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Hepatitis B Virus
Hepatitis B is a viral infection that affects the liver and can cause both acute and chronic disease. It is transmitted through bodily fluids and is preventable through vaccination. Acute hepatitis B usually clears up on its own within 6 months, while chronic hepatitis B can last a lifetime if left untreated. Complications of chronic hepatitis B include cirrhosis, liver cancer, and liver failure. Hepatitis B is a major global health problem and vaccination is the most effective way to prevent its spread.
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Hepatitis B Virus
- 1. Hepatitis B Virus HuzaifaHamid Ahmad Peshraw Karim Abdurrahman Shanyar Kadir Hamakarim Shkar Dilshad Abdulkarim Shvan Omar Siddiq
- 2. Causes of Hepatitis: drugs toxins alcohol viralinfections (A, B, C, D, E) other infections (parasites, bacteria) physical damage What is hepatitis?
- 3. Functions Stores sugar neededfor energy Absorbs good nutrients Breaks down poisons (toxins) and drugs Makes important proteins that help build new tissue and repair broken tissue Produces bile, which helps remove waste from the body Liver
- 4. Acute Hepatitis: Short-termhepatitis. Body’s immune system clears the virus from the body within 6 months Chronic Hepatitis: Long-term hepatitis. Infection lasts longer than 6 months because the body’s immune system cannot clear the virus from the body Hepatitis Terms
- 5. Hepatitis B Virus CDCwebsite: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_1.htm
- 6. What is it? HepB is a serious disease caused by a virus that infects the liver Can cause lifelong infection, cirrhosis (liver scarring), liver cancer, liver failure and death Hepatitis B
- 7. Family: Hepadnaviridae Hepa: forliver Dna: for Deoxyribonucleic acid Virion (aka Dane particle): Outer lipid envelope Icosahedral nucleocapsid core composed of protein Outer envelope proteins: Binding & entry into susceptible cells Size: small, 42 nm in diameter Structure
- 9. Circular DNA Unusual, partiallydouble stranded Long strand: 3020–3320 nucleotides Short strand: 1700–2800 nucleotides One end of the long strand is linked to the viral DNA polymerase Genome
- 11. Nomenclature for HepatitisB Virus components
- 12. Hepatitis B Virion,Dane particle and HBsAG
- 13. Reverse transcription: oneof the mRNAs is replicated with a reverse transcriptase making the DNA that will eventually be the core of the progeny virion RNA intermediate: HBV replicates through an RNA intermediate and produces and release antigenic decoy particles. Integration: Some DNA integrates into host genome causing carrier state HBV: Replication
- 14. Clinical outcomes ofHepatitis B infections From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 62, published by Mosby Philadelphia,,
- 15. Determinants or acuteand chronic HBV infection From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia,,
- 16. Child-to-child Contaminated needles Sexual contacts Healthcareworker Blood transfusion • 6% of people infected over the age of 5 become chronically infected Perinatal • 90% of infected infants become chronically infected Perinatal transmission Horizontal transmission Transmission of HBV CDC. Available at: http://www.cdc.gov/hepatitis. Accessed December 2006. Lee WM. N Engl J Med. 1997;337:1733-1745. Lavanchy D. J Viral Hepat. 2004;11:97-107. HostMother Infant Recipient
- 17. Hepatitis B isNOT transmitted through food/water. Hepatitis B is NOT transmitted through casual contact such as hugging or shaking hands. Hepatitis B is NOT transmitted through kissing, sneezing or coughing. Hepatitis B is NOT transmitted through breastfeeding. What are some common myths and misconceptions about Hepatitis B?
- 18. Diagnostic tests HBsAg HBeAg HBV-DNA HBcAb IgM HBcAb IgG HbsA b IgG Acute infection+ + - - Prior infection - - + + Chronic infection- carrier + + + - Immunizat ion - - - + Windo w period only HBc Ab is +
- 19. Hepatitis B acuteinfection CDC website: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_3.htm Note: Pattern of serological markers varies depending on whether the infection if acute or chronic
- 20. Chronic Hepatitis Binfection http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_b/slide_4.htm Notes: In patients with chronic HBV infection, both HBsAg and IgG anti-HBc remain persistently detectable, generally for life. HBeAg is variably present in these patients. The presence of HBsAg for 6 months or more is generally indicative of chronic infection. In addition, a negative test for IgM anti-HBc together with a positive test for HBsAg in a single serum specimen usually indicates that an individual has chronic HBV infection.
- 21. Injection drug users Sexpartners of those with Hep B Sex with more than one partner Men who have sex with men Living with someone with chronic Hep B Contact with blood Transfusions, travel, dialysis Who is at highest risk?
- 22. Prevent perinatal HBVtransmission Routine vaccination of all infants Vaccination of children in high-risk groups Vaccination of adolescents Vaccination of adults in high-risk groups Prevention
- 23. Composition Recombinant HBsAg Efficacy95% (Range, 80%-100%) Duration of Immunity 20 years or more Schedule 3 Doses Booster doses not routinely recommended Hepatitis B Vaccine
- 24. Nausea Loss of appetite Vomiting Fatigue Fever Darkurine Pale stool Jaundice Stomach pain Side pain Symptoms A person may have all, some or none of these
- 25. FDA approved Interferon Alfa Lamivudine– reverse transcriptase inhibitor Adefovir – nucleotide analogue that inhibits viral polymerase Investigational Tenofovir – adenine nucleotide analogue Approved for HIV Entecavir – guanosine analogue, highly selective for the HBV polymerase Treatment options
- 26. 1/3 of world’spopulation has been infected 350 million with chronic disease 15-25% of these die due to liver related diseases 1 million deaths annually United States 1.25 million chronic carriers 5000 deaths annually Hepatitis B epidemiology Figure 66-9. Worldwide prevalence of hepatitis B carriers and primary hepatocellular carcinoma. (Courtesy Centers for Disease Control and Prevention, Atlanta.)
- 27. Notes: HDV infection canbe acquired either as a co-infection with HBV or as a superinfection of persons with chronic HBV infection. Persons with HBV-HDV co-infection may have more severe acute disease and a higher risk of fulminant hepatitis (2%-20%) compared with those infected with HBV alone; however, chronic HBV infection appears to occur less frequently in persons with HBV-HDV co-infection. Chronic HBV carriers who acquire HDV superinfection usually develop chronic HDV infection. In long-term studies of chronic HBV carriers with HDV superinfection, 70%-80% have developed evidence of chronic liver diseases with cirrhosis compared with 15%-30% of patients with chronic HBV infection alone. CDC website: http://www.cdc.gov/ncidod/diseases/hepatitis/slideset/hep_d/slide_1.htm
- 28. Key features ofHepatitis Delta Virus •Single stranded, self complementary RNA, encapsidated in HbsAg •Small, amorphous particle •RNA encodes one protein: delta antigen •Replicates via RNA directed RNA synthesis, catalyzed by host RNA polymerase II
- 29. Key features ofHepatitis Delta Virus •Delta antigen required for replication, role unknown •Dependent on HBV as a “helper” •HBV provides HbsAg •May be acquired as co-infection with HBV, or superinfection of HBV infection •Exacerbates HBV induced disease
- 30. Hepatitis Delta Virion FromMurray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia,, Figure 66-14
- 31. Consequences of hepatitisB and delta virus infection Figure 66-15. Consequences of deltavirus infection. Deltavirus (d) requires the presence of hepatitis B virus (HBV) infection. Superinfection of a person already infected with HBV (carrier) causes more rapid, severe progression than co-infection (shorter arrow). From Murray et. al., Medical Microbiology 5th edition, 2005, Chapter 66, published by Mosby Philadelphia.
- 32.