Hepatitis A through E.

Viral hepatitis is a term commonly used for several clinically similar, yet etiologically and epidemiologically distinct, diseases. Five human hepatitis viruses have been identified. Hepatitis A, B, C, and D are endemic in the United States; hepatitis E is rarely reported in the United States, and most U.S. cases are seen in persons who have traveled to areas where hepatitis E. is endemic. Hepatitis A and E are transmitted by the fecal-oral route; hepatitis B, C, and D are blood-borne diseases. Hepatitis A and B have been recognized as separate entities since the early 1940s and can be diagnosed by serologic tests. Tests are available to detect the antibody to hepatitis C and D virus; no commercial test is available to diagnose hepatitis E. Hepatitis A, B, and D can be prevented by vaccine, but no vaccines are available for hepatitis C or E.