NAME: Hepatitis B virus
SYNONYM OR CROSS REFERENCE: Serum hepatitis, type B hepatitis, homologous serum jaundice, Australia antigen hepatitis, HBV, viral hepatitis B, HB
CHARACTERISTICS: Partially double-stranded DNA, 42-47 nm diameter, enveloped, Hepadnaviridae; lipoprotein coat contains the HBsAg
PATHOGENICITY: Two major forms: asymptomatic infection and symptomatic hepatitis; onset is insidious with anorexia, vague abdominal discomfort, nausea and vomiting, sometimes arthralgias and rash, often progressing to jaundice; fever may be absent or mild; severity ranges from inapparent cases to fatal acute hepatic necrosis, or becomes chronically infected; low short term case fatality rate in hospitalized patients; long term case fatality rate is 2-3% due to cancer or cirrhosis of the liver; 95% of adult infections are self limited
EPIDEMIOLOGY: Worldwide; endemic with little seasonal variation; commonly in young adults in North America and in infancy or childhood in Africa and Asia; antigen carrier rate in North America is under 1% for the general population and 10-15% in Asia; common in high risk groups - drug abusers, persons in the health care field exposed to blood or serous fluids, sexually promiscuous individuals
HOST RANGE: Humans (chimpanzees are susceptible)
INFECTIOUS DOSE: Not known, however, 1 mL of infected blood may contain from 102-109 HBV particles
MODE OF TRANSMISSION: Percutaneous or permucosal exposure to infectious body fluids (blood, blood products, cerebral spinal fluid, serum-derived fluids, saliva, semen, vaginal fluids, unfixed tissues and organs), indirect contact with contaminated items in the laboratory; commonly spread by contaminated needles, syringes and other IV equipment; contamination of wounds or lacerations; exposure of mucous membranes; sexual contact, household contact, perinatal transmission from mother to infant, nosocomial exposure
INCUBATION PERIOD: Usually 24-180 days; average 60-90 days; HBsAg can appear in 2 weeks or rarely, 6-9 months, depending on dose, mode of transmission and host factors
COMMUNICABILITY: Blood can be infective weeks before onset of symptoms; remains infective through clinical and chronic carrier states; infectivity of chronically infected individuals varies from highly infectious to sparingly infectious; sera of infected individuals may contain as many as 1010 infectious virons per mL
RESERVOIR: Humans, chimpanzees are susceptible, but an animal reservoir in nature has not been recognized
ZOONOSIS: None
VECTORS: None
DRUG SUSCEPTIBILITY: No specific antivirals
SUSCEPTIBILITY TO DISINFECTANTS: Susceptible to many disinfectants; 1% sodium hypochlorite, 70% ethanol, 2% alkalinized glutaraldehyde, formaldehyde
PHYSICAL INACTIVATION: Stable at 37°C for 60 minutes and 56° C for 30 minutes but not at temperatures above 60°C; stable at pH 2.4 for up to 6 hours (some infectivity is lost); HBsAg not destroyed by UV of blood products; stable for years at -70° C
SURVIVAL OUTSIDE HOST: Survives in dried blood for long periods (weeks), stable on environmental surfaces for a least 7 days at 25° C
SURVEILLANCE: Testing of blood samples for the presence of HBsAg, EIA, RIA, PCR
FIRST AID/TREATMENT: Alpha interferon licensed for treatment of chronic infection. About 30% effective in elimination of "e" antigenemia; Lavivudine (reverse transcriptase inhibitor) is being investigated for chronic infections
IMMUNIZATION: Inactivated vaccine is available and recommended for those of increased risk such as laboratory workers and other health care workers exposed to blood
PROPHYLAXIS: Hepatitis B immunoglobulin (HBIG)
LABORATORY-ACQUIRED INFECTIONS: The most frequently occurring laboratory-associated infection; incidence in some categories of laboratory workers is 7 times greater that of the general population; 234 reported cases up to 1974 with one death (3921 total infections surveyed); 26 reported cases in UK laboratories from 1980-1987
SOURCES/SPECIMENS: Blood and blood products, urine, semen, CSF, and saliva
PRIMARY HAZARDS: Parenteral inoculation; droplet exposure of mucous membranes; contact exposure of broken skin
SPECIAL HAZARDS: Needle stick with infected blood
CONTAINMENT REQUIREMENTS: Biosafety level 2 practices and containment for activities utilizing infectious body fluids and tissues; biosafety level 3 primary containment and personnel precautions for activities with high potential for droplet or aerosol production and high production quantities or concentrations; animal biosafety level 2 for work with non-human primates
PROTECTIVE CLOTHING: Laboratory coat; gloves when skin contact is unavoidable and when working with animals; wrap-around gown and gloves for work in biosafety cabinet
OTHER PRECAUTIONS: General needle safety precautions important - do not bend, break or recap needles; dispose directly into puncture-proof container, universal precaution for blood, blood products or specimens containing or contaminated with blood
SPILLS: Allow aerosols to settle; wearing protective clothing, gently cover spill with absorbent paper towel and apply 1% sodium hypochlorite, starting at perimeter and working towards the centre; allow sufficient contact time (30 min) before clean up
DISPOSAL: Decontaminate before disposal; steam sterilization, chemical disinfection, incineration
STORAGE: In sealed containers that are appropriately labelled
Date prepared: May, 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