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| __NOTOC__
| | #REDIRECT[[Hepatitis A virus]] |
| {{Hepatitis A}}
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| {{CMG}}; {{AE}} {{JS}}
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| ==Overview==
| | [[Category:Emergency mdicine]] |
| [[Hepatitis A virus]] ([[HAV]]) is a 27 nm, [[Viral envelope|non-enveloped]], icosahedral, [[Positive-sense ssRNA virus|ssRNA virus]] with a single [[serovar]]. Its [[genome]] is encoded in 7474 [[nucleotides]] and the [[virus]] has [[tropism]] for the [[hepatocytes]], where it [[viral replication|replicates]]. Humans are the only [[natural reservoir]] of the [[virus]].
| | [[Category:Disease]] |
| | | [[Category:Up-To-Date]] |
| ==Taxonomy==
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| [[Viruses]]; [[ssRNA]] [[viruses]]; [[Positive-sense ssRNA virus|ssRNA virus]]; positive-strand viruses; Picornavirales; [[Picornaviridae]]; [[Hepatovirus]]
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| ==Biology==
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| {| style="float: right;"
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| | [[File:HapatitisA.jpeg|200px|thumb|none|Electron micrograph of the Hepatitis A virus (HAV), an RNA virus that can survive up to a month at room temperature. <SMALL>Courtesy: ''[http://phil.cdc.gov/phil/home.asp Public Health Image Library (PHIL), Centers for Disease Control and Prevention (CDC)]''<ref>{{Cite web | title = http://phil.cdc.gov/phil/details.asp | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL>]]
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| |}
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| [[Hepatitis A virus]] ([[HAV]]) is a 27 nm, [[Viral envelope|non-enveloped]], icosahedral, [[Positive-sense ssRNA virus|ssRNA virus]] with a single [[serovar]]. So far, 4 different [[genotype]]s have been identified in [[hepatitis A virus]]es, all belonging to the same [[serotype]].<ref name="pmid1335657">{{cite journal| author=Lemon SM, Jansen RW, Brown EA| title=Genetic, antigenic and biological differences between strains of hepatitis A virus. | journal=Vaccine | year= 1992 | volume= 10 Suppl 1 | issue= | pages= S40-4 | pmid=1335657 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=1335657 }} </ref>
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| [[HAV]] has no lipid envelope and is stable when excreted from the infected liver to the bile to enter the gastrointestinal tract. It has been found to survive in experimentally contaminated fresh water, seawater, wastewater, soils, marine sediment, live oysters, and creme-filled cookies.<ref name=WHO>{{cite web | title = Hepatitis A | url = http://www.who.int/csr/disease/hepatitis/HepatitisA_whocdscsredc2000_7.pdf }}</ref>
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| HAV is extremely resistant to degradation by environmental conditions, a property that allows its maintenance and spread within populations.<ref name=WHO>{{cite web | title = Hepatitis A | url = http://www.who.int/csr/disease/hepatitis/HepatitisA_whocdscsredc2000_7.pdf }}</ref>
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| ===Genome===
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| The [[HAV]] [[genome]] is encoded in 7474 [[nucleotides]], which are divided into three regions:
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| * 5' untranslated region, with 742 [[nucleotides]]
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| * Single [[reading frame]] encoding a 2227 [[amino acid]] [[polypeptide]], with 6681 [[nucleotides]]
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| * 3' noncoding region, with 63 [[nucleotides]]
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| The [[reading frame]] encodes a [[polypeptide]] that is processed by a [[viral]] [[protease]]. This process takes place cotranslationally, and leads to the formation of:
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| * Four structural [[proteins]]
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| * Seven nonstructural [[proteins]]
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| ==Tropism==
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| Similarly to other [[hepatitis]] viruses, the [[hepatitis A virus]] shows [[tropism]] for the [[liver cells]]. The [[hepatocytes]] represent the predominant site for [[viral replication]].<ref name="pmid9265900">{{cite journal| author=Lemon SM| title=Type A viral hepatitis: epidemiology, diagnosis, and prevention. | journal=Clin Chem | year= 1997 | volume= 43 | issue= 8 Pt 2 | pages= 1494-9 | pmid=9265900 | doi= | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9265900 }} </ref>
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| ==Natural Reservoir==
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| * Humans are the only [[natural reservoir]] of the [[virus]].<ref name=CDC>{{cite web | title = Hepatitis A | url = http://www.cdc.gov/vaccines/pubs/pinkbook/hepa.html }}</ref>
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| * There are no insect or animal vectors.<ref name=CDC>{{cite web | title = Hepatitis A | url = http://www.cdc.gov/vaccines/pubs/pinkbook/hepa.html }}</ref>
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| * A chronic [[HAV]] carrier state has not been reported.<ref name=CDC>{{cite web | title = Hepatitis A | url = http://www.cdc.gov/vaccines/pubs/pinkbook/hepa.html }}</ref>
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| ==References==
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| {{Reflist|2}}
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| [[Category:Foodborne illnesses]] | |
| [[Category:hepatitis|A]] | |
| [[Category:Picornaviruses]] | |
| [[Category:Viral diseases]]
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| [[Category:Mature chapter]]
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| [[Category:Infectious disease]] | | [[Category:Infectious disease]] |
| [[Category:Disease]] | | [[Category:Hepatology]] |
| | | [[Category:Gastroenterology]] |
| {{WH}}
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| {{WS}}
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