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| __NOTOC__
| | #REDIRECT[[Ebola virus]] |
| <div style="float: right;">
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| {{Taxobox
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| | name = Ebola virus
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| | image = Ebola_virus.jpg
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| | image_width = 100px
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| | caption = An [[electron microscope|electron micrograph]] of an Ebola virus
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| | virus_group = V
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| | ordo = ''[[Mononegavirales]]''
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| | familia = ''[[Filovirus]]''
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| | genus = ''Ebolavirus''
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| | type_species = ''Zaïre Ebolavirus''
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| | subdivision_ranks = Species
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| | subdivision = ''[[Ebola Reston|Reston Ebolavirus]]''<br />''Sudan Ebolavirus''<br />''Ivory Coast Ebolavirus''<br />''Bundibugyo Ebolavirus''
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| }}</div>
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| {{Ebola}}
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| {{CMG}}
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| ==Overview==
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| Ebola infection is caused by a [[virus]] that belongs to the family [[Filoviridae]]. Four [[viral]] subtypes have been reported to cause clinical illness in humans: Bundibugyo ebolavirus, Sudan ebolavirus, Tai Forest ebolavirus, and Zaire ebolavirus. The human disease has so far been limited to parts of Africa. A very small number of people in the United States and in the Philippines were infected with the fifth type of the [[virus]], known as Reston ebolavirus, and did not develop any signs of disease.
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| ==Taxonomy==
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| '''''Viruses; ssRNA viruses; ssRNA negative-strand viruses; Mononegavirales; Filoviridae; Ebolavirus'''''<ref>{{cite web | title = Taxonomy browser (Ebolavirus) | url = http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Tree&id=186536&lvl=3&lin=f&keep=1&srchmode=1&unlock}}</ref>
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| * Ebolavirus
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| :* Bundibugyo ebolavirus
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| :* Reston ebolavirus
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| ::* Reston ebolavirus - Reston
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| ::* Reston ebolavirus - Reston (1989)
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| ::* Reston ebolavirus - Siena/Philippine-92
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| :* Sudan ebolavirus
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| ::* Sudan ebolavirus - Boniface (1976)
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| ::* Sudan ebolavirus - Maleo (1979)
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| ::* Sudan ebolavirus - Nakisamata
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| ::* Sudan ebolavirus - Uganda (2000)
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| :* Tai Forest ebolavirus
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| ::* Tai Forest virus - Côte d’Ivoire, Côte d’Ivoire, 1994
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| :* Zaire ebolavirus
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| ::* Ebola virus - Mayinga, Zaire, 1976
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| ::* Zaire ebolavirus - Eckron (Zaire, 1976)
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| ::* Zaire ebolavirus - Gabon (1994-1997)
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| ::* Zaire ebolavirus - Zaire (1995)
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| :* Unclassified Ebolavirus
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| ::* Ebola virus Yambio0401
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| ::* Ebola virus Yambio0402
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| ::* Ebola virus Yambio0403
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| ::* Ebola virus sp.
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| ==Biology==
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| Ebola infection is caused by a [[virus]] that belongs to the family [[Filoviridae]]. Four [[viral]] subtypes have been reported to cause clinical illness in humans: Bundibugyo ebolavirus, Sudan ebolavirus, Tai Forest ebolavirus, and Zaire ebolavirus. The human disease has so far been limited to parts of Africa. A very small number of people in the United States and in the Philippines were infected with the fifth type of the [[virus]], known as Reston ebolavirus, and did not develop any signs of disease. The virus can be passed to humans from infected animals and animal materials. Ebola can also be spread among humans by close contact with infected body fluids or by infected needles.
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| ==Structure==
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| ===Size and Shape===
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| [[Electron microscope|Electron micrographs]] of members of ''Ebola virus'' show them to have the characteristic thread-like structure of a [[Filoviridae|filovirus]].<ref name="Klenk2004">{{cite book |title=Ebola and Marburg Viruses, Molecular and Cellular Biology |last=Klenk |first=Hans-Dieter |authorlink= |coauthors=Feldmann, Heinz |year=2004 |publisher=Horizon Bioscience |location=Wymondham, Norfolk |isbn=0954523237 |pages= }}</ref> EBOV VP30 is around 288 amino acids long.<ref name="Klenk2004" /> The virions are tubular and variable in shape and may appear as a "U", "6", coiled, circular, or branched shape, however, laboratory purification techniques, such as [[centrifugation]], may contribute to the various shapes.<ref name="Klenk2004" /> Virions are generally 80 [[nanometer|nm]] in diameter.<ref name="Klenk2004" /> They are variable in length, and can be up to 1400 nm long. On average, however, the length of a typical [[virion|Ebola virus]] is closer to 1000 nm. In the center of the virion is a structure called nucleocapsid, which is formed by the helically wound viral genomic RNA complexed with the proteins ''NP, VP35, VP30'' and ''L''. It has a diameter of 40 – 50 nm and contains a central channel of 20–30 nm in diameter. Virally encoded [[glycoprotein]] (GP) spikes 10 nm long and 10 nm apart are present on the outer [[viral envelope]] of the virion, which is derived from the host cell membrane. Between envelope and nucleocapsid, in the so-called matrix space, the viral proteins VP40 and VP24 are located. | |
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| ===Genome===
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| Each virion contains one minor molecule of linear, single-stranded, [[Sense (molecular biology)|negative-sense]] RNA, totaling 18959 to 18961 nucleotides in length. The 3′ terminus is not polyadenylated and the 5′ end is not capped. It was found that 472 nucleotides from the 3' end and 731 nucleotides from the 5' end were sufficient for replication.<ref name="Klenk2004" /> It codes for seven structural proteins and one non-structural protein. The gene order is 3′ - leader - NP - VP35 - VP40 - GP/sGP - VP30 - VP24 - L - trailer - 5′; with the leader and trailer being non-transcribed regions which carry important signals to control transcription, replication and packaging of the viral genomes into new virions. The genomic material by itself is not infectious, because viral proteins, among them the RNA-dependent RNA polymerase, are necessary to transcribe the viral genome into mRNAs, as well as for replication of the viral genome.
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| ===Life Cycle===
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| * Virus attaches to host receptors through the GP (glycoprotein) surface [[peplomer]] and is endocytosed into vesicles in the host cell.
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| * Fusion of virus membrane with the vesicle membrane occurs; nucleocapsid is released into the cytoplasm.
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| * The encapsidated, negative-sense genomic ssRNA is used as a template for the synthesis (3' - 5') of polyadenylated, monocistronic mRNAs.
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| * Translation of the mRNA into viral proteins occurs using the host cell's machinery.
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| * Post-translational processing of viral proteins occurs. GP0 (glycoprotein precursor) is cleaved to GP1 and GP2, which are heavily glycosylated. These two molecules assemble, first into heterodimers, and then into trimers to give the surface peplomers. SGP (secreted glycoprotein) precursor is cleaved to SGP and delta peptide, both of which are released from the cell.
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| * As viral protein levels rise, a switch occurs from translation to replication. Using the negative-sense genomic RNA as a template, a complementary +ssRNA is synthesized; this is then used as a template for the synthesis of new genomic (-)ssRNA, which is rapidly encapsidated.
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| * The newly-formed nucleocapsides and envelope proteins associate at the host cell's plasma membrane; budding occurs, and the virions are released
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| Scientists have identified four types of the Ebola virus. Three have been reported to cause [[disease]] in humans: Ebola-Zaire virus, Ebola-Sudan virus, and Ebola-Ivory Coast virus. The human disease has so far been limited to parts of Africa. A very small number of people in the United States who were infected with the fourth type of the virus, known as Ebola Reston, did not develop any signs of disease. The disease can be passed to humans from infected animals and animal materials. Ebola can also be spread between humans by close contact with infected bodily fluids or through infected [[needles]] in the hospital.
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| ==References==
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| {{reflist|2}}
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| [[Category:Biological weapons]]
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| [[Category:Disease]]
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| [[Category:Hemorrhagic fevers]]
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| [[Category:Infectious disease]]
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| [[Category:Mononegavirales]]
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| [[Category:Viral diseases]]
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| [[Category:Zoonoses]]
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