Hepatitis B Virus (HBV) Flashcards
What is hepatitis?
Inflammation of the liver (macrophages & eosinophils)
What can cause Hepatitis?
bacteria parasites viral Alcohol (Non-infect.) Drugs (Non-infect.)
When was Hepatitis B discovered?
1965
What are the types of Viral Hepatitis?
A (fecal-oral transmission) B (blood/ blood derived fluid) C D E
Who is at risk of HBV chronic disease?
80-90% of infants infected during first year of life develop.
15-25% of adults become chronically infected during childhood die from hep-B related liver cancers or cirrhosis.
How is HBV transmitted?
Exposure to infectious blood (tattooing, dialysis)
Body fluids (semen & vaginal fluids)
Perinatal infection
How much more infectious is HBV to HIV?
50-100 times because HIV dies if outside body after 7 hours where as Hep B can survive up to 10 days.
What is the structure of HBV?
Circular genome of partially double stranded DNA. Cannot cell culture virus Double shelled particles DNA virus 42 nm diametre
What is the mechanism for transfection?
1) virus enters hepatocyte (liver cell)
2) uncoating (lipid bilayer removed)
3) nuclear transport (translocation from cytoplasm to nucleus)
4) repairing partially double stranded genome
5) synthesis of genomic HBV RNA
6) viral translation occurs
7) RT leads to negative DNA
8) positive DNA strand synthesis
9) viral assembly takes place in ER
10) nucleocapsid coating with envelope proteins
11) budding and viron secretion into blood.
What are the symptoms of acute HBV?
itchy skin, vomitting, fatigue, anorexia, nausea, mild fever, dark urine, after 45-160 day incubation.
Can be asymptomatic (more common in children)
Can result in fulminate hepatic failure.
Define serology
Science that deals with antigen-antibody reaction
What are the two main antibodies for acute HBV?
IgG
IgM
How can you prevent HBV?
avoid unprotected sex
do not share needles
vaccine recommend to all UK travellers that could be at risk
Hep B immunoglobulin used to protect person who are exposed to HBV efficacious within 48hr incident.
What are the guidelines for pregnant women?
should be tested for Hep B
If positive, in delivery room = Hep B vaccine and HB immune globulin.
If the two medications given correctly within first 12 hours of life = newborn has 95% chance of being protected.
How do you test for HBV?
blood tests- whether immune, infectious, have it.
