Viral hepatitis is a major global public health problem affecting hundreds of millions of people and is associated with significant morbidity and mortality. Five biologically unrelated hepatotropic viruses cause most of the global burden of viral hepatitis: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D (delta) virus (HDV), and hepatitis E virus (HEV).
Hepatitis A is a communicable (or contagious) disease that is acquired primarily by the fecal oral route either from person to person or through contaminated food or water. Food-related outbreaks are most commonly associated with contamination of food during preparation by an HAV-infected food handler. The food handler may not recognize they are contagious or ill because the peak time of infectivity—that is, when the most virus is present in the stool of an infected individual—occurs during the two weeks before symptoms begin. The clinical manifestations and duration of illness vary a great deal, with many persons, especially young children, showing no symptoms at all. The clinical signs of HAV infection include dark urine and, sometimes, clay-colored stool, often accompanied or followed by jaundice. Associated symptoms may involve fever, abdominal pain, loss of appetite, diarrhea, nausea, vomiting, headache, and extreme fatigue. Hepatitis A is the only common vaccine-preventable foodborne disease in the United States. Each year, approximately 3,700 to 10,000 cases of hepatitis A occur in the United States.