Hepatitis A
Hepatitis A is a disease of the liver caused by the hepatitis A virus. Hepatitis A is spread primarily through food or water contaminated by feces from an infected person (i.e., an object contaminated with the stool of a person with hepatitis A is put into another person's mouth) and rarely through contact with infected blood.
If symptoms are present, they include yellow skin or eyes, fever, weakness, tiredness, stomach ache, nausea, abdominal pain, loss of appetite, and dark urine. Adolescents and adults are more likely to develop signs and symptoms of the disease than young children, so a child may be infected without a parent knowing.
Each year in the United States, hepatitis A infection causes 125,000 to 200,000 people to become sick, and 70 to 100 deaths. Hepatitis A disease tends to occur in community-wide outbreaks sometimes attributed to many people having eaten from the same hepatitis A-infected food source or transmission from person to person in households and extended family settings.
An infected person is most likely to spread hepatitis A virus during the two-week period before they know they are infected. Since most infected pre-school children show no symptoms of hepatitis A infection, they often unknowingly spread the virus to others including their pre-school classmates. Historically, children 2 to 18 years of age have had the highest rates of hepatitis A infections (15 to 20 cases per 100,000 in the early to mid 1990s).
Since the introduction of the hepatitis A vaccine in 1995 the rates have been on the decline, and since 2002 the rate has become similar in all age groups with an estimated 20,000 cases in the United States in 2004. The last Centers for Disease Control and Prevention (CDC) Summary of Notifiable Diseases that reported hepatitis A information indicated that 2005 showed the lowest number of newly reported cases ever in the United States.
