MATERIAL SAFETY DATA SHEET - INFECTIOUS SUBSTANCES

SECTION I - INFECTIOUS AGENT

NAME: Eastern equine encephalitis virus, Western equine encephalitis virus

SYNONYM OR CROSS REFERENCE: Eastern equine encephalomyelitis, Western equine encephalomyelitis, EEE, WEE, arbovirus

CHARACTERISTICS: 60 - 70 nm diameter, posititive ssRNA, enveloped; Togaviridae, Genus Alphavirus

SECTION II - HEALTH HAZARD

PATHOGENICITY: Acute inflammatory disease of short duration involving brain, spinal cord, and meninges; EEE mild cases often occur as febrile headache or aseptic meningitis; severe infections are marked by acute onset, headache, high fever, meningeal signs, stupor, disorientation, coma, tremors, occasional spastic convulsions and paralysis; up to 60% case fatality rate; WEE infections are asymptomatic or present as mild, nonspecific illness, mortality rate is about 3%

EPIDEMIOLOGY: EEE in eastern and north central USA and Canada, scattered areas of Central and South America and in Caribbean; WEE in western and central USA, Canada and parts of South America (Argentina); cases occur in temperate latitudes in summer and early fall, and are limited to areas and years of high temperature and many mosquitoes

HOST RANGE: Humans, horses, other animals, birds

INFECTIOUS DOSE: Unknown

MODE OF TRANSMISSION: By the bite of infective mosquitoes

INCUBATION PERIOD: Usually 5 to 15 days

COMMUNICABILITY: Not directly transmitted from person-to-person; virus is usually not demonstrated in blood or CSF of humans after onset of disease; viremia in birds lasts 2 to 5 days; mosquitoes are infective for life, possible vertical transmission (female to egg); viremia in horses rarely present in high titres for long periods

SECTION III - DISSEMINATION

RESERVOIR: Humans and horses are uncommon sources of mosquito infection; virus overwinters possibly in birds, other animals (rodents, bats, reptiles, amphibians), surviving mosquito eggs or adults (true reservoir unknown)

ZOONOSIS: Yes, from infected animals / birds via mosquitoes

VECTORS: EEE - Culiseta melanura ( USA and Canada) (bird to bird)
- Aedes, Coquillettidia spp. (bird or animal to humans)

WEE - Culex tarsalis (Western USA and Canada) (major epidemic vector)
- found in at least 5 genera of mosquitoes

SECTION IV - VIABILITY

DRUG SUSCEPTIBILITY: N/A

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

PHYSICAL INACTIVATION: Sensitive to moist and dry heat, drying

SURVIVAL OUTSIDE HOST: Does not survive outside of host

SECTION V - MEDICAL

SURVEILLANCE: Monitor for symptoms of arthropod-borne viral fever; serological identification and antibody titre, PCR, ELISA

FIRST AID/TREATMENT: No specific treatment

IMMUNIZATION: Investigational vaccines available and recommended for personnel who work directly and regularly with EEE and WEE in laboratory

PROPHYLAXIS: WEE immune globulin (human) available but efficacy of product has not been established

SECTION VI - LABORATORY HAZARDS

LABORATORY-ACQUIRED INFECTIONS: EEE - 4 reported cases; WEE - 7 reported cases with 2 deaths (associated with egg cultures, suckling mice and aerosols - broken lyophilized material)

SOURCES/SPECIMENS: Blood, CSF, central nervous system and other tissues, infected arthropods

PRIMARY HAZARDS: Accidental parenteral inoculation, contact with broken skin or mucous membranes, bites of infected laboratory arthropods, infectious aerosols

SPECIAL HAZARDS: Infection of newly hatched chickens is especially hazardous

SECTION VII - RECOMMENDED PRECAUTIONS

CONTAINMENT REQUIREMENTS: Biosafety level 3 practices, safety equipment, and facilities for activities with potentially infectious clinical materials and arthropods, for manipulations of infected tissue cultures, embryonated eggs and rodents and for infection of newly hatched chickens

PROTECTIVE CLOTHING: Laboratory coat; gloves and gown with tight wrists and tie in back should be worn while working with infectious materials

OTHER PRECAUTIONS: Vaccination of personnel working directly and regularly with EEE and WEE

SECTION VIII - HANDLING INFORMATION

SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with paper towel and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time before clean up (30 min)

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: January, 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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