Hepatitis A is a communicable (or contagious) disease that spreads from person to person. It is transmitted by the “fecal — oral route.” This does not mean, or course, that Hepatitis A transmission requires that fecal material from an infectious individual must come in contact directly with the mouth of a susceptible individual. It is almost always true that the virus infects a susceptible individual when he or she ingests it, but it gets to the mouth by an indirect route.
Food contaminated with the virus is the most common vehicle transmitting Hepatitis A. The food preparer or cook is the individual most often contaminating the food. He or she is generally not ill: the peak time of infectivity (i.e., when the most virus is present in the stool of an infectious individual) is during the 2 weeks before illness begins. Hepatitis A is spread almost exclusively through fecal-oral contact, generally from person-to-person, or via contaminated food or water. Outbreaks associated with food have been increasingly implicated as a significant source of Hepatitis A infection. Such “outbreaks are usually associated with contamination of food during preparation by an HAV-infected food handler.”2 Indeed, “[v]iral gastroenteritis was reported as the most common food-borne illness in Minnesota from 1984 to 1991, predominantly associated with poor personal hygiene of infected food handlers.”3

Although ingestion of contaminated food is the most common means of spread for Hepatitis A, it may also commonly be spread by household contact among families or roommates, sexual contact, by the ingestion of contaminated water, by the ingestion of raw or undercooked fruits and vegetables or shellfish (like oysters), and by direct inoculation from persons sharing illicit drugs. Children often have asymptomatic or unrecognized infections and can pass the virus through ordinary play, unknown to their parents, who may later become infected from contact with their children.
Hepatitis A is much more common in countries with under-developed sanitation systems. This includes most of the world: an increased transmission rate is seen in all countries other than the United States, Canada, Japan, Australia, New Zealand, and the countries of Western Europe. Within the United States, Native American reservations also experience a greatly increased rate of disease.4
For a general overview of the hepatitis-A virus, see Epidemiology and Prevention of Vaccine-Preventable Diseases, The Pink Book, Chap. 13, 6th Ed (Jan. 2000).
Id. at 12; see also Carl M. Francis DP, Maynard JE, Foodborne hepatitis-A: Recommendations For Control, J. Infect. Dis. 1983; 148:1133-5.
Jaykus L, Epidemiology and Detection as Options for Control of Viral and Parasitic Foodborne Disease, EID, 1997, vol. 3, 4.
CDC. Prevention of Hepatitis A Through Active or Passive Immunization: Recommendations of the Advisory Committee of Immunization Practices (ACIP). MMWR 1999;48(RR-12).