NAME: Hepatitis A virus (HAV).
SYNONYM OR CROSS REFERENCE: HAV, type A hepatitis, infectious hepatitis, epidemic hepatitis, epidemic jaundice, and catarrhal jaundiceFootnote 1 Footnote 2 Footnote 3 Footnote 4 Footnote 5 Footnote 6 Footnote 7 Footnote 8 Footnote 9 Footnote 10 Footnote 11.
CHARACTERISTICS: HAV is a member of the Picornaviridae family and Hepatovirus genusFootnote 1 Footnote 2 Footnote 3 Footnote 11. It is an icosahedral, non-enveloped, positive-sense RNA virus and is 27 to 32 nm in diameter. Seven HAV genotypes have been identified (I-VII), 4 of which are of human origin (I, II, III, and VII) Footnote 3.
PATHOGENICITY/TOXICITY: HAV only causes acute hepatitis and is not associated with chronic liver diseaseFootnote 1 Footnote 3. Most individuals infected with HAV develop non-specific constitutional signs and symptoms followed by gastrointestinal symptoms. Symptoms include fever, malaise, anorexia, nausea, abdominal discomfort, dark urine, and jaundiceFootnote 2 Footnote 3 Footnote 4 Footnote 11. The disease course typically lasts less than 2 monthsFootnote 3. In rare cases, HAV can cause severe cases of fulminant hepatitis with fatal outcomes in otherwise healthy adultsFootnote 2 Footnote 3.
EPIDEMIOLOGY: The World Health Organization estimates an annual total of 1.5 million case of hepatitis A worldwide, but seroprevalence data suggest that tens of millions of HAV infections occur each yearFootnote 4. Central and South America, Africa, India, the Middle East, and Asia have the highest seroprevalence rates, whereas North America, Japan, and Western Europe have among the lowestFootnote 2 Footnote 4. The incidence level is highly related to the prevailing level of hygiene and sanitation, with the disease being most prevalent in less developed parts of the worldFootnote 4.
HOST RANGE: HumansFootnote 1 Footnote 2 Footnote 3 Footnote 4 Footnote 7 Footnote 8 Footnote 10 Footnote 11 Footnote 12. Chimpanzees and other non-human primates such as marmosets, tamarins, owl monkeys, and Saimiri monkeys are also susceptible to HAVFootnote 1 Footnote 3 Footnote 9 Footnote 11 Footnote 12.
INFECTIOUS DOSE: Unknown.
MODE OF TRANSMISSION: HAV transmission usually occurs via the faecal-oral routeFootnote 1 Footnote 2 Footnote 4. The most common reported source of HAV infection is household or other close contact with an infected person. Other potential sources of infection include men having sex with men, travel to countries where HAV is endemic, and from contaminated drugs and needles following illicit drug useFootnote 3. Consumption of contaminated food and water are infrequent modes of transmission, and transmission by transfusion of blood or blood products is even rarerFootnote 3.
COMMUNICABILITY: Maximum infectivity occurs in the latter half of incubation and continues a few days after the onset of jaundiceFootnote 1 Footnote 4 Footnote 11. Chronic shedding of HAV in faeces does not occurFootnote 11.
DRUG SUSCEPTIBILITY: Triazolo[4,3-b]pyridazine derivatives show antiviral activity against HAV Footnote 5 but are not yet used clinically.
SUSCEPTIBILITY TO DISINFECTANTS: HAV is inactivated by 1 % sodium hypochlorite, formulations of quaternary ammonium compounds and HClFootnote 7, and 2 % glutaraldehydeFootnote 3 Footnote 4 Footnote 6.
SURVIVAL OUTSIDE HOST: HAV is exceptionally stable at ambient temperature and at low pH, thus allowing it to survive in the environment and to be transmitted via contaminated foods and drinking waterFootnote 1 Footnote 9.
SURVEILLANCE: A number of techniques have been employed to detect HAV, including RT- PCR, radioimmunoassay, ELISA, immunoblotting, and dot-blot gold filtrationFootnote 1 Footnote 2 Footnote 7 Footnote 8 Footnote 10 Footnote 12.
Note: All diagnostic methods are not necessarily available in all countries.
FIRST AID/TREATMENT: No specific treatment for HAV infection has been shown to be effectiveFootnote 2 Footnote 4. Bed rest and balanced nutrition are recommended, as is the avoidance of alcohol or other hepatotoxinsFootnote 2.
PROPHYLAXIS: Individuals who are known to have been exposed to HAV should be administered HAV immune globulin (0.02ml/kg body weight) within two weeks of the initial exposureFootnote 1 Footnote 2 Footnote 4. Inactivated HAV vaccines are highly effective in pre-exposure prophylaxis for laboratory workers and travellers to HAV endemic areasFootnote 1. There is also some evidence for effective post-exposure prophylaxis with HAV vaccine Footnote 4.
LABORATORY-ACQUIRED INFECTIONS: Unknown.
SOURCES/SPECIMENS: Faeces of infected humans and non-human primatesFootnote 1 Footnote 2 Footnote 3 Footnote 4
Footnote 9 Footnote 11. Other sources/specimens include blood, liver tissue, and bileFootnote 1 Footnote 7 Footnote 8.
SPECIAL HAZARDS: None.
RISK GROUP CLASSIFICATION: Risk Group 2 Footnote 13.
CONTAINMENT REQUIREMENTS: Containment Level 2 facilities, equipment, and operational practices for work involving infectious or potentially infectious materials, animals, 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 14.
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 limitedFootnote 14. Additional precautions should be considered with work involving animals or large scale activitiesFootnote 14.
SPILLS: Allow aerosols to settle and, wearing protective clothing, gently cover spill with paper towels and apply suitable disinfectants starting at the perimeter and working towards the centre. Allow sufficient contact time before clean up (30 min)Footnote 14.
DISPOSAL: Decontaminate all materials for disposal by steam sterilization, chemical disinfection, and/or incinerationFootnote 14.
STORAGE: In sealed containers that are appropriately labelledFootnote 14.
SECTION IX – REGULATORY AND OTHER INFORMATION
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: September 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, 2010