female in lab protective gear working with Hepatitis A virus
(Image courtesy of CDC)

Hepatitis A

Compiled By: Julie A. Albrecht, Ph.D., Associate Professor

The Organism: The Hepatitis A virus is an ultramicroscopic organism that must have a living host to multiply. Food is used to transmit the viruses from person to person. The virus, when transferred to food, may survive for several days, even at refrigeration temperatures.

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Sources of the organism:

  • Intestinal tracts of infected humans
  • Contaminated water

Associated foods:

  • Seafood
  • Any food handled by an infected food handler

Organism Characteristics:

  • Virus; needs a live host to reproduce

The Disease: Persons with Hepatitis A foodborne illness may shed the virus in their feces long before disease symptoms appear. Persons infected with Hepatitis A virus should not handle food or work in a food establishment until they have received the proper medical treatment and are no longer shedding the virus. Hepatitis A vaccine is available.

Symptoms include:

  • Lethargy
  • Loss of appetite
  • Nausea
  • Vomiting
  • Fever
  • Jaundice

Onset time:

  • 10-50 days
  • Infective Dose:
  • Unknown but presumably 10-100 virus particles need to be consumed for symptoms of the illness to develop.

Duration of symptoms:

  • 2 weeks - 3 months


  • Thoroughly cook seafood including oysters.
  • Use proper hand washing techniques and practice good personal hygiene procedures.