This document summarizes information about viral hepatitis, with a focus on hepatitis C. It discusses the discovery of hepatitis B and hepatitis C viruses, the clinical manifestations of hepatitis C infection, diagnostic tests for hepatitis C including antibody and RNA tests, natural history and progression of hepatitis C disease, and treatment recommendations for chronic hepatitis C. Epidemiological data on hepatitis C prevalence globally and in Thailand is also presented.

5. Sources of infection (CDC USA)

7. Serologic pattern of HCV infection

11. Anti HCV test ; A: EIA B: RIBA A B

12. Interpretation of Anti-HCV Test Anti-HCV Anti-HCV HCV-RNA Interpretation EIA RIBA Positive Positive Positive Current infection Positive Positive Negative Intermittent viremia or resolved infection Positive Negative - Uninfected Negative - - Uninfected Positive Indeterminate Negative False positive anti HCV test Positive Indeterminate Positive *Recent HCV infection *Persistent finding in some chronic HCV

13. Anti HCV screening test, RIBA and HCV RNA result In groups with different HCV prevalence HCV prevalence Total test No(%) RIBA result(%) HCV RNA positive Neg Ind. Pos positive (%) 0.8-4.4% 24,012 689 27 7 66 41* 9.5% 2,936 351 10 7 83 80 24.9% 498 124 2 4 94 NA+ *: only 214 sample were test for HCV RNA *: Not assess

14. Treatment of Chronic Hepatitis C Indication : ALT level >1.5 x upper normal limit on three consecutive occasions ≥ 3 months : Liver Bx indicate active disease Regimen : Combination of Interferon alpha 3 MU TIW and ribavirin 1000-1200 mg/d x 24 weeks for genotye 2 and 3 and 48 weeks for genotype 1 Successful treatment : clearance of HCV RNA from serum 6 month after therapy