]] into the [[eukaryotic]] host cell through the polar tubule. # Inside the cell, the sporoplasm undergoes extensive multiplication either by [[merogony]] (binary fission) or [[schizogony]] (multiple fission). # This development can occur either in direct contact with the host cell [[cytoplasm]] (''[[Encephalitozoon bieneusi|E. bieneusi]]'') or inside a [[vacuole]] called a [[parasitophorous]] vacuole (''[[Encephalitozoon intestinalis|E. intestinalis]]''). Either free in the cytoplasm or inside a parasitophorous vacuole, microsporidia develop by [[sporogony]] to mature spores. # During sporogony, a thick wall is formed around the spore, which provides resistance to adverse environmental conditions. When the spores increase in number and completely fill the host cell cytoplasm, the cell membrane is disrupted and releases the spores to the surroundings. # These free mature spores can infect new cells thus continuing the cycle. ==External links== * CDC's [http://www.dpd.cdc.gov/dpdx/HTML/Microsporidiosis.htm microsporidiosis] info page. {{Protozoal diseases}} [[Category:Digestive diseases]] [[id:Mikrosporidiosis]]