NAME: Hepatitis D Virus
SYNONYM OR CROSS REFERENCE: HDV, Delta Hepatitis(Footnote 1)
CHARACTERISTICS: Hepatitis D virus is currently unclassified and has been assigned to its own separate genus: Deltavirus(Footnote 1). The HDV virion is 36 to 43 nm in diameter. It contains a circular or linear RNA genome surrounded by a nucleocapsid protein called HDV antigen which is in turn surrounded by an envelope consisting of Hepatitis B surface antigen (HBsAg)(Footnote 2). HDV requires hepatitis B virus (HBV) as a helper virus and as such can only infect individuals who have also been infected with HBV(Footnote 1,Footnote 3).
PATHOGENICITY/TOXICITY: There are two major types of infection, HDV and HBV coinfection and HDV superinfection in individuals with chronic hepatitis B. Coinfection results in clinical hepatitis which is indistinguishable from acute hepatitis B(Footnote 4). Initial symptoms may include fatigue, lethargy, abdominal discomfort, anorexia, and nausea(Footnote 1,Footnote 2). This leads to jaundice and the persistence of fatigue and nausea. The disease is self-limiting and complete viral clearance occurs in more than 90% of cases(Footnote 2,Footnote 5). HDV superinfection generally causes severe acute hepatitis and leads to chronic hepatitis D infection in 90% of cases(Footnote 1). Individuals with chronic hepatitis D can develop cirrhosis (60-70%) or fulminant hepatitis. Fulminant hepatitis is characterized by severe hepatitis and encephalopathy and has a mortality rate of almost 80%. The overall mortality rate for HDV is between 2-20%(Footnote 2).
EPIDEMIOLOGY: HDV infections occur worldwide, and 15-20 million people are thought to be coinfected or superinfected with HDV(Footnote 5). The virus is highly endemic in Mediterranean countries, the Middle East, Central Africa and northern parts of South America(Footnote 5). In North America, injection drug users have the highest risk of contracting HDV(Footnote 2,Footnote 3).
HOST RANGE: Humans and, experimentally, chimpanzees and woodchucks(Footnote 1).
INFECTIOUS DOSE: Unknown
MODE OF TRANSMISSION: Transmitted through blood or blood products, parenteral inoculation (i.e. by injection drug use), or sexual contact. Individuals must also be infected with HBV(Footnote 3).
INCUBATION PERIOD: HDV superinfection: 2-8 weeks; HBV and HDV co-infection: 45- 160 days(Footnote 3).
COMMUNICABILITY: Low communicability; can pass from person-to-person through direct contact (e.g . blood-transfusions, contaminated needles, and sexual contact)(Footnote 3).
RESERVOIR: Humans(Footnote 1).
DRUG SUSCEPTIBILITY: Susceptible to alfa interferon (IFN-α)(Footnote 1).
SUSCEPTIBILITY TO DISINFECTANTS: Unknown; however, other hepatitis viruses are susceptible to 1-2% glutaraldehyde, 6-10% hydrogen peroxide, 8-12% formaldehyde, iodophores (40-50 mg/L free iodine), chlorine compounds (500-5000 mg/L free chlorine), and 0.5-3% phenolic compounds(Footnote 6).
PHYSICAL INACTIVATION: Unknown; however, other hepatitis viruses can be inactivated by moist heat (121*C for 15 min) and dry heat (170*C for 1h or 160*C for 2h)(Footnote 6).
SURVIVAL OUTSIDE HOST: Can survive in blood and blood products under the conditions used for the storage of such products(Footnote 1).
SURVEILLANCE: Monitor for symptoms. Diagnosis is based on serological testing for the presence of IgM or IgG antibodies to the delta antigen(Footnote 2,Footnote 4). PCR can also be used to detect viral DNA in clinical samples(Footnote 1).
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: Long-term treatment with high doses of IFN-α shows some improvement in clinical outcome(Footnote 1,Footnote 4). Hepatitis D is highly difficult to treat because of the severity of resulting illness and the distinctiveness of this virus(Footnote 1).
IMMUNIZATION: There is a vaccine for HBV which will prevent infection with HBV and HDV in HBV seronegative individuals(Footnote 3).
PROPHYLAXIS: Personnel exposed to HDV can be given the vaccine for hepatitis B virus and/or hepatitis B immunoglobulin to prevent coinfection of HBV and HDV(Footnote 6).
LABORATORY ACQUIRED INFECTIONS: No cases of laboratory-acquired HDV infection have been reported.
SOURCES / SPECIMENS: Blood and blood products(Footnote 2).
SPECIAL HAZARD: Individuals infected with HBV are at risk for infection with HDV(Footnote 7).
RISK GROUP CLASSIFICATION: Risk Group 2(Footnote 8).
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, or cultures.
PROTECTIVE CLOTHING: Lab coat. Gloves when direct skin contact with infected materials or animals is unavoidable. Eye protection must be used where there is a known or potential risk of exposure to splashes(Footnote 9).
OTHER PRECAUTIONS: All procedures that may produce aerosols, or involve high concentrations or large volumes should be conducted in a biological safety cabinet (BSC). The use of needles, syringes, and other sharp objects should be strictly limited. Additional precautions should be considered with work involving animals or large scale activities(Footnote 9).
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover the spill with paper towels and apply appropriate disinfectant starting at the perimeter and working towards the center. Allow sufficient contact time before clean up(Footnote 9).
DISPOSAL: Decontamination using steam sterilization, chemical disinfection, or incineration must be performed before disposal of infectious waste(Footnote 9).
STORAGE: All infectious materials should be stored in sealed containers bearing the appropriate labeling(Footnote 9).
REGULATORY INFORMATION: The import, transport, and use of pathogens in Canada is regulated under many regulatory bodies, including the Public Health Agency of Canada, Health Canada, Canadian Food Inspection Agency, Environment Canada, and Transport Canada. Users are responsible for ensuring they are compliant with all relevant acts, regulations, guidelines, and standards.
UPDATED: November 2010
PREPARED BY: Pathogen Regulation Directorate, Public Health Agency of Canada
Although the information, opinions and recommendations contained in this Pathogen 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.
Public Health Agency of Canada