Jaundice is the disease that your friends diagnose.
—Sir William Osler
The causes of hepatitis (inflammation of the liver) are varied and include viruses, bacteria, and protozoa, as well as drugs and toxins (eg, isoniazid, carbon tetrachloride, and ethanol). The clinical symptoms and course of acute viral hepatitis can be similar, regardless of etiology, and determination of a specific cause depends primarily on the use of laboratory tests. Hepatitis may be caused by at least five viruses, including hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV) belonging to different virus families, whose major characteristics are summarized in Table 13–1. Non-A, non-B hepatitis is a term previously used to identify cases of hepatitis not due to HAV or HBV. With the discovery of HCV and HEV, virtually all the viral etiologies of non-A, non-B hepatitis can be specifically identified. One additional hepatitis virus, hepatitis G virus (HGV) or GB virus C (GBV-C), has been identified that is not associated with any clinical disease so far but found in some blood donors as well as some patients who are either infected with HCV or human immunodeficiency virus (HIV). Other viruses, such as Epstein-Barr virus and cytomegalovirus, can cause inflammation of the liver, but hepatitis is not the primary disease caused by them. Yellow fever virus is also associated with hepatitis, but is described in Chapter 16.
TABLE 13–1Comparison of Hepatitis A, B, D (Delta), C, and E ||Download (.pdf) TABLE 13–1 Comparison of Hepatitis A, B, D (Delta), C, and E
|FEATURE ||A ||B ||D ||Ca ||E |
|Virus type ||Single-stranded RNA (+) ||Double-stranded DNA ||Single-stranded RNA (–) ||Single-stranded RNA (+) ||Single-stranded RNA (+) |
|Incubation period (days) ||15-45 (mean, 25) ||30-180 (mean, 60-90) ||28-45 ||15-150 (mean, 50) ||15-60 (mean, 40) |
|Onset ||Usually sudden ||Usually slow ||Variable ||Insidious ||? |
|Age preference ||Children, young adults ||All ages ||All ages ||All ages ||Young adult |
|Transmission || || || || || |
| Fecal–oral ||+++ ||± ||± ||– ||+++ |
| Sexual ||+ ||++ ||++ ||+ ||+? |
|Parenteral ||– ||+++ ||++ ||+++ || |
|Chronicity (%) ||None ||10 ||50-70 ||85 ||Rare |
|Carrier state ||None ||Yes ||Yes ||Yes ||No |
|Immune serum globulin protective ||Yes ||Yesb ||Yesc ||No ||No |
|Vaccine ||Yes ||Yes ||Yesc ||No ||No |
HEPATITIS A Overview
Hepatitis A virus (HAV) is a positive-sense RNA, icosahedral naked capsid virus belonging to Picornavirus family, which replicates in the cytoplasm by using viral RNA-dependent RNA polymerase for transcription and replication. It is the cause of what was formerly termed ...