Omsk hemorrhagic fever
Omsk hemorrhagic fever is endemic to Western Siberia and Russia. This tick-borne viral infection causes a flu-like illness with cough, conjunctivitis, stomatitis, and flushing of the face and trunk. Some patients have pneumonitis and CNS disease.
CASES/YEAR
0 (US); 150 (Global)
INCUBATION
3-7 days (range of 1-12 days); [CCDM]
INITIAL SYMPTOMS
Flu-like illness with cough, conjunctivitis, stomatitis, and flushing of the face and trunk; Pneumonitis and CNS disease in some patients;
PRECAUTIONS
No person-to-person transmission; [ABX Guide]
COMMENTS
This tickborne viral infection is similar to Kyasanur forest disease and may cause marked leukopenia and thrombocytopenia. Hemorrhages and shock are seen in severe cases. Patients may have low back and limb pain, conjunctivitis, cervical lymphadenopathy, sore throat, and papulovesicular eruptions may occur. Some patients have a biphasic course developing meningoencephalitis 1-2 weeks after the initial febrile period. The case-fatality rate varies from 1-3%. A vaccine is available. Ticks are reservoirs. Animal hosts include native water voles and muskrats. Muskrats can directly transmit the infection to humans. [CCDM, p. 43-5] Tick-borne hemorrhagic fevers (Crimean-Congo, Kyasanur Forest, and Omsk) are typically biphasic illnesses that begin with flu-like symptoms and end with hepatomegaly and bleeding diathesis (petechiae, thrombocytopenia, and DIC). [PPID, p. 3520t, 3521] The heart is occasionally affected. [Cecil, p. 2217t]
DIAGNOSTIC
PCR; Viral culture; Paired sera; [CCDM]
SCOPE
Western Siberia, Russia; [CCDM]
SIGNS & SYMPTOMS
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>fatigue, weakness
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>fever
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>fever, biphasic or relapsing
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>myalgia
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E epistaxis
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E stomatitis
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G blood in stool
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G diarrhea
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G hematemesis
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G hepatomegaly
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G liver function test, abnormal
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G nausea, vomiting
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H leukopenia
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H lymphadenopathy
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H splenomegaly
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H thrombocytopenia
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N headache
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N lethargy
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O conjunctivitis, acute
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R cough
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R hemoptysis
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S petechiae and ecchymoses
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*acute renal failure
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*bleeding tendency
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*encephalitis
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*meningitis
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*myocarditis
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*pneumonitis
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*shock
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*uveitis
ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
RESERVOIR
Rodents, Wild Animals
RISK FACTORS
- Handle infected rodents (not bite)
- Travel to endemic area
- Victim--air release of infectious agents
- Work in a medical or research lab
- Work or play in tick-infested area
TREATMENT
No specific treatment; [CDC website 19June2013]
REFERENCES FOR CASES/YEAR
1.
2. (Global) 1500 cases resulted from outbreaks between 1945 and 1958 in western Siberia following the introduction of muskrats into the region; Infections occurred in trappers and laboratory workers. [PPID, p. 2038] 100-200 cases/year; [Cecil, p. 2215t]