View source for Omsk hemorrhagic fever

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'''Omsk hemorrhagic fever''' is a [[viral hemorrhagic fever]] caused by a [[Flavivirus]].<ref name="pmid15593010">{{cite journal |vauthors=Holbrook MR, Aronson JF, Campbell GA, Jones S, Feldmann H, Barrett AD |title=An animal model for the tickborne flavivirus--Omsk hemorrhagic fever virus |journal=J. Infect. Dis. |volume=191 |issue=1 |pages=100–8 |date=January 2005 |pmid=15593010 |doi=10.1086/426397 |url=http://www.journals.uchicago.edu/cgi-bin/resolve?JID33019}}</ref>

It is found in [[Siberia]].<ref name="pmid12951023">{{cite journal  |vauthors=Lin D, Li L, Dick D, etal |title=Analysis of the complete genome of the tick-borne flavivirus Omsk hemorrhagic fever virus |journal=Virology |volume=313 |issue=1 |pages=81–90 |date=August 2003 |pmid=12951023 |doi= 10.1016/S0042-6822(03)00246-0}}</ref> It is named for an outbreak in [[Omsk]].

==Signs and symptoms==
There are a number of symptoms of the virus. In the first 1–8 days the first phase begins. The symptoms in this phase are:
*[[Chills|chill]]s
*[[headache]]
*pain in the lower and upper extremities and severe [[prostration]]
*a rash on the soft [[palate]]
*swollen [[gland]]s in the neck
*appearance of blood in the eyes ([[conjunctival suffusion]])
*[[dehydration]]
*[[hypotension]]
*gastrointestinal symptoms (symptoms relating to the stomach and intestines)
*patients may also experience effects on the [[central nervous system]]

In 1–2 weeks, some people may recover, although others might not. They might experience a focal [[hemorrhage]] in mucosa of gingival, [[uterus]], and [[lung]]s, a [[papulovesicular]] rash on the soft palate, [[cervical lymphadenopathy]] (it occurs in the neck which that enlarges the lymph glandular tissue), and occasional [[neurology|neurological]] involvement. If the patient still has OHF after 3 weeks, then a second wave of symptoms will occur. It also includes signs of encephalitis. In most cases if the sickness does not fade away after this period, the patient will die. Patients that recover from OHF may experience hearing loss, hair loss, and behavioral or psychological difficulties associated with neurological conditions.

==Cause==

{{Taxobox
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| name = ''Omsk hemorrhagic fever virus''
| virus_group = iv
| familia = [[Flaviviridae]]
| genus = ''[[Flavivirus]]''
| species = '''''Omsk hemorrhagic fever virus'''''
}}
Omsk hemorrhagic fever is caused by the Omsk hemorrhagic fever virus (OHFV), a member of the [[Flavivirus]] family. The virus was discovered by [[Mikhail Chumakov]] and his colleagues between 1945 and 1947 in [[Omsk]], [[Russia]]. The infection is found in [[Western Siberia]], in places including [[Omsk Oblast]], [[Novosibirsk Oblast]], [[Kurgan Oblast]], [[Tyumen Oblast]]. The virus survives in water and is transferred to humans via contaminated water or an infected tick.

===Spread===
The main hosts of OHFV are rodents like the non-native [[muskrat]]. OHFV originates in ticks, who then transmit it to rodents by biting them. Humans become infected through tick bites or contact with a muskrat. Humans can also become infected through contact with [[blood]], [[feces]] or [[urine]] of a dead or sick muskrat (or any type of rat). The virus can also spread through milk from infected goats or sheep.  There is no evidence that the virus is contagious among humans.

===Evolution===

The virus appears to have evolved within the last 1000 years.<ref name=Karan2013>Karan LS, Ciccozzi M, Yakimenko VV, Presti AL, Cella E, Zehender G, Rezza G, Platonov AE (2013) The deduced evolution history of Omsk hemorrhagic fever virus. J Med Virol doi: 10.1002/jmv.23856</ref> The viral genomes can be divided into 2 clades—A and B. Clade A has five genotypes and clade B has one. These clades separated about 700 years ago. This separation appears to have occurred in the Kurgan province. Clade A subsequently underwent division into clade C, D and E 230 years ago. Clade C and E appear to have originated in the Novosibirsk and Omsk Provinces respectively. The muskrat ''[[Ondatra zibethicus]]'' which is highly susceptible to this virus was introduced into this area in the 1930s.

==Diagnosis==
Omsk Hemorrhagic Fever could be diagnosed by isolating virus from blood, or by [[serology|serologic testing]] using immunosorbent serological assay. OHF rating of fatality is 0.5–3%. There is no specific treatment for OHF so far but one way to help get rid of OHF is by supportive [[therapy]]. Supportive therapy helps maintain hydration and helps to provide precautions for patients with bleeding disorders.

==Prevention==
Preventing Omsk Hemorrhagic Fever consists primarily in avoiding being exposed to [[tick]]. Persons engaged in camping, farming, forestry, hunting (especially the Siberian [[muskrat]]) are at greater risk and should wear protective clothing or use insect repellent for protection. The same is generally recommended for persons at sheltered locations.

==References==
{{Reflist}}

== External links ==
{{Medical resources
|  DiseasesDB      = 31095  
|  ICD10           = {{ICD10|A|98|1|a|90}}  
|  ICD9            = {{ICD9|065.1}}  
|  ICDO            =  
|  OMIM            =  
|  MedlinePlus     =  
|  eMedicineSubj   =  
|  eMedicineTopic  =  
|  MeshID          = D006481 
}}
* https://www.cdc.gov/ncidod/dvrd/spb/mnpages/dispages/omsk.htm

{{Zoonotic viral diseases}}
{{Tick-borne diseases}}

{{DEFAULTSORT:Omsk Hemorrhagic Fever}}
[[Category:Hemorrhagic fevers]]
[[Category:Arthropod-borne viral fevers and viral haemorrhagic fevers]]