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.