hepatitis b virus
TRANSCRIPT
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Done by: Ahmad Mhd Al-dhlawiy Hamad Emad Dhuhayr
+Contents …
General concepts for hepatitis. Types of hepatitis. HBV Structure & Antigens. Transmission \Epidemiology. Pathogenesis & Immunity. Clinical pictures. Laboratory Diagnosis. Treatment \Prevention. References.
+ General Concepts …
VIRAL HEPATITIS :- is a serious disease caused by virus that attacks the liver . There are various strains of viral hepatitis which can cause lifelong infection, cirrhosis ( scarring) of the liver ,
liver cancer , liver failure, and death.
six medically important viruses are commonly described as “hepatitis viruses”:
HAV,HBV,HCV,HDV,HEV,HGV
+Terms for Hepatitis ….
Acute: Short term and/or severe.
Chronic: Lingering or lasting - may or may not be severe
Fulminant: Developing quickly and lasting a short time, high mortality rate.
Cirrhosis: Hardening: may be the result of infection or toxins (e.g. alcohol)
Jaundice: Yellowing of the skin, eyes, etc due to raised levels of bilirubin in the blood due to liver damage.
Hepatocellular carcinoma: is closely associated with hepatitis B, and at least in some regions of the world with hepatitis C virus.
+Viral hepatitis …
+Viral hepatitis …
+ HBV Structure & Antigens
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HBsAg = surface (coat) protein ( 4 phenotypes : adw, adr, ayw and ayr)
HBcAg = inner core protein (a single serotype)
HBeAg = secreted protein; function unknown
+Replication…
+Modes of Transmission for HBV Parenteral - IV drug abusers, health workers are
at increased risk.
Sexual - sex workers and homosexuals are particular at risk.
Perinatal - (Vertical) - mother(HBeAg+) →infant.
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+Incidence of Hepatitis in KSA
+High-risk groups for HBV infection
People from endemic regions Babies of mothers with chronic HBVIntravenous drug abusersPeople with multiple sex partnersHemophiliacs and other patients requiting blood
and blood product treatmentsHealth care personnel who have contact with
blood
+Concentration of Hepatitis B Virus in Various Body Fluids …
High ModerateLow/Not
Detectable
blood semen urineserum vaginal fluid feces
wound exudates saliva sweat
tearsbreastmilk
+Pathogenesis & Immunity … Virus enters hepatocytes via blood
Immune response (cytotoxic T cell) to viral antigens expressed on hepatocyte cell surface responsible for clinical syndrome
5 % become chronic carriers (HBsAg> 6 months)
Higher rate of hepatocellular ca in chronic carriers, especially those who are “e” antigen positive
Hepatitis B surface antibody likely confers lifelong immunity (IgG anti-HBs)
Hepatitis B e Ab indicates low transmissibility
+Clinical pictures …
+Possible Outcomes of HBV Infection
Acute hepatitis B infection
Chronic HBV infection
3-5% of adult-acquired infections
95% of infant-acquired infections
Cirrhosis
Chronic hepatitis
12-25% in 5 years
Liver failure Hepatocellular carcinoma
Liver transplant
6-15% in 5 years 20-23% in 5 years
DeathDeath
+Acute Hepatitis B Infection
+Laboratory Diagnosis …
+Treatment …
Interferon alfa (Intron A) ( Response rate is 30 to 40%.
Lamivudine (Epivir HBV)
(relapse ,drug resistance)
Adefovir dipivoxil (Hepsera)
+ Prevention …
Vaccination - highly effective recombinant vaccines.Hepatitis B Immunoglobulin (HBIG) -exposed within 48 hours of the incident/
neonates whose mothers are HBsAg and HBeAg positive.
Other measures -screening of blood donors, blood and body fluid
precautions.
+Hepatitis B Vaccine
Infants: several options that depend on status of the mother If mother HBsAg negative: birth, 0-2m,4-6m If mother HBsAg positive: vaccine and Hep B immune
globulin within 12 hours of birth, 1-2m, <6m
Adults * 0,1, 6 months
Routine booster doses are NOT routinely recommended for any group
Vaccine recommended in All those aged 0-18 Those at high risk
+References
website
http://www.hepatitis-central.com/hbv/hepbfaq/viroligy.html
http://en.wikipedia.org/wiki/Hepatitis_B
http://www.who.int/mediacentre/factsheets/fs204/en/index.html
http://www.cdc.gov/vaccines/pubs/vis/downloads/vis-hep-b.pdf
http://www.worldhepatitisalliance.org/AboutViralHepatitis/Prevention_Diagnosis_Treatment.aspx
http://emedicine.medscape.com/article/177632-overview
Text books
Richard A, HARVEY, Pamela C,Champe, Bruce D, Fisher. Microbiology 2nd edition. Lippicott Williams & wilkins. Chapter 26. PP(273-282)
Raphael Rubin, David S. Strayer. Rubin’s pathology 5th edition. Lippicott Williams & wilkins. Chapter 14. PP(637-640)
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AHMED AL DAHLAWY
HAMAD EMAD THUHAYR