Japanese Encephalitis Virus
Japanese Encephalitis Virus
MATERIAL SAFETY DATA SHEET – INFECTIOUS SUBSTANCES
SECTION I – INFECTIOUS AGENT
NAME: Japanese encephalitis virus
SYNONYM OR CROSS REFERENCE: JE, JEV, Japanese B encephalitis (JBE), Arbovirus B, Mosquito-borne encephalitis virus
CHARACTERISTICS: Single stranded, positive sense RNA, enveloped, 40-50 nm diameter, Family Flaviviridae (formerly Togaviridae); prototype member of Japanese encephalitis antigenic complex which also contains St. Louis encephalitis virus, Murray valley virus, and West Nile virus
SECTION II – HEALTH HAZARD
PATHOGENICITY: Acute inflammatory viral diseases of short duration involving parts of the brain, spinal cord and meninges; ranges from febrile headache syndrome to acute encephalitis; severe infections are marked by acute onset, headache, high fever, chills, nausea, and vomiting followed by nuchal rigidity, photophobia and objective neurologic signs, stupor, disorientation, coma, tremors, convulsions in children, and paralysis of the upper extremities; infants and elderly more likely to develop severe cases; fatality rate of 5-40%; 45-70% of severe cases develop neuropsychiatric sequelae, parkinsonism, convulsive disorder, paralysis, mental retardation
EPIDEMIOLOGY: JE in western Pacific islands from Japan to the Philippines and in many areas of Asia from Korea to Indonesia, China and India; cases occur in temperature latitudes in summer and early fall, and are limited to areas and years of high temperature and many mosquitoes
HOST RANGE: Humans, birds, pigs, cattle, horses, bats and reptiles
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: By the bite of infective mosquitoes
INCUBATION PERIOD: Usually 5-15 days
COMMUNICABILITY: Not directly transmitted from person-to-person; virus is not usually demonstrable in the blood of human after onset of disease, but can be isolated from the CNS fluid in 1/3 of acute cases; viremia in birds usually lasts 2-5 days; mosquitoes are infective for life; viremia in horses rarely present in high titer for long periods
SECTION III – DISSEMINATION
RESERVOIR: Pigs and birds are the major amplifying hosts; humans, horses and cattle are uncommon sources of mosquito infection; virus possibly overwinters in birds, other animals, mosquitos;
ZOONOSIS: Yes, from infected animals via mosquito bites; causes encephalitis in horses, spontaneous abortion and stillbirths in swine
VECTORS : Culex spp. and Aedes spp.
Most important vectors are:
-Culex tritaeniorhynchus (major epidemic vector)
-Culex vishnui complex -Culex gelidus (in the tropics)
-Culex fuscocephalus -Culex annulus
SECTION IV – VIABILITY
DRUG SUSCEPTIBILITY: Unknown
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to disinfectants – 70% ethanol, 2% glutaraldehyde, 3-8 % formaldehyde, 1% sodium hypochlorite, iodine, phenol iodophors and organic solvents/detergents
PHYSICAL INACTIVATION: Inactivated by heat; 50% reduction in 10 min at 50o C, complete inactivation in 30 min at 56o C; sensitive to UV and gamma irradiation
SURVIVAL OUTSIDE HOST: Survives for long periods in mosquito eggs (virus can be maintained overwinter in eggs)
SECTION V – MEDICAL
SURVEILLANCE: Monitor for symptoms, serological studies (detection of immunoglobulin M and G antibodies) or isolation of virus from blood, CSF or other body fluid
FIRST AID/TREATMENT: No specific treatment
IMMUNIZATION: Formalin inactivated vaccine (JE-VAX) is licensed in Canada and recommended for those of increased risk such as laboratory workers and travellers spending more than one month in endemic/epidemic areas during the transmission season; 3 doses of the vaccine scheduled on days 0, 7 and 30 are required for a good protection; vaccine is contraindicated for women who are pregnant and the immunocompromised; two live vaccines are licensed for use in China.
PROPHYLAXIS: Passively protect accidentally exposed laboratory workers by human or animal immune serum
SECTION VI – LABORATORY HAZARDS
LABORATORY-ACQUIRED INFECTIONS: 22 cases reported up to 1980 and no fatalities
SOURCES/SPECIMENS: Blood, cerebrospinal fluid (CFS), other tissues (brain), infected arthropods
PRIMARY HAZARDS: Direct contact with broken skin or mucous membranes, accidental parenteral inoculation, exposure of infectious aerosols
SPECIAL HAZARDS: Bites or scratches from experimental animals, including arthropods (mosquitoes)
SECTION VII – RECOMMENDED PRECAUTIONS
CONTAINMENT REQUIREMENTS: Biosafety level 3 practices, containment equipment, and facilities are recommended for all activities involving potentially infectious materials and infected tissue cultures, animals, or arthropods
PROTECTIVE CLOTHING: Laboratory coat, gloves and gown (tie in back and tight wrists) must be worn when working with infectious materials
OTHER PRECAUTIONS: Vaccination of personnel working directly and regularly with the JE; important precautions concerning needle safety – do not bend, break or recap needles and dispose directly into puncture-proof container
SECTION VIII – HANDLING INFORMATION
SPILLS: Allow aerosols to settle; wearing protective clothing, the spillage must be covered promptly with a paper towel and disinfectant poured gently on towel, working from the outside to inwards; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate before disposal: steam sterilization, incineration, chemical disinfection
STORAGE: In sealed containers that are appropriately labelled and locked in a 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
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