Hipah Virus

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Henipavirus
From Wikipedia, the free encyclopedia
Henipaviruses |
Virus classification |
Group: | Group V ((-)ssRNA) |
Order: | Mononegavirales |
Family: | Paramyxoviridae |
Genus: | Henipavirus |
Type species |
Hendra virus |
Species |
Cedar virus
Hendra virus
Nipah virus |
Henipavirus is a genus ofthe family Paramyxoviridae, order Mononegavirales containing three established species: Hendra virus, Nipah virus and Cedar Virus. The henipaviruses are naturally harboured by Pteropid fruit bats (flying foxes) and some microbat species.[1]Henipavirus is characterised by a large genome, a wide host range, and their recent emergence as zoonotic pathogens capable of causing illness and death in domesticanimals and humans.[2]
In 2009, RNA sequences of three novel viruses in phylogenetic relationship to known Henipaviruses were detected in Eidolon helvum (the African Straw-coloured fruit bat) in Ghana. The finding of these novel putative Henipaviruses outside Australia and Asia indicates that the region of potential endemicity of Henipaviruses extends to Africa.[3]
Contents  [hide]  * 1 Virus structure *2 Genome structure * 3 Hendra virus * 3.1 Emergence * 3.2 Australian outbreaks * 3.3 Events of June – August 2011 * 3.4 Prevention, detection and treatment * 3.5 Pathology * 4 Nipah virus * 4.1 Emergence * 4.2 Outbreaks * 4.3 Pathology * 4.4 In popular culture * 5 Cedar virus * 5.1 Emergence * 6 Causes of emergence * 7 See also * 8 References* 9 External links |
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[edit]Virus structure

Structure of henipaviruses

The henipavirus genome (3’ to 5’ orientation) and products of the P gene
Henipaviruses are pleomorphic (variably shaped), ranging in size from 40 to 600 nm in diameter.[4] They possess a lipid membrane overlying a shell of viral matrix protein. At the core is a singlehelical strand of genomic RNAtightly bound to N (nucleocapsid) protein and associated with the L (large) and P (phosphoprotein) proteins which provide RNA polymerase activity during replication.
Embedded within the lipid membrane are spikes of F (fusion) protein trimers and G (attachment) protein tetramers. The function of the G protein is to attach the virus to the surface of a host cellvia EFNB2, a highly conserved protein present in many mammals.[5][6] The F protein fuses the viral membrane with the host cell membrane, releasing the virion contents into the cell. It also causes infected cells to fuse with neighbouring cells to form large, multinucleated syncytia.
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[edit]Genome structure
As with all viruses inthe Mononegavirales order, the Hendra virus and Nipah virus genomes are non-segmented, single-stranded negative-sense RNA. Both genomes are 18.2 kb in size and contain six genes corresponding to six structural proteins.[7]
In common with other members of the Paramyxovirinae subfamily, the number of nucleotides in the henipavirus genome is a multiple of six, consistent with what is known as the 'rule of six'.[8] Deviationfrom the rule of six, through mutation or incomplete genome synthesis, leads to inefficient viral replication, probably due to structural constraints imposed by the binding between the RNA and the N protein.
Henipaviruses employ an unusual process called RNA editing to generate multiple proteins from a single gene. The specific process in henipaviruses involves the insertion ofextra guanosine residues into the P gene mRNA prior totranslation. The number of residues added determines whether the P, V or W proteins are synthesised. The functions of the V and W proteins are unknown, but they may be involved in disrupting host antiviral mechanisms.
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[edit]Hendra virus
[edit]Emergence
Hendra virus (originally Equine morbillivirus)...