Public Health Agency of Canada
Symbol of the Government of Canada

Share this page

Powassan encephalitis virus

 

PATHOGEN SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Powassan encephalitis virus

SYNONYM OR CROSS REFERENCE: Arbovirus

CHARACTERISTICS: Flaviviridae; 40-50 nm diameter, enveloped, ssRNA; virus exhibits high degree of neurotropism

SECTION II - HEALTH HAZARD

PATHOGENICITY: Resembles mosquito-borne encephalitis clinically; acute inflammatory disease of short duration involving parts of brain, spinal cord and meninges; asymptomatic and mild cases with febrile head ache or aseptic meningitis; severe infections with stupor, disorientation, coma, tremors, convulsions and spastic paralysis; high incidence of neurologic sequelae; 0.3 - 60% case fatality rate (highest case fatality rate among Arboviruses); infection whether inapparent or overt leads to immunity

EPIDEMIOLOGY: Present in Canada, USA and USSR; seasonal incidence depends on activity of tick vectors; highest incidence in rural or forested areas; greatest risk of disease transmission from June to September; males and children are more frequently infected; up to 27 reported cases in North America since 1958

HOST RANGE: Humans, woodchuck, snowshoe hare, coyotes, foxes, racoons and skunks, domesticated cats and dogs

INFECTIOUS DOSE: Unknown

MODE OF TRANSMISSION: By the bite of infective ticks, or possibly by consumption of raw milk from certain infected animals; larval ticks ingest virus by feeding on rodents, sometimes other mammals and birds, viral transfer from the blood to the CNS through the olfactory tract has been suggested

INCUBATION PERIOD: Usually 7-14 days

COMMUNICABILITY: Not directly transmitted from person-to-person; a tick infected at any stage remains infective for life; viremia in a variety of vertebrates may last for several days (in man up to 7-10 days)

SECTION III - DISSEMINATION

RESERVOIR: Tick or combination of tick and mammal

ZOONOSIS: Yes, through bite of an infected tick

VECTORS: Tick - Ixodes cookei, Ixodes marxi, Ixodes spinipalpus

SECTION IV - VIABILITY

DRUG SUSCEPTIBILITY: N/A

SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to 1% sodium hypochlorite, 2% glutaraldehyde, formaldehyde and 70% ethanol

PHYSICAL INACTIVATION: Inactivated by heat (50-60° C for at least 30 min)

SURVIVAL OUTSIDE HOST: Does not survive out of host

SECTION V - MEDICAL

SURVEILLANCE: Serological studies or isolation of virus from blood

FIRST AID/TREATMENT: No specific treatment

IMMUNIZATION: None available

PROPHYLAXIS: None available

SECTION VI - LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: 2 reported laboratory infections; laboratory infections with serious sequelae have been reported

SOURCES/SPECIMENS: Blood, CSF, urine and exudates

PRIMARY HAZARDS: Exposure to aerosols of infectious solutions and animal bedding; accidental parenteral inoculation; direct contact of broken skin

SPECIAL HAZARDS: None

SECTION VII - RECOMMENDED PRECAUTIONS

CONTAINMENT REQUIREMENTS: Biosafety level 3 practices, containment equipment, and facilities are recommended for activities using potentially infectious clinical materials and infected tissue cultures, animals, or arthropods

PROTECTIVE CLOTHING: Gloves and gown (tie in back and tight wrists) when working with agent

OTHER PRECAUTIONS: None

SECTION VIII - HANDLING INFORMATION

SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towels and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time before clean up

DISPOSAL: Decontaminate before disposal; steam sterilization, incineration

STORAGE: In sealed containers that are appropriately labelled (in locked level 3 facility)

SECTION IX - MISCELLANEOUS INFORMATION

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