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Omsk hemorrhagic fever:
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Viral weapon
acting on
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Synopsis, Diagnosis, Symptoms,
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Safety Precautions for Omsk Hemorrhagic Fever Casualties |
Standard Precautions defined by the 1996 CDC guidelines should be adopted for handling patients.Tick control should be practiced.Biosafety level 4 practices should be adopted for handling of samples. |
| Causative organism: (Systematic name in 1997) |
Omsk hemorrhagic fever virus |
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| ICTV Acronym | OMSKV |
| Virus classification: | A member of the Tick-borne encephalitis virus complex of the Flaviviridae. Click here for a detailed description of Flaviviruses. |
| Vector involvement: | The disease is transmitted by the bite of hard-bodied (Ixodid) ticks of the genus Dermacentor. |
| Epidemiology of natural outbreaks: | The hosts for the virus are rodents especially muskrats and voles and the commonest reason for infection is handling of infected animals. Distribution is limited to a large area surrounding Omsk in Siberia. |
Common findings include: fever, chills, headache, pain in lower and upper extremities and severe prostration; a rash on the soft palate, swollen glands in the neck.
Symptoms and effects.
The virus has an incubation period of 3-8 days before the sudden onset of symptoms: fever, chills, headache, pain in lower and upper extremities and severe prostration; a rash on the soft palate, swollen glands in the neck and the appearance of blood in the eyes (conjunctival suffusion). Other forms of hemorrhage including epistaxis (nosebleeds) and gastrointestinal and uterine bleeding may be seen. The lungs may also be affected. The disease is biphasic, i.e. after the initial appearance of symptoms there may a brief period of recovery before new symptoms arise. In the the case of Omsk hemorrhagic fever, the second phase develops after 1-2 weeks and affects the central nervous system. Fatalities are relatively low at 1-10%.
Medical and Physical Countermeasures.
Vaccination (Immunoprophylaxis)
A vaccine is not available.
Specific Therapy
No specific therapies are available.
Supportive care Minimize intrusive care to protect a weakened vascular bed. Attempt replacement therapy only in the case of severe hemorrhage. Fluid infusion to deal with dehydration is often counterproductive, but can be supportive if careful monitoring if accompanied by careful monitoring of serum electrolytes.
Decontamination
The virus is killed by 70% ethanol, 1% sodium hypochlorite, 2% glutaraldehyde, by heating to 56°C for 30 minutes and by drying. The virus can survive in water.
Agent Properties and Potential Uses
The virus is native to western areas of Siberia and is carried by ticks of the genera Dermacentor and Ixodes. The animal hosts are rodents and the muskrat Ondatra zibethica. The virus is transmitted by the bite of an infected tick or it can be caught from infected muskrats. It is not transmitted between humans. Aerosol infections have occurred in the laboratory. The virus is susceptible to drying but survives in water and may be transmissible to humans through contaminated water.
Terrorist Acquisition and Attempted Use.
| Disease | ICD-9-CM | ICD-10 |
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| Omsk hemorrhagic fever | 065.1 | A98.1 |
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