Facts on File Encyclopedia of Health and Medicine

percent of hepatitis cases in the United States and
hepatitis B for nearly 30 percent. Other identified
hepatitis viruses (HFV and HGV) are rare in the
United States. Hepatitis B and hepatitis C can be
present without showing symptoms; about a third
of people who have hepatitis B are carriers (the
virus is present in their bodies and infects others,
though does not cause illness in them). Though
health agencies routinely test donated BLOOD, tis-
sue, and organs for hepatitis (as well as numerous
other infectious agents), people who receive
donor substances face some risk of infection.
Hepatitis C accounts for about 80 percent of such
infections; new infections have become rare as a
result of stringent donor substances screening.
Hepatitis D can replicate only when hepatitis B is
also present. It often causes “superinfection”—

acute disease with chronic hepatitis B infection.

Hepatitis E occurs in outbreaks related to water

contamination, such as might follow widespread

flooding, and tend to be more common among

people who contract the virus during travel to

developing countries where COMMUNITY SANITATION

is inadequate.

Viral hepatitis begins with an acute illness that

lasts from 2 to 10 months, though in most people

the acute phase resolves in 4 to 6 months. Chronic

forms of hepatitis often follow infection with HBV

and HCV, resulting in recurring episodes of symp-

toms. The repeated inflammation is very harmful

to the liver, causing scarring (fibrosis) that eventu-

ally becomes CIRRHOSIS(SCARtissue replaces liver

tissue). The damage tends to be progressive, cul-

minating in liver failure in about 25 percent of

hepatitis 55

Hepatitis Virus Mode of Infection Preventive Measures

hepatitis A (HAV) fecal-oral vaccination
food-borne frequent HAND WASHINGand conscientious PERSONAL
person-to-person HYGIENE
occupational exposure postexposure prophylaxis

hepatitis B (HBV) blood vaccination
sexual contact safer sex practices
shared needles among illicit injected avoid sharing needles
DRUGusers barrier precautions to prevent occupational exposure
perinatal (to infant at birth) postexposure prophylaxis
hemodialysis
occupational exposure

hepatitis C (HCV) blood safer sex practices
sexual contact avoid sharing needles
shared needles among illicit injected barrier precautions to prevent occupational exposure
drug users postexposure prophylaxis
perinatal (to infant at birth)
hemodialysis
occupational exposure

hepatitis D (HDV) blood HBV vaccination (HDV can infect people only already
shared needles among illicit injected infected with HBV)
drug users avoid sharing needles
occupational exposure barrier precautions to prevent occupational exposure
postexposure prophylaxis

hepatitis E (HEV) fecal-oral boiling water when contamination is possible
water