Group Group IV ((+)ssRNA) Genus Flavivirus | Family Flaviviridae | |
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Similar Powassan virus, Lujo virus, Duvenhage virus, Mokola virus, Banna virus | ||
Alkhurma virus (ALKV) is a member of the Flaviviridae virus family (class IV).
Contents
Taxonomy
It is closely related to the Kyasanur Forest disease virus (KFDV) with which it shares 89% nucleotide sequence homology. It appears that these viruses diverged 700 years ago.
Related viruses include Karshi virus and Farm Royal virus.
Clinical
This virus 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 six 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.
Epidemiology
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. There is evidence pointing to the sand tampan, Ornithodoros savignyi, as the vector.
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. 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.