Alkhurma virus
Encyclopedia
Alkhurma virus is a member of the Flaviviridae
virus family (class IV).
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.
in the 1990s and since then there have been 24 reported cases, mainly occurring among butcher
s, 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.
s and sheep are the natural hosts of this virus but it is not yet known if other mammal
s 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.
Flaviviridae
The Flaviviridae are a family of viruses that are primarily spread through arthropod vectors . The family gets its name from Yellow Fever virus, a type virus of Flaviviridae; flavus means yellow in Latin...
virus family (class IV).
Virology
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. 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 ArabiaSaudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...
in the 1990s and since then there have been 24 reported cases, mainly occurring among butcher
Butcher
A butcher is a person who may slaughter animals, dress their flesh, sell their meat or any combination of these three tasks. They may prepare standard cuts of meat, poultry, fish and shellfish for sale in retail or wholesale food establishments...
s, 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
Fever
Fever is a common medical sign characterized by an elevation of temperature above the normal range of due to an increase in the body temperature regulatory set-point. This increase in set-point triggers increased muscle tone and shivering.As a person's temperature increases, there is, in...
, headache
Headache
A headache or cephalalgia is pain anywhere in the region of the head or neck. It can be a symptom of a number of different conditions of the head and neck. The brain tissue itself is not sensitive to pain because it lacks pain receptors. Rather, the pain is caused by disturbance of the...
, joint pain, muscle pain, vomiting and thrombocytopenia which lead to hemorrhagic fever and encephalitis
Encephalitis
Encephalitis is an acute inflammation of the brain. Encephalitis with meningitis is known as meningoencephalitis. Symptoms include headache, fever, confusion, drowsiness, and fatigue...
which can result in death.
Epidemiology
CamelCamel
A camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
s and sheep are the natural hosts of this virus but it is not yet known if other mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
s 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
Milk
Milk is a white liquid produced by the mammary glands of mammals. It is the primary source of nutrition for young mammals before they are able to digest other types of food. Early-lactation milk contains colostrum, which carries the mother's antibodies to the baby and can reduce the risk of many...
or entry via a skin wound.
The geographic distribution of the virus may extend beyond Saudi Arabia
Saudi Arabia
The Kingdom of Saudi Arabia , commonly known in British English as Saudi Arabia and in Arabic as as-Sa‘ūdiyyah , is the largest state in Western Asia by land area, constituting the bulk of the Arabian Peninsula, and the second-largest in the Arab World...
; it has been imported to other countries in travelers from an area not known to be endemic for the disease.