Viral hepatitis I Flashcards
What is hepatitis and what causes it?
hepatitis = inflammation of the liver
causes:
- toxins and chemicals (e.g. alcohol)
- autoimmune diseases
- fat
- viruses
What is the main laboratory test for hepatitis?
looking for elevated liver enzymes - ALT
why is chronic hepatitis a problem?
- very common
- often without symptoms until late in the disease when the patient is developing cirrhosis or liver cancer
Describe the morphology of HAV
- +ssRNA
- picornaviridae; hepatovirus
- nonenveloped
What is HAV route of transmisson?
- fecal-oral
- contamination of food
- poor hygiene
- inadequate sewer treatment
What is the clinical course of HAV?
- subclinical or acute
- short duration
- elevated ALT
- rarely causes chronic disease
What are some HAV prevention techniques?
- good hygiene
- passive immunity
- vaccine
- no antiviral agents
Describe the morpholgy of HBV
- partially dsDNA
- hepadnavirus family
- subviral particles –> sausage shaped
- dane particles -> donut shaped
Describe HBV genes
- HBsAg (S, M, L) - surface
- HBcAg - capsid
- viral pol
- x protein
Describe HBV lifecycle
entry –> uncoating –> repair DNA –> cccDNA (responsible for persistance) –> integration –> ts –> tl –> assembly –> exit
What is the mortality rate trend of hepatitis?
deaths are continuing to rise!
What is HBV’s route of transmisson?
- horizontal
- blood
- IV drug use
- sexual transmisson - vertical
Are females or males more at risk of developing liver death from HBV?
males
When are you most susceptible to becoming an HBV chronic carrier, how does this change with age?
- most susceptible at birth
- as you age youre less likely to become chronic carrier after being infected
What are the consequences of HBV for chronic carriers
- asymptomatic
- cirrhosis
- hepatoma
What are the top two leading causes of liver disease?
- smoking
- HBV
What is the major cause of HCC worldwide?
HBV
What is the serological response to infection with HBV: acute and chronic?
acute:
- HBsAg appears
- peaks over several weeks
- disappears with the appearnace of HBsAb
chronic:
- HBsAg appears and remains
- do not have detectable HBsAb in serum
What are the vaccine strategies for HBV
- pre-exposure - select high risk groups
- post-exposre - needle accidnts, sexual exposure, babies born to HBV
- universal immunization - best
How does HBV vaccination affect the incidience of HCC?
universal HBV vaccination significantly decreases HCC incidence
What’s a big problem for the development of antiviral therapy for HBV?
development of an animal model - duck model was eventually used
What nuceloside analog works well for HBV, which one doesn’t work? How does it work?
works = ddG –> prevents proofreading
doesn’t work = ddC
What was the first oral antivrial for HBV, what did it cause?
first antiviral = Lamivudine
- decreases HBV load in serum
- regresses HBV cirrhosis
- re-opened the possibility of liver transplants
- developed antiviral resistance
What antivirals are used for HBV today? Why?
tenofovir and entecavir - potent and have very low rates of resistance
