Omsk hemorrhagic fever (OHF) is endemic to western Siberia, where the Omsk hemorrhagic fever virus (OHFV) is primarily spread through contact with infected muskrats, ticks and contaminated water. There is no male or female predominance, and no human to human transmission.

OHF is mainly characterized by the presence of a fever, as well as bleeding diathesis. From the time of infection, symptoms may take between 3 days and 1 week to appear, occasionally preceded by malaise.

Initially, patients experience high-grade fever for up to 2 weeks, often accompanied by chills. They may also experience a headache, cough, myalgia and gastrointestinal disturbance. Bleeding can occur from multiple sites, commonly the nose and mouth. Other organs such as the uterus, gastrointestinal tract, urinary tract, lungs and skin may also bleed, resulting in complaints that include hemoptysis, hematuria, petechiae and easy bruising, with an accompanying maculopapular rash on the torso and extremities in rare cases [1] [2].

There is widespread hyperemia often seen on the upper body, dry mucous membranes, halitosis, dehydration, as well as oropharyngeal and facial edema [1]. Many individuals become hypotensive and bradycardic. Hepatomegaly may also be diagnosed. Leukopenia and thrombocytopenia are usually present. The clinical condition worsens during the course of a few days, with additional symptoms such as gingivitis, gingival bleeding, myalgia, lymphadenopathy and hyperesthesia.

OHF is divided into two phases. The second phase of infection is only experienced by some individuals, commencing 3 weeks after the onset of symptoms. It involves the central nervous system, causing encephalitis, meningism, brain edema, and disruption of the blood-brain barrier.

There is dilation of blood vessels, increased blood flow, stasis and edema, causing tissue atrophy in the heart and liver, among other organs. Renal injury and pneumonia have been reported [1].

Despite the plethora of symptoms, the case fatality rate is low; literature states that it is between 0.4-10%, and full recovery is the norm. Patients may have lingering general body weakness. In a minority of cases, there is permanent hearing impairment, hair loss, and neurological sequelae such as memory impairment, psychiatric disorders, and behavioral changes. The most common causes of death are internal bleeding or severe sepsis, as OHF causes increased susceptibility to secondary infections [1].

The classic presentation, as described above, is seen in only one in five patients [3]. There are reported cases where the only sign of the disease is abnormal bleeding [3] [4].

• Fever

  Omsk hemorrhagic fever (OHF) is caused by Omsk hemorrhagic fever virus (OHFV), a member of the virus family Flaviviridae. OHF was described between 1945 and 1947 in Omsk, Russia from patients with hemorrhagic fever. [cdc.gov]

  […] omphalosite Omsk hemorrhagic fever on See More Nearby Entries Cite this Entry “Omsk hemorrhagic fever.” [merriam-webster.com]

  Species: Omsk hemorrhagic fever virus Synonyms[3] Omsk haemorrhagic fever virus Omsk hemorrhagic fever is caused by Omsk hemorrhagic fever virus (OHFV), a member of the Flavivirus family. [en.wikipedia.org]

• Cough

  Symptoms of Omsk hemorrhagic fever virus includes fever, headache, severe muscle pain, cough, dehydration, gastrointestinal symptoms and bleeding problems. After 1-2 weeks of symptoms, some patients recover without complication. [histopathology-india.net]

  They may also experience a headache, cough, myalgia and gastrointestinal disturbance. Bleeding can occur from multiple sites, commonly the nose and mouth. [symptoma.com]

  The symptoms of this disease include fever, headache, nausea, severe muscle pain, cough, and moderately severe haemorrhagic manifestations. A third of patients develop pneumonia, nephrosis, meningitis, or a combination of these complications. [ncbi.nlm.nih.gov]

  Clinical symptoms and signs of VHFs may include early onset of symptoms lasting for less than 1 week including fever, nausea and vomiting, joint and muscle pain, headache, extreme weakness, lack of strength, fatigue, sore throat, cough, chest and abdominal [hancockcountyhealthdepartment.com]

  After an incubation period of 3-8 days, the symptoms of OHF begin suddenly with fever, headache, severe muscle pain, cough, dehydration, gastrointestinal symptoms and bleeding problems. [web.archive.org]

• Diarrhea

  […] of VHFs may include early onset of symptoms lasting for less than 1 week including fever, nausea and vomiting, joint and muscle pain, headache, extreme weakness, lack of strength, fatigue, sore throat, cough, chest and abdominal pain, and nonbloody diarrhea [hancockcountyhealthdepartment.com]

• Myalgia

  They may also experience a headache, cough, myalgia and gastrointestinal disturbance. Bleeding can occur from multiple sites, commonly the nose and mouth. [symptoma.com]

  Homepage Rare diseases Search Search for a rare disease Omsk hemorrhagic fever Disease definition Omsk hemorrhagic fever (OHF), caused by Omsk hemorrhagic fever virus (OHFV), is a zoonotic disease characterized by fever, nausea, myalgia and moderately [orpha.net]

  Common symptoms include fever, headache, myalgia, and cough as well as bradycardia, dehydration, hypotension, and gastrointestinal symptoms Footnote 1 - Footnote 3, Footnote 5. [phac-aspc.gc.ca]

  Clinical manifestations of viral hemorrhagic fevers (VHFs) may include fever, myalgias, rash, and encephalitis, but presentations vary depending on the virus, the authors say. [cidrap.umn.edu]

  Common symptoms include fever, headache, myalgia, and cough as well as bradycardia, dehydration, hypotension, and gastrointestinal symptoms Footnote 1-Footnote 3Footnote 5. [canada.ca]

• Renal Injury

  Renal injury and pneumonia have been reported. Despite the plethora of symptoms, the case fatality rate is low; literature states that it is between 0.4-10%, and full recovery is the norm. Patients may have lingering general body weakness. [symptoma.com]

• Headache

  The first signs and symptoms of OHF may begin between 3 to 8 days after exposure and may include chills, fever, nausea, headache, and severe muscle pain. [malacards.org]

  Symptoms of OHF begin suddenly after about 3-8 days of infection, with chills, fever, headache, severe muscle pain, vomiting, and bleeding problems. [globalgenes.org]

  It is characterized by fever, headache, epistaxis, GI and uterine bleeding, and other hemorrhagic manifestations. Treatment is supportive; recovery usually occurs. Omsk hemorrhagic fever [medical-dictionary.thefreedictionary.com]

Diagnosis of Omsk hemorrhagic fever is clinical, coupled with the knowledge of the endemic locations of the infection. Laboratory tests include serology such as enzyme-linked immunosorbent assay (ELISA), neutralization tests (NTs), complement fixation (CF) tests and hemagglutination inhibition (HI) [5]. NT has the highest specificity, while CF has low sensitivity and should be used in conjunction with other tests. It is often not possible to directly detect the virus through the polymerase chain reaction as the body clears the virus before the onset of symptoms. OHFV is part of the Flaviviridae family, thus other flaviviruses are able to cross-react and thus produce false positive results for OHF. In particular, OHFV is extremely similar to Tick-borne encephalitis virus (TBEV), both in presentation and biochemical findings. It may be difficult to detect OHFV antibodies in the elderly, as they have a less pronounced response to the virus.

Treatment Since there is no specific treatment, avoid activities with risks of tick exposure. Apply insect repellent on skin and use protective clothing when doing activities outdoors. [medigest.uk]

It has been used in the treatment of CCHF patients reportedly with some benefit. How is Omsk hemorrhagic fever treated? There is no specific treatment for OHF, but supportive therapy is important. [web.archive.org]

[…] with Micronized Purified and their treatment with micronized purified flavonoid varices decreased. [ocytaqutepokiku.xpg.uol.com.br]

The material is in no way intended to replace professional medical care by a qualified specialist and should not be used as a basis for diagnosis or treatment. [orpha.net]

It was developed as a potential treatment for flavivirus infections, and shows broad spectrum antiviral activity against many related viruses such as Dengue virus, West Nile virus, yellow fever virus, Powassan virus, Hepatitis C virus, Kyasanur Forest [eng.ichacha.net]

Certain conditions have both an underlying etiology and multiple body system manifestations due to the underlying etiology. [icd10coded.com]

Comprehensive work for decryption of the etiology of the OHF by specialists from the Omsk and Moscow Institutes is carried out. [pesquisa.bvsalud.org]

Etiology 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. [infogalactic.com]

Descriptive epidemiology 2. Summary of clinical features 3. Global status of the disease 4. Status of the disease in a specific country 5. [books.google.com]

Article in Russian | MEDLINE | ID: mdl-25929029 The main aspects of epidemiology and epizootology of the Omsk hemorrhagic fever (OHF) are analyzed. [pesquisa.bvsalud.org]

The arboviruses: epidemiology and ecology Volume III: 205-216, 1988 Omsk hemorrhagic fever (state of the art). Voprosy Virusologii (3): 4-9, 2000 Hemorrhagic syndrome in patients with Omsk fever. [eurekamag.com]

We review the biological properties of the virus, and the epidemiological and clinical characteristics of Omsk haemorrhagic fever. Copyright © 2010 Elsevier Ltd. All rights reserved. [ncbi.nlm.nih.gov]

Weekly epidemiological record [Internet] 2011[cited 2016 Nov 30];86(24): [241-56]. Available from: Available from: http://www.who.int/wer/2011/wer8624.pdf [ Links ] 3. Organización Mundial de la Salud [Internet]. [scielo.org.co]

Prevention[edit] Preventing Omsk Hemorrhagic Fever consists primarily in avoiding being exposed to tick. [en.wikipedia.org]

Prevention Preventing Omsk Hemorrhagic Fever consists primarily in avoiding being exposed to tick. [medbox.iiab.me]

1. Růžek D, Yakimenko VV, Karan LS, Tkachev SE. Omsk haemorrhagic fever. Lancet. 2010;376(9758):2104-2113.
2. Lebedev, EP, Sizemova, GA, Busygin, FF. Clinical and epidemiological characteristics of Omsk hemorrhagic fever. Zh. Mikrobiol. 1975;11:132-133.
3. Busygin GG. Omks hemorrhagic fever—Current status of the problem.Vopr Virusol. 2000;45(3):4-9.
4. Belov GF, Tofaniuk EV, Kurzhukov GP, Kuznetsova VG. Clinico-epidemiological characterization of Omsk hemorrhagic fever at the period of 1988–1992. Zh Mikrobiol Epidemiol Immunobiol. 1995;(4): 88-91.
5. Centers for Disease Control and Prevention. Omsk Hemorrhagic Fever (OHF). Centers for Disease Control and Prevention. https://www.cdc.gov/vhf/omsk/diagnosis/index.html. Updated December 9, 2013. Accessed August 12, 2017.