Alkhurma virus
| Alkhurma virus | |
|---|---|
| Virus classification | |
| Group: | Group IV ((+)ssRNA) |
| Family: | Flaviviridae |
| Genus: | Flavivirus |
| Species | |
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Alkhurma virus |
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Alkhurma virus (ALKV) is a member of the Flaviviridae virus family (class IV).
Contents |
Virology [edit]
The virus has a positive sense single stranded RNA genome and replicates in the cytoplasm of the infected host cell. The virus genome is able to mimic mRNA in host cells and so can use some of the host cells enzymes and machinery for its own gene expression, the virus encodes a single polyprotein which is cleaved to form mature proteins.
It is closely related to the Kyasanur Forest disease virus (KFDV) with which it shares 89% nucleotide sequence homology.[1] It appears that these viruses diverged 700 years ago.[2]
Related viruses include Karshi virus and Farm Royal virus.
Clinical [edit]
This virus[3] was first isolated in Saudi Arabia in the 1990s and since then there have been 24 reported cases, mainly occurring among butchers, with the case fatality-rate above 30%. It was first discovered in the blood of 6 male butchers, aged 24–39 years, in Jeddah, Saudi Arabia in November and December 1995. It causes a type of tick-borne hemorrhagic fever with the symptoms including fever, headache, joint pain, muscle pain, vomiting and thrombocytopenia which lead to hemorrhagic fever and encephalitis which can result in death.[4]
Epidemiology [edit]
Camels and sheep are the natural hosts of this virus but it is not yet known if other mammals are also involved in its life cycle. There appears to be more than one possible route of transmission seen in people who have become infected with this virus. These are a bite by an infected tick, ingestion of unpasteurised camel milk or entry via a skin wound.
The geographic distribution of the virus may extend beyond Saudi Arabia; it has been imported to other countries in travelers from an area not known to be endemic for the disease.[5] A Saudi study published in December 2011 provided evidence for a wider range of endemicity than previously reported, with most seropositive persons originating from Tabouk and Eastern Directorates.[6]
References [edit]
- ^ Deresinski S (2010) Alkhurma Hemorrhagic Fever Virus: An Emerging Pathogen. Clinical Infectious Diseases 51(4): iv, http://cid.oxfordjournals.org/content/51/4/iv.full.
- ^ Dodd KA, Bird BH, Khristova ML, Albariño CG, Carroll SA, Comer JA, Erickson BR, Rollin PE, Nichol ST (2011) Ancient ancestry of KFDV and AHFV revealed by complete genome analyses of viruses isolated from ticks and mammalian hosts. PLoS Negl Trop Dis 5(10):e1352.
- ^ Sometimes misidentified as "Al-Khumra" virus—"It’s Al-Khurma, not Al-Khumra, says official", The Saudi Gazette, 13 Jan 2010, http://www.saudigazette.com.sa/index.cfm?method=home.regcon&contentID=2010011360023.
- ^ Zaki AM (1997). "Isolation of a flavivirus related to the tick-borne encephalitis complex from human cases in Saudi Arabia". Trans. R. Soc. Trop. Med. Hyg. 91 (2): 179–81. doi:10.1016/S0035-9203(97)90215-7. PMID 9196762.
- ^ Carletti F, Castilletti C, Di Caro A, Capobianchi MR, Nisii C, Suter F, et al. (2010) Alkhurma hemorrhagic fever in travelers returning from Egypt, 2010. Emerging Infectious Diseases, December 2010, http://dx.doi.org/10.3201/eid1612101092.
- ^ Memish ZA, Albarrak A, Almazroa MA, Al-Omar I, Alhakeem R, Assiri A, et al. Seroprevalence of Alkhurma and other hemorrhagic fever viruses, Saudi Arabia. Emerging Infectious Diseases, December 2011, http://dx.doi.org/10.3201/eid1712.110658.
Further reading [edit]
- Charrel RN, Zaki AM, Fakeeh M et al. (2005). "Low diversity of Alkhurma hemorrhagic fever virus, Saudi Arabia, 1994-1999". Emerging Infect. Dis. 11 (5): 683–8. PMID 15890119.
- Charrel RN, Zaki AM, Attoui H et al. (2001). "Complete coding sequence of the Alkhurma virus, a tick-borne flavivirus causing severe hemorrhagic fever in humans in Saudi Arabia". Biochem. Biophys. Res. Commun. 287 (2): 455–61. doi:10.1006/bbrc.2001.5610. PMID 11554750.
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