Marburg virus[1] is a hemorrhagic fever virus of the Filoviridae family of viruses and a member of the species Marburg marburgvirus, genus Marburgvirus. Marburg virus (MARV) causes Marburg virus disease in humans and other primates, a form of viral hemorrhagic fever.[2] The virus is considered to be extremely dangerous. The World Health Organization (WHO) rates it as a Risk Group 4 Pathogen (requiring biosafety level 4-equivalent containment).[3] In the United States, the NIH/National Institute of Allergy and Infectious Diseases ranks it as a Category A Priority Pathogen[4] and the Centers for Disease Control and Preventionlists it as a Category A Bioterrorism Agent.[5] It is also listed as a biological agent for export control by the Australia Group.[6]
The disease can cause bleeding (haemorrhage), fever, and other symptoms similar to Ebola. However, Marburg virus is not the same as Ebola, although similar. Actual treatment of the virus after infection is not possible, but early, professional treatment of symptoms like dehydration considerably increases survival chances.[7]
Marburg virus was first described in 1967.[11] It was discovered that year during a set of outbreaks of Marburg virus disease in the German cities of Marburg and Frankfurt and the Yugoslav capital Belgrade. Laboratory workers were exposed to tissues of infected grivet monkeys(the African green monkey, Chlorocebus aethiops) at the Behringwerke, a major industrial plant in Marburg which was then part of Hoechst, and later part of CSL Behring. During the outbreaks, thirty-one people became infected and seven of them died.[12]
Like all filoviruses, marburgvirions are filamentous particles that may appear in the shape of a shepherd's crook or in the shape of a "U" or a "6", and they may be coiled, toroid, or branched.[17] Marburgvirions are generally 80 nm in width, but vary somewhat in length. In general, the median particle length of marburgviruses ranges from 795 to 828 nm (in contrast to ebolavirions, whose median particle length was measured to be 974–1,086 nm ), but particles as long as 14,000 nm have been detected in tissue culture.[18]
Marburgvirions consist of seven structural proteins. At the center is the helical ribonucleocapsid, which consists of the genomic RNA wrapped around a polymer of nucleoproteins (NP). Associated with the ribonucleoprotein is the RNA-dependent RNA polymerase (L) with the polymerase cofactor (VP35) and a transcription activator (VP30). The ribonucleoprotein is embedded in a matrix, formed by the major (VP40) and minor (VP24) matrix proteins. These particles are surrounded by a lipid membranederived from the host cell membrane. The membrane anchors a glycoprotein (GP1,2) that projects 7 to 10 nm spikes away from its surface. While nearly identical to ebolavirions in structure, marburgvirions are antigenically distinct.[citation needed]
Niemann–Pick C1 (NPC1) cholesterol transporter protein appears to be essential for infection with both Ebola and Marburg virus. Two independent studies reported in the same issue of Nature showed that Ebola virus cell entry and replication requires NPC1.[19][20] When cells from patients lacking NPC1 were exposed to Ebola virus in the laboratory, the cells survived and appeared immune to the virus, further indicating that Ebola relies on NPC1 to enter cells. This might imply that genetic mutations in the NPC1 gene in humans could make some people resistant to one of the deadliest known viruses affecting humans. The same studies described similar results with Marburg virus, showing that it also needs NPC1 to enter cells.[19][20] Furthermore, NPC1 was shown to be critical to filovirus entry because it mediates infection by binding directly to the viral envelope glycoprotein[20] and that the second lysosomal domain of NPC1 mediates this binding.[21]
In one of the original studies, a small molecule was shown to inhibit Ebola virus infection by preventing the virus glycoprotein from binding to NPC1.[20][22] In the other study, mice that were heterozygous for NPC1 were shown to be protected from lethal challenge with mouse-adapted Ebola virus.[19]
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In 2009, expanded clinical trials of an Ebola and Marburg vaccine began in Kampala, Uganda.[8][9]
Virus classification | |
|---|---|
| (unranked): | Virus |
| Realm: | Riboviria |
| Kingdom: | Orthornavirae |
| Phylum: | Negarnaviricota |
| Class: | Monjiviricetes |
| Order: | Mononegavirales |
| Family: | Filoviridae |
| Genus: | Marburgvirus |
| Species: | |
| Virus: | Marburg virus |
https://en.wikipedia.org/wiki/Marburg_virus
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