Japanese Encephalitis Virus Agent Information Sheet

Boston University
Research Occupational Health Program (ROHP)
617-358-7647

Agent

Japanese encephalitis virus (JEV) is a single stranded, enveloped RNA virus which is about 40-50 nm in diameter, and belongs to the Flaviviridae family.   Also referred to as JE, JEV, Japanese B Encephalitis, Arbovirus B, and Mosquito-borne encephalitis virus.

Disease/Infection

Japanese encephalitis may present as a mild febrile illness or acute encephalitis with neuro-invasive symptoms that in a small percent have a high-case fatality rate, with neurologic sequelae in survivors.

Pathogenicity

Japanese encephalitis can cause self-limited to fatal disease.  Infants and elderly are more likely to develop severe cases.

Biosafety Information

Risk Group/BSL
Risk Group 3
Biosafety level:  BSL3/ABSL3

Modes of Transmission

JEV is transmitted as an enzootic cycle involving Culex mosquitoes that bite hosts.  Risks are highest in rural and agricultural areas.  In endemic areas, most over 15 years old have protected immunity from natural exposure to JEV.

Transmission
Skin Exposure (Needlestick, bite, or scratch):Yes
Mucous Membrane Splash to Eye(s), Nose or Mouth:Yes
Inhalation:JEV is a bloodborne agent and in nature a vector is needed for transfer, but theoretically possible.
Ingestion:Unlikely in laboratory setting

Host Range/Reservoir
Humans, birds, pigs, cattle, horses, bats, and reptile.  Pigs and birds are major amplifier.  Enzootic cycle maintained by Culex mosquitoes.

Symptoms                                                                                                                                                                                                                                                                              
1. Mild febrile illness:  may include fever, headache, or fatigue
2. Acute encephalitis:  headache and fever to chills, nauseau, vomiting, diarrhea, neck pain, photo-phobia, confusion, generalized weakness focal neurologic deficits, Parkinsonian syndrome, paralysis, seizures, or coma

    Incubation Period
    Usually 5-15 days

    Viability                                                                                                                                                                         

    a. Susceptible 70% ethanol, 2% glutaraldehyde, 3-8 % formaldehyde, 1% sodium hypochlorite, iodine, phenol iodophors and organic solvents/detergents.
    b. 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.
    c. No known drug resistances or susceptibilities

    Survival Outside Host

    Flaviviruses are unstable unless stored at -80o Vectors: Culex spp. and Aedes spp. mosquitos, survives for long periods in mosquito eggs.

    Information for Lab Workers

    Laboratory PPE

    Personal protective equipment includes but is not limited to laboratory coats or gowns, surgical masks, disposable gloves, safety glasses, face shield if risk of splash, and respirator (PAPR or N-95) if aerosol risk.

    Containment

    All work with infectious virus must be performed in BSL-3/ABSL-3 containment

    In Case of Exposure/Disease

    • For injuries in the lab which are major medical emergencies (heart attacks, seizures, etc…):
    • Medical Campus: call or have a coworker call the Control Center at 617-358–9090.
    • You will be referred to or transported to the appropriate health care location by the emergency response team.
    • For lab exposures (needle sticks, bite, cut, scratch, splash, etc…) involving animals or infectious agents, or for unexplained symptoms or illness call the ROHP 24/7 hour number (1-617-358-ROHP (7647); or, 8-ROHP (7647) if calling from an on-campus location) to be connected with the BU Research Occupational Health Program (ROHP) medical officer. ROHP will refer you to the appropriate health care location.
    • Under any of these scenarios, always inform the physician of your work in the laboratory and the agent(s) that you work with.
    • Provide the wallet-size BU medical surveillance card to the physician.

      Vaccination

      Japanese Encephalitis (JE) vaccine licensed for age>17 years, is 2 doses administered 28 days apart, and given at least 1 week prior to potential exposure. Timing and need for booster vaccination has not been determined.  A booster dose (third dose) should be given if a person has received the two-dose primary vaccination series one year or more previously and there is a continued risk for JE virus infection or potential for re-exposure.

      Information for First Responders/Medical Personnel

      Public Health Issues

      If you feel you have been exposed contact ROHP at 617-358-7647. Immediately following an exposure to JEV, the lab worker is not considered infectious. He/she can be cared for with standard PPE. In case of a lab worker presenting to Boston Medical Center Emergency Department or other outside medical facility, either the exposed worker or the caring physicians should immediately contact ROHP for further instructions. immediately

      Diagnosis/Surveillance

      Diagnosis can be through culturing a clinical sample, antigen detection or serological enzyme-linked immunosorbent assay (ELISA).

      First Aid/Post Exposure Prophylaxis

      Perform one of the following actions:

      Skin Exposure (Needlestick or scratch):Immediately go to the sink and thoroughly wash the wound with soap and water for 15 minutes. Decontaminate any exposed skin surfaces with an antiseptic scrub solution.
      Mucous Membrane Splash to Eye(s), Nose or Mouth:Exposure should be irrigated vigorously.
      Splash Affecting Garments:Remove garments that may have become soiled or contaminated and place them in a double red plastic bag.

      There is experimental evidence that administering immune plasma and alpha interferon might have some benefit after known exposure.

      Treatment

      Treatment is aggressive supportive care for severe illness and can be targeted towards symptom management for mild illness.  There are no antivirals known to be effective.

      References

      Hills SL, Walter EB, Atmar RL, Fischer M. Japanese Encephalitis Vaccine: Recommendations of the Advisory Committee on Immunization Practices. MMWR Recomm Rep 2019;68(No. RR-2):1–33. DOI: http://dx.doi.org/10.15585/mmwr.rr6802a1

      Mandell, G. L., J. E. Bennett, et al. (2010). Mandell, Douglas, and Bennett’s principles and practice of infectious diseases. Philadelphia, PA, Churchill Livingstone/Elsevier.

      Japanese Encephalitis. Shoreland Travax. (2021, February 4). Retrieved November 10, 2021, from https://private.travax.com/library/japanese-encephalitis.

      Chosewood, L. C., & Wilson, D. E. (2010). Biosafety in microbiological and biomedical laboratories. Books Express Pub.

      Public Health Agency of Canada. (2011, February 18). Pathogen Safety Data Sheets: Infectious Substances – Japanese encephalitis virus. Canada.ca. Retrieved November 3, 2021, from https://www.canada.ca/en/public-health/services/laboratory-biosafety-biosecurity/pathogen-safety-data-sheets-risk-assessment/japanese-encephalitis-virus-material-safety-data-sheets-msds.html

      https://www.cdc.gov/japaneseencephalitis/

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