NAME: Omsk hemorrhagic fever virus
SYNONYM OR CROSS REFERENCE: Omsk hemorrhagic fever, tick-borne encephalitis (far eastern subtype)
CHARACTERISTICS: Flaviviridae; spherical, enveloped virions about 45 nm in diameter, single-stranded, positive sense RNA genome
PATHOGENICITY: Sudden onset of fever, chills, headache, pain in lower and upper extremities and severe prostration; a papulovesicular rash on the soft palate, cervical lymphadenopathy and conjunctival suffusion are usually present; central nervous system abnormalities develop after one to two weeks; severe cases present with haemorrhages - no cutaneous rash; leukopenia and thrombocyopenia are marked; estimated case fatalities are 1-10%; previous infection leads to immunity
EPIDEMIOLOGY: Principally in the western Siberia regions of Omsk, Novosibirsk, Kurgan and Tjumen; occurring mostly in muskrat trappers; 2-41 cases reported between 1989-1998; all ages and both genders are susceptible; seasonal occurrence in each area coincides with vector activity
HOST RANGE: Humans, rodents, muskrat and possibly ticks
INFECTIOUS DOSE: Not known
MODE OF TRANSMISSION: By the bite of an infective tick (Dermacentor reticulatus and D. marginatus, Ixodes persulcatus); data suggests direct transmission from both muskrat to humans and virus contaminated water to humans
INCUBATION PERIOD: Usually 3-8 days
COMMUNICABILITY: Not directly transmitted from person-to-person; ticks remain infective for life
RESERVOIR: Rodents, muskrats and ticks
ZOONOSIS: Yes - disease can be acquired from direct contact with muskrats
VECTORS: Ticks (Dermacentor retiqulatus, D. marginatus, Ixodes persulcatus)
DRUG SUSCEPTIBILITY: No antivirals available to date
SUSCEPTIBILITY TO DISINFECTANTS: Sensitive to 70% ethanol, 1% sodium hypochlorite, 2% glutaraldehyde
PHYSICAL INACTIVATION: Sensitive to heating at 56° C for 30 minutes
SURVIVAL OUTSIDE HOST: Sensitive to drying
SURVEILLANCE: Monitor for symptoms; confirm by serological analysis and viral isolation
FIRST AID/TREATMENT: Administer supportive therapy
IMMUNIZATION: A formalized mouse-brain virus vaccine is in use - not available commercially
PROPHYLAXIS: None available
LABORATORY-ACQUIRED INFECTIONS: Six cases were reported up to 1987; two cases were due to aerosols generated from a broken vial in a centrifuge
SOURCES/SPECIMENS: Blood
PRIMARY HAZARDS: Accidental parenteral inoculation; droplet exposure of the mucous membranes
SPECIAL HAZARDS: Exposure to infectious aerosols
CONTAINMENT REQUIREMENTS: Biosafety level 4 practices and containment facilities for all activities involving the virus and potentially infectious fluids or tissues
PROTECTIVE CLOTHING: Street clothing is removed and replaced with complete laboratory clothing, the nature of which depends on the level 4 design
OTHER PRECAUTIONS: Clinical specimens from persons suspected of being infected with this virus should be submitted to a level 4 containment facility
SPILLS: Allow aerosols to settle; wearing protective clothing gently cover the spill with absorbent paper towel and apply 1% sodium hypochlorite starting at the perimeter and working towards the center; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate all wastes and materials from the containment laboratory before disposal; steam sterilization, chemical disinfection, incineration, gaseous methods; includes liquid and solid wastes
STORAGE: In sealed containers that are appropriately labelled and contained within the level 4 facility
Date prepared: March, 2001
Prepared by: Office of Laboratory Security, PHAC
Although the information, opinions and recommendations contained in this Material Safety Data Sheet are compiled from sources believed to be reliable, we accept no responsibility for the accuracy, sufficiency, or reliability or for any loss or injury resulting from the use of the information. Newly discovered hazards are frequent and this information may not be completely up to date.
Copyright ©
Health Canada, 2001
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