visits, referral to drug-treatment and harm-reduction programs, education about liver health, and prevention of transmission to others. Chapter 5 will discuss the components of viral-hepatitis services.
DISEASE-SPECIFIC ISSUES RELATED TO VIRAL-HEPATITIS SURVEILLANCE
Many of the difficulties that surveillance systems face in identifying and tracking cases of hepatitis B and hepatitis C are related to the complexity of the infections and their associated progression (see Figures 2-1 and 2-2). This section highlights some of those challenges. Chapter 5 will provide more detail on issues related to screening and identification.
FIGURE 2-1 Natural progression of hepatitis B infection.
Abbreviations: HBeAg, hepatitis B e antigen; anti-HBe, antibody to hepatitis B e antigen; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HCC, hepatocellular carcinoma.
aTransmission occurs in 90% of infants of HBsAg+/HBeAg+ mothers and 15% of infants of HBsAg+/anti-HBe+ mothers.
b30% of those infected from the age of 1–5 years and under 7% of those infected at the age of 6 years or older.
cAbout 50% of patients by 5 years and 70% of patients by 10 years will seroconvert to anti-HBe.
d15-25% risk of premature death from cirrhosis and HCC.