1. Hepatitis viruses. Features of structure and main biological properties Vinnitsa National Pirogov Memorial Medical University / Department of microbiology

2.  The term “viral hepatitis” refers to a primary infection of the liver by any one of a heterogeneous group of “hepatitis viruses”. It consists of types A, B, C, D, E, G.  Hepatitis viruses are taxonomically unrelated (DNA and RNA viruses). The features common to them are: 1. hepatotropism 2. ability to cause a similar icteric illness

3. By epidemiological and clinical criteria, two types of viral hepatitis had been recognised for long:  A first type (this type was called infective or infectious hepatitis) 1. Occurred sporadically or as epidemics; 2. Affecting mainly children and young adults; 3. Transmitted by the fecal-oral route.  A second type (this type had been given various names such as serum hepatitis or transfusion hepatitis) transmitted mainly by parenteral route

4. Type A virus hepatitis (HAV)  Belongs to the Picornaviridae family  Morphology. 1. HAV is a spherical ss(+)RNA- including virus 2. 27-30 nm in diameter 3. Non enveloped

5. Classification of viral hepatitis  Hepatitis A virus  Hepatitis B virus  Hepatitis C virus  Hepatitis D virus  Hepatitis E virus  Hepatitis G virus

6. HAV is transmitted by the fecal-oral route Pathogenesis  The clinical disease consists of two stages: the prodromal (or preicteric) and the icteric stage

7. Laboratory diagnosis 1. IEM 2. Serology 3. Detection of viral antigens in stool samples

8. Prophylaxis  General prophylaxis consists of:  Specific prophylaxis 1. Active 2. Passive Treatment is symptomatic. No specific antiviral drug is available

9. Type B hepatitis (HBV)

10. Antigen Structure  HBsAg  HBcAg  HBeAg  HBxAg

11. There are three important modes of transmission of HBV infection: parenteral, perinatal, sexual Laboratory diagnosis Detection of hepatitis B antigens and antibodies (viral markers). Detection of hepatitis B antigens and antibodies (viral markers).

12. Prophylaxis  Prophylaxis includes:  General preventive measures  Immunisation 1. Passive 2. Active.

13. Type C hepatitis (HCV)  Hepatitis C virus belongs to the family Flaviviridae  HCV is a 50-60 nm virus with a linear single stranded RNA of positive polarity (ss(+)RNA)  Enclosed within a core and surrounded by an envelope, carrying glycoprotein spikes

14. Laboratory diagnosis  It can be established by detection of anti-HCV by ELISA.  Viral genome (HCV RNA) detection

15. Type D (Delta) hepatitis (HDV)  HDV is a defective RNA virus depending on the helper function of HBV for its replication and expression. It belongs to genus Deltavirus

16. Its mode of transmission is the same as for HBV  Two types of infection are recognized 1. Coinfection 2. Superinfection

17. Laboratory diagnosis  Delta antigen  Anti-delta antibodies