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INTRODUCTION

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Hepatitis is a systemic infection that predominantly affects the liver and is characterized by hepatic cell necrosis and mononuclear cell infiltration. The term “hepatitis” is conventionally reserved for “viral hepatitis” as most cases of hepatitis are caused by one of the five liver-specific (hepatotropic) viral agents: hepatitis A virus (HAV), hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV), and hepatitis E virus (HEV). All these human hepatitis viruses are RNA viruses except for HBV, which is a DNA virus. Other rare causes of hepatitis include infections with cytomegalovirus, Epstein-Barr virus, and herpes simplex virus, toxic chemicals, medication overdose, and autoimmune hepatitis.

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In the United States, viral hepatitis infections are mainly attributable to HAV, HBV, and HCV. Most acute infections are asymptomatic or cause only a mild self-limited disease, but progression to chronic disease with cirrhosis and liver cancer is possible. Up to 5.3 million people—2% of the US population—are living with chronic hepatitis B or hepatitis C. Thus, many individuals are unaware they have clinically silent HBV or HCV infections until developing cirrhosis, end-stage liver disease, and/or hepatocellular carcinoma. Hepatitis infections are more common than HIV/AIDS and each year about 15,000 people die from liver cancer or liver diseases related to hepatitis B and hepatitis C. Currently, viral hepatitis (mainly hepatitic C) is the leading cause of liver cancer and liver transplantation.1

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Viral hepatitis can affect pregnant women and cause significant morbidity on mothers and their infants. Although distinct in their molecular and antigenic properties, all hepatitis viruses produce similar illnesses. Advances in immunologic identification of the hepatitis viruses have led to clearer separation of the clinical diseases caused by each of these infections. The differences are noteworthy during pregnancy as health implications on mother and infant health varied significantly. Over the past decades the study of viral hepatitis has expanded with the emergence of new antiviral therapies, updates of vaccination guidelines, and better understanding of perinatal transmission of infection from mother to her neonate. The role of antiviral therapies in treating pregnant women with viral hepatitis and reducing the risk of perinatal transmission appears to be an achievable goal in the near future.

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EPIDEMIOLOGY

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Hepatitis A

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Hepatitis A infection is common worldwide and it is estimated that about 1.4 million cases of HAV infection occur each year. The most common source of infection is person-to-person contact (fecal-oral route). In developing countries with poor sanitary infrastructure and high infection rates, exposed children frequently develop immunity without presenting symptoms of disease and outbreaks are infrequent. In contrast, residents of developed countries with low levels of HAV infection have fewer opportunities in childhood for developing immunity, leading to populations of susceptible adults who are more likely to develop symptomatic disease if infected.2

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In the United States, implementation of infant vaccination since 1996 resulted in a progressive decrease in ...

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