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| __NOTOC__
| | #redirect [[Lassa virus]] |
| {{Lassa fever}}
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| {{CMG}}; {{AE}} {{Ammu}}
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| {{SK}} Lassa hemorrhagic fever; LHF
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| ==Overview==
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| Lassa fever is caused by the [[Lassa virus]], a member of the [[Arenaviridae]] family. It is an [[enveloped virus|enveloped]], [[single-stranded]], bisegmented [[RNA]] virus. The natural reservoir of Lassa virus is the Mastomys natalensis rodent (multimammate rat/mouse) that sheds the [[virus]] in [[urine]] and fecal droppings.
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| ==Causes==
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| ===Taxonomy===
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| * [[Viruses]]; [[ssRNA viruses]]; [[ssRNA negative-strand viruses]]; [[Arenaviridae]]; [[Mammarenavirus]] <ref>{{cite web | title = Taxonomy browser (Lassavirus) | url = http://www.ncbi.nlm.nih.gov/Taxonomy/Browser/wwwtax.cgi?mode=Info&id=11621&lvl=3&keep=1&srchmode=1&unlock&lin=s}}</ref>
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| ===Biology===
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| * Lassa virus belongs to Arenaviridae <ref name="NCCN">{{cite web | title = The Centers for Disease Control and Prevention | url =http://www.cdc.gov/vhf/virus-families/arenaviridae.html }}</ref>.
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| * The Arenaviridae are a family of [[viruses]] whose members are generally associated with rodent-transmitted diseases in [[humans]]. Each [[virus]] usually is associated with a particular [[rodent]] host species in which it is maintained.
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| ===Structure===
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| * Lassa virus is an enveloped, [[single-stranded]], bisegmented, ambisense [[RNA virus]].
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| ===Genome===
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| *Lassa virus genome is contained in two RNA segments, each of which encodes 2 viral proteins (total 4 viral proteins)<ref name="pmid10615121">{{cite journal| author=| title=Genome:The autobiography of a species in 23 chapters | journal=Nat Genet | year= 2000 | volume= 24 | issue= 1 | pages= 21 | pmid=10615121 | doi=10.1038/71638 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10615121 }} </ref><ref name="pmid17143722">{{cite journal| author=Moshkoff DA, Salvato MS, Lukashevich IS| title=Molecular characterization of a reassortant virus derived from Lassa and Mopeia viruses. | journal=Virus Genes | year= 2007 | volume= 34 | issue= 2 | pages= 169-76 | pmid=17143722 | doi=10.1007/s11262-006-0050-3 | pmc=PMC1892610 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=17143722 }} </ref>
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| **The large segment encodes RNA polymerase (L) and a small zinc-binding protein (Z) that regulates transcription and replication<ref name="pmid11533204">{{cite journal| author=Cornu TI, de la Torre JC| title=RING finger Z protein of lymphocytic choriomeningitis virus (LCMV) inhibits transcription and RNA replication of an LCMV S-segment minigenome. | journal=J Virol | year= 2001 | volume= 75 | issue= 19 | pages= 9415-26 | pmid=11533204 | doi=10.1128/JVI.75.19.9415-9426.2001 | pmc=PMC114509 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11533204 }} </ref><ref name="pmid9281522">{{cite journal| author=Djavani M, Lukashevich IS, Sanchez A, Nichol ST, Salvato MS| title=Completion of the Lassa fever virus sequence and identification of a RING finger open reading frame at the L RNA 5' End. | journal=Virology | year= 1997 | volume= 235 | issue= 2 | pages= 414-8 | pmid=9281522 | doi=10.1006/viro.1997.8722 | pmc= | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=9281522 }} </ref>
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| **The small segment encodes the [[nucleoprotein]] (NP) and the surface [[glycoprotein precursor]] ([[GP]] or viral spike). The GP protein is cleaved into the [[envelope]] [[glycoproteins]], [[GP1]] and [[GP2]], that bind to the alpha-dystroglycan [[receptor]] and mediate [[host]] cell entry<ref name="pmid11119613">{{cite journal| author=Smelt SC, Borrow P, Kunz S, Cao W, Tishon A, Lewicki H et al.| title=Differences in affinity of binding of lymphocytic choriomeningitis virus strains to the cellular receptor alpha-dystroglycan correlate with viral tropism and disease kinetics. | journal=J Virol | year= 2001 | volume= 75 | issue= 1 | pages= 448-57 | pmid=11119613 | doi=10.1128/JVI.75.1.448-457.2001 | pmc=PMC113937 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=11119613 }} </ref>
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| *[[Nucleotide]] studies of the [[genome]] have shown that Lassa has four lineages: Three in Nigeria and a fourth in Guinea, Liberia, and Sierra Leone. The Nigerian strains are thought to be ancestral to the others.<ref name="pmid10888638">{{cite journal| author=Bowen MD, Rollin PE, Ksiazek TG, Hustad HL, Bausch DG, Demby AH et al.| title=Genetic diversity among Lassa virus strains. | journal=J Virol | year= 2000 | volume= 74 | issue= 15 | pages= 6992-7004 | pmid=10888638 | doi= | pmc=PMC112216 | url=http://www.ncbi.nlm.nih.gov/entrez/eutils/elink.fcgi?dbfrom=pubmed&tool=sumsearch.org/cite&retmode=ref&cmd=prlinks&id=10888638 }} </ref>.
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| ==Natural Reservoir==
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| *The most common natural [[reservoir]] of Lassa virus is the [[rodent]], Mastomys natalensis. Mastomys natalensis is commonly known as the “multimammate rat/mouse” due to the female’s multiple and prominent mammary glands.
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| *The mastomys rodents are abundant in the Savannas and forests of West, Central, and East Africa.
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| *Once infected, the rodent is able to [[excrete]] the [[virus]] in the [[urine]] and feces for an extended time period. Mastomys rodents breed frequently, produce large numbers of offspring, and commonly inhabit human homes with food storage. All of these factors contribute to the relatively efficient spread of Lassa virus from [[infected]] [[rodents]] to [[humans]].
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| {|
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| [[File:Mastomys natalensis.jpg|thumb|400 px|Mastomys natalensis or the natal multimammate mouse.<ref name="Wikipedia Natal multimammate mouse">{{Cite web | title = Wikipedia Natal multimammate mouse| url = http://en.wikipedia.org/wiki/Natal_multimammate_mouse}}</ref>]]
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| | style="width: 300px" |
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| | [[File:Mastomys natalensis mammary.jpg|thumb|400 px|Mastomys natalensis is commonly known as the “multimammate rat” due to the female’s multiple and prominent mammary glands.<ref name="Wikipedia Natal multimammate mouse">{{Cite web | title = Wikipedia Natal multimammate mouse| url = http://en.wikipedia.org/wiki/Natal_multimammate_mouse}}</ref>]]
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| |}
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| ==Gallery==
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| The images below display key features of the Lassa virus.
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| <gallery>
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| Image:Micro lassa 01.jpg|This transmission electron micrograph (TEM) demonstrates Lassa virus virions adjacent to host cell debris.<SMALL><SMALL>''[http://phil.cdc.gov/phil/details.asp Retrieved from the Public Health Image Library (PHIL), Centers for Disease Control and Prevention.]''<ref name="PHIL">{{Cite web | title = Public Health Image Library (PHIL), Centers for Disease Control and Prevention | url = http://phil.cdc.gov/phil/details.asp/}}</ref></SMALL></SMALL>
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| Image:Lassa virions.jpg|This highly magnified transmission electron micrograph (TEM) demonstrates ultrastructural details of 3 Lassa virus virions.<SMALL><SMALL>''[http://phil.cdc.gov/phil/details.asp Retrieved from the Public Health Image Library (PHIL), Centers for Disease Control and Prevention.]''<ref name="PHIL">{{Cite web | title = Public Health Image Library (PHIL), Centers for Disease Control and Prevention | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL></SMALL>
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| Image:Arenavirus01.jpeg|This transmission electron micrograph depicted eight virions (viral particles) of an Arenavirus.<SMALL><SMALL>''[http://phil.cdc.gov/phil/details.asp Retrieved from the Public Health Image Library (PHIL), Centers for Disease Control and Prevention.]''<ref name="PHIL">{{Cite web | title = Public Health Image Library (PHIL), Centers for Disease Control and Prevention | url = http://phil.cdc.gov/phil/details.asp}}</ref></SMALL></SMALL></gallery>
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| ==References==
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| {{Reflist|2}}
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| [[Category:Disease]]
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| [[Category:Viral diseases]]
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| [[Category:Viruses]]
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| [[Category:Zoonoses]]
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| [[Category:Hemorrhagic fevers]]
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| [[Category:Tropical disease]]
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| [[Category:Infectious disease]]
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