HBV

Question 1

Pathogenesis

Answer 1

1) Long incubation hepatitis

2) blood and all other fluid transmission

Question 2

Pathogenesis : Antigen

Answer 2

• HBs –> detectable in blood –> causes hyper 3 reaction
• super capsid with : L, M, &S Ag
• HBc - on capsid not detectable in blood
  -HBe- dissolved in blood if high reproduction dates ( acute viremia)
  Not related to structure. Sign of acute &infectious stadium of diseases ( marker of acute phase )

Question 3

Pathogenesis : incomplete HBs Ag & complete( intact)

Answer 3

• in blood 10^5- 10^9 virions/ml –> high conc
• 22nm diameter sphereical- numerous
• 200 tubular : filamentous–> overproduction of HBsAg

Complete : Dane particle- 42nm diameter

Question 4

Pathogenesis : resistance

Answer 4

• very high!! -> 100•c for 5 minutes and HBsAg very high

Question 5

Pathogenisis: epidemiology

Answer 5

• worldwide /300k: year in USA
• 4000 die/ year
• 90%transmission rate during pregnancy of HBeAg are found

Question 6

Virus

Answer 6

Hepatnaviridae

Only DNA virus only circular

Question 7

Disease ( incubation, prodrome, icterus, transmission)

Answer 7

• IP: 2-6months, depends in dose, transmission and cellular immunity
• Prodrome: 1 week
• Icterus(4:1) after after 7-11days
• Transmission : via blood , sex, transplacental or breast milk
• tropism to hepatocytes (90%infected) attached via viral gap –> transcription in nucleus ( integrates into genome of hepatocytes –> budding

Question 8

Disease: (cell mediated immunity, chronic active hepatitis, chronic or asympt,

Answer 8

1) cell mediated immunity–> effectively decides if acute or fulminant (rapid severe acute form)
2) chronic active hepatitis ( continued acute hepatitis)
3) chronic or asymptomatic (no AB, but also no injury –> carrier state ( often in immonosuppressed people) can cause cirrohosis or hepatocellular carcinoma( due to viral DNA incorporated into host DNA, leading to growth factor formation)
- acute markers: HBeAg &HBsAg
- recovery markers: anti-HBe

Question 9

Disease: extra hepatic symptoms

Answer 9

• Arthalgia
• vasculitis
• rash (glomerulonephritis)
• kidney destruction ( in immunity compromised children)

Question 10

Diagnostic

Answer 10

• PCR
• ELISA
• WESTERN BLOT
• High AG level can cover AB level ( but Ab are actually there)

Question 11

Treatment and immunity

Answer 11

1) formalin inactivated vaccine
- HBsAg of 22nm particles from healthy carriers get purified
2) Recombinant DNA - derived vaccine
- HBsAg produced by recombinant DNA in yeast- 15-30 nm
- not dangerous ( only protein and envelope )
- given to all children (2.4 or 15 months)
- booster shots in adolescence
3) passive immunisation HBIG
- give immediately after exposure ( in 3 days )
4) interferon alpha treatment suppresses HBC DNA

Question 12

Structure

Answer 12

• Serum hepatitis
• 42 nm diameter ( quite big)
• envelope ( HBs AG protein spikes)
• spherical virions
• icosahedral nucleocapsid core (HBc Ag)
• partially ds and ss circular DNA
• DNA give a higher risk for cancer than RNA
• DNA polymerase