Viral hepatitis is an infection that causes impaired liver function. The three main types of viral hepatitis include hepatitis A (HAV), hepatitis B (HBV), and hepatitis C (HCV). Hepatitis A is transmitted through fecal-oral contact and is often spread by food handlers but can also be spread through anal-oral contact. In the United States, hepatitis A is the most frequent vaccine-preventable disease (Centers for Disease Control and Prevention, 2005e). Hepatitis B is predominantly spread during high-risk sexual behaviors (see Sex in Real Life, “High-Risk Sexual Behaviors,” on page 495; Kellerman et al., 2003). Although hepatitis C can be spread through sexual behavior, it is mostly caused by illegal intravenous drug use or unscreened blood transfusions.
Incidence One-third of Americans have evidence of a past infection with hepatitis A (Centers for Disease Control and Prevention, 2005e; see Figure 15.9 for more information on hepatitis infection rates). Although 10,609 HAV cases were reported in 2001, because of underreporting researchers estimated this number was closer to 45,000 (Centers for Disease Control and Prevention, 2005e). Historically rates for HAV have varied by ethinicity, with higher rates in Native Americans and Alaskan Natives. However, this was probably due to increased contact with people from countries with higher HAV rates (such as Mexico and Central America) and socioeconomic and living conditions.
There are approximately 1.25 million people infected with hepatitis B in the United States, and another 78,000 become infected every year (Centers for Disease Control and Prevention, 2005d). A total of 3.9 million Americans have been infected with hepatitis C, and close to 70% are chronically infected (Centers for Disease Control and Prevention, 2005e).
Symptoms Symptoms of hepatitis A usually occur within 4 weeks after a person is infected and include fatigue, abdominal pain, loss of appetite, and diarrhea. Hepatitis A has no chronic long-term infection. Symptoms of hepatitis B usually occur anywhere from 6 weeks to 6 months after infection, although infection with hepatitis B is usually asymptomatic. Possible symptoms may include nausea, vomiting, jaundice, headaches, fever, a darkening of the urine, moderate liver enlargement, and fatigue. It is estimated that 15% to 25% of those infected with hepatitis B will die from chronic liver disease (Centers for Disease Control and Prevention, 2005e). Finally, most people infected with hepatitis C are asymptomatic or have a mild illness and develop this illness within 8 to 9 weeks. The Centers for Disease Control and Prevention estimate that between 75% and 85% of those infected with hepatitis C will develop a chronic liver infection.
Diagnosis Blood tests are used to identify viral hepatitis infections.
Treatment At this time there are three drugs licensed for hepatitis; these drugs have been found to be effective (Marcellin et al., 2003). These therapies have been designed to reduce viral load by interfering with the life cycle of the virus and also causing the body to generate an immune response against the virus (Guha et al., 2003). Healthcare providers generally recommend bed rest and adequate fluid intake so that a person doesn’t develop dehydration. Usually after a few weeks an infected person feels better, although this can take longer in persons with severe infections.
Vaccines are available for the prevention of both hepatitis A and B, and persons at high risk of contracting either of these should have the vaccine. High-risk individuals include healthcare workers who may be exposed to blood products, intravenous drug users and their sex partners, people with multiple sexual partners, people with chronic liver disease, and housemates of anyone with hepatitis (Centers for Disease Control and Prevention, 2005e; K. Miller & Graves, 2000). Men who have sex with men should also be vaccinated against HAV and HBV (C. Diamond et al., 2003). A vaccine for hepatitis C is urgently needed, and research is ongoing to find one.