Hepatitis A (formerly known as infectious hepatitis), acute infectious disease of the liver caused by hepatitis A virus (HAV), virus RNA, usually spread causing fecal-oral route, transmitted from person to person through ingestion of contaminated food or water or by direct contact infectious person. Millions of people worldwide are estimated to be infected with HBV each year. The time between infection and the onset of symptoms (incubation period) ranges from two to six weeks and the average incubation period is 28 days.
In developing countries and in regions with poor hygienic standards, the incidence of infections with this virus is high, and the disease usually appear in early childhood. If income and access to clean water increased, the incidence of HAV. Hepatitis A infection causes no clinical signs and symptoms in more than 90% of infected children, the infection gives lifelong immunity, the disease is not particularly important for those infected at an early age. In Europe, the United States and other industrialized countries, on the other hand, the infection is mainly caused by susceptible young adults, most of whom are infected with the virus during visits to countries with high prevalence of the disease or by contact with infected persons contract.
HAV infection produces a self-limited disease that does not lead to chronic infection or chronic liver disease. However, it could be 10% -15% of patients experience recurrence of symptoms within 6 months after the acute illness. Acute liver failure in hepatitis is rare (overall mortality: 0.5%). The risk of symptomatic infection is directly related to age, with> 80% of adults with symptoms associated with acute viral hepatitis and the majority of children who are either asymptomatic or unrecognized infection. Antibodies to HAV infection continues to make to the life and confers protection against reinfection. Diseases can be prevented through vaccination, and hepatitis A vaccine has been proven worldwide in the control of outbreaks.