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Hepatitis B virus

Hepatitis B virus. Hepatitis viruses: A B formerly serum hepatitis C D non A nonB E G. One of the most prevalent infections. Worldwide: 2 out of 6 billion encountered with HBV 350–400 million CHB cases - 4 million new cases/year - >1 million deaths/year. HBV.

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Hepatitis B virus

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  1. Hepatitis B virus Hepatitis viruses: A B formerly serum hepatitis C D non A nonB E G

  2. One of the most prevalent infections Worldwide: 2 out of 6 billion encountered with HBV 350–400 million CHB cases - 4 million new cases/year - >1 million deaths/year

  3. HBV • Hepadnavirus • semi (relaxed) circular 3.2 kb ds DNA • Encodes 7 polypeptides • Large amounts of of HBs is released from infected cells • HBV genome integrates to host cell chromosome

  4. Proteins: 4 ORF • Two structural proteins: HBs and HBc/HBe • Polymerase • X protein • 3 initiation codons for S: L, M, S • 2 inititions codons for C: HBc+e

  5. S protein contains common antigenic determinan “a” • Phenotypes of HBs: adw, ayw*, adr and ayr – 8 serotypes

  6. In serum with EM: • Spherical particles 22 nm • Tubuler of filamentous 200 nm long • Spherical virions 42 nm (Dane particle)

  7. Replication • Attachment and uncoating • cccDNA formation in nucleus • cccDNA  3.5 kb pregenomic RNA • Pregenomic RNA is encapsidated with new HBc and + sense DNA is produced by reverse transcription in Golgi

  8. Transmission: Through blood and body fluids (semen, saliva, milk, vagina, menstruel secretions and amniotic fluids • Vertical transmission • Incubation period min 6 weeks

  9. 1/3 of world pop. Has serologic evidence350 M chronically infectedHBV related HCC >1 M deaths and 5-10 % liver transplantations

  10. High-Risk Groups for Hepatitis B Virus • People from endemic regions (i.e., China, parts of Africa, Alaska, Pacific Islands) • Babies of mothers with chronic hepatitis B virus • Intravenous drug abusers • People with multiple sex partners, homosexual and heterosexual • Hemophiliacs and other patients requiring blood and blood product treatments • Health care personnel who have contact with blood • Residents and staff members of institutions for the mentally retarded • Hemodialysis patients and blood and organ recipients

  11. Chronic hepatitis B 1. HBsAg-positive 6 months 2. Serum HBV DNA 20,000 IU/mL (10 5copies/mL), lower values 2,000- 20,000 IU/mL (10 4-10 5 copies/mL) are often seen in HBeAg-negative chronic hepatitis B 3. Persistent or intermittent elevation in ALT/AST levels 4. Liver biopsy showing chronic hepatitis with moderate or severe necroinflammation

  12. Resolved hepatitis B 1. Previous known history of acute or chronic hepatitis B or the presence of anti-HBc anti-HBs 2. HBsAg 3. Undetectable serum HBV DNA* 4. Normal ALT levels *Very low levels may be detectable using sensitive PCR assays

  13. Serologic markers of HBV

  14. IFN-alpha • LAmivudin • Entacavir • Adefovir • Tenofovir • Telbivudin

  15. Hepatitis D

  16. HDV prevalence in Turkey CHB n = 5961 20 %  1980-1990 31 %  1991-2000 19.4 %  2001-2005 11 % Cirrhosis n= 264 32.5 %  1980-1990 43.5 %  1991-2000 26.1 %  2001-2005 24 % (

  17. Viroid • HBV dependent • 1700 bp ss RNA • HBsAg envelope • Cellular RNA pol II copies genomik RNA  Ribozyme  cleaves circular RNA into mRNA for small delta ag

  18. Delta ag gene is mutated by celular ds RNA activated adenosine deaminase enzyme which allows large delta ag production.

  19. Percutaneous • Blood and blood product transfusion kan ve faktör • Person-person • Open lesions of the skin

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