Overview of the Etiologic Agent
Viral hepatitis is an acute and/or chronic liver
disease caused by several etiologic agents. The
term "hepatitis" refers to inflammation of the
liver; viruses are only some of the current
causes of hepatitis, and will be the focus of
this section.
Five types of viral hepatitis are currently
known, and they are hepatitis A virus (HAV),
hepatitis B virus (HBV), hepatitis C virus (HCV),
HBV-associated delta agent or hepatitis D virus
(HDV), and hepatitis E virus (HEV). Each virus
causes liver disease of a different course and
outcome, some mild to moderate, others terminal
and life threatening.
The study of viral hepatitis is extensive and
will be discussed here only with regards to its
transmission and prevention sexually.
HAV and HEV are transmitted by the oral-fecal
route, and so are primarily acquired through
ingestion of contaminated food and water
supplies. However, sexual activity that includes
anal sex may lead to contamination via this
route. HBV, and its associated HDV, are
transmitted through exposure to blood, blood
products and bodily fluids, and sexual activity
is known to contribute to their transmission.
The mode of transmission of HCV is believed to be
largely through blood exposures, but since a
certain proportion of HCV-infected individuals
lack any history of blood exposures, the
transmission of HCV is considered to be unproven
but possible.
As with all viruses, there are no cures for the
illnesses, only treatment for their symptoms as
well as attempts to lessen the concentration of
the virus in the blood. Prevention includes the
avoidance of risky behaviors, including
unprotected sex. Vaccines for HAV and HBV exist
and are effective. HBV vaccination is now a
routine vaccination for children in the U.S., but
was only fairly recently implemented as a routine
childhood vaccine. HBV vaccination is indicated
for sexually active men and women, homosexual,
bisexual and heterosexual, as well as injection
drug users and persons in high-risk professions
(i.e. medical or laboratory workers who handle
bodily fluids.) HAV vaccination is usually
reserved for persons traveling to countries with
unreliable water and food supplies, but is also
recommended for people in the U.S. who use
injection drugs and for men who have sex with
men.
