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BDS2 BAMS lectures > Hepatitis viruses > Flashcards

Hepatitis viruses Flashcards

1
Q

Transmission of Hep A

A

faecal-oral

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2
Q

Clinical features of Hep A

A 
incubation period = 2-7 days
many subclinical infections
illness usually brief and self limiting
mortality <0.2%
no chronic disease
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3
Q

Diagnosis of Hep A

A

HAV antigen in faeces

detection of IgM anti-HAV

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4
Q

Immunisation for Hep A?

A

Yes

Human normal Ig = short term protection

Vaccine - single dose = antibody for 1 year, booster = immunity for 10 years

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5
Q

how many new hep B cases occur among people between ages 15-39

A

70%

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6
Q

How much more infectious is Hep B than HIV

A

100 times

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7
Q

Is there a vaccine available for Hep B

A

yes

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8
Q

Is there a cure available for Hep B

A

no

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9
Q

What type of virus is Hep B

A

partially double stranded DNA virus

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10
Q

What family of viruses does Hep B belong to

A

hepadnavirus

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11
Q

How many subtypes of Hep B exsist

A

8

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12
Q

What is a dane particle

A

the intact virus (viral coat + DNA genome)

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13
Q

What are the important antigens to know on Hep B

A
  • Hepatitis B surface antigen (HBs Ag)

- Hepatitis Be antigen (HBe Ag)

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14
Q

If someone is hepatitis Be antigen positive what does this mean?

A

they have a very high viral load (very infectious)

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15
Q

What’s the geographical distribution of Hep B like?

A

mainly high in developing countries, lower prevalence in developed countries

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16
Q

How is HBV transmitted?

A
  • Bloodborne
  • Sexual
  • Perinatal (mother to child)
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17
Q

Why is perinatal transmission such a problem in endemic areas?

A

if contract as a child you are then a carrier so can pass to others and can lead to long term liver problems (cirrhosis and liver cancer)

(80-95% chronicity in endemic areas compared to 5% chronicity in non-endemic areas)

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18
Q

How is risk of chronic HBV infection affected by age of acquisition and immune status

A

neo nates 90-100%
children 20-40%
HIV positive 21%
adults <5%

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19
Q

What are the possible outcomes of exposure to Hep B virus

A

Infection (65% subclinical)

  • death (1%)
  • persistent infection (HBs Ag > 6 months) (5-9%)
  • Recovery with immunity (90-95%)

In this country, small number die, some become carriers (variet of things can happen after that), but most will recover

20
Q

What are the serological differences between someone who recovers from HepB and someone who develops a chronic infection

A

Recovery
once anti-HBe starts to form you are much less infective (about 3.5 months after exposure)

Chronic carriage
no antibodies developed to either HBs Ag or HBe Ag = risky patients

21
Q

How is passive immunity achieved with Hep B? When is it used?

A

Hep B Ig from pooled plasma

single acute exposure in non-immune individual (administer within 48hrs)

also used for non-responders to active vaccine following a sharps exposure

22
Q

how immunogenic is the HBV vaccine

A

highly immunogenic

23
Q

is a booster required, if so when? of the HBV vaccine

A

not required for responders of the HBV vaccine

24
Q

how is active immunity achieved for HepB

A

Hep B surface antigen (HBsAg) adsorbed on aluminium hydroxide adjuvant, produced by recombinant DNA technology

25
Q

What is the protection like of active immunity vaccine for Hep B

A

good protection

26
Q

What is the response like of active immunity vaccine for Hep B

A

response not always good so need to check antibody levels

27
Q

How is the active Hep B vaccine administered

A

intramuscular

28
Q

how many doses of the Hep B active vaccine do you need? when?

A

3 doses

time zero, one month, 6 months

29
Q

what is it important to do post immunisation of active HepB vaccine

A

test for antibody response 2-4 months after vaccination course complete

30
Q

what post exposure prophylaxis is required for Hep B

A

none for responders

Hep B Ig for non-responders (70-75% protection from infection)

31
Q

What is the goal for treatment of chronic HBV infection

A

sustained viral suppression

32
Q

What agents are avaliable to treat chronic HBV infections

A
  • immunomodulatory agents (IFN-alpha)
  • nucleoside analogues (Iamivudine, telbivudine, entecavir)
  • nucleotide analogues (adefovir and entecavir, these don’t cure but can really reduce viral load)
33
Q

What type of virus is Hep C

A

flavivirus

34
Q

How many genotypes of Hep C are there

A

6

35
Q

Is there a vaccine avaliable for Hep C

A

no

36
Q

How many genotypes of Hep B are there

A

1

37
Q

What does a Hep C virus look like

A

Enveloped RNA virus

38
Q

How is Hep C transmitted?

A
  • IV drug use
  • blood and blood products
  • organ/tissue transplantation
  • sexual transmission
  • vertical transmission
  • occupational transmission
  • saliva?
39
Q

How can we diagnose HCV

A
  1. Anti-HCV test (detects presence of antibodies, indicates exposure to HCV)
  2. HCV -RNA test (identifies presence of virus in blood, indicates active infection)
  3. Viral load/quantitative HCV test (measures the number of viral particles in peripheral blood)
  4. viral genotyping (determines type of HCV present)
40
Q

How does and acute infection with recovery compare to a acute infection which progresses to chronic serologically

A

acute with recovery
HCV RNA not present in recovery
‘ALT’ not present in recovery
Anti HCV present

acute with chronic
HCV RNA present
ALT present
Anti-HCV present

41
Q

incubation period of HCV

A

6-12 weeks

42
Q

Describe the clinical course of HCV

A

Incubation
6-12 weeks

Acute infection

  • Clinically mild, commonaly subclinical
  • Jaundice in 25% of patients

Chronic Hep C

  • high frequency: at least 60%
  • mostly preceded by clinically inapparent infection
  • slowly progressive over 20+ years
  • progression from mild hepatitis to cirrhosis
  • link to liver cancer
43
Q

What is the treatment of chronic Hep C

A

IFN alpha + ribavirin (+ boceprevir/ telaprevir for genotype 1)

also 2nd gen protease inhibitors (much better as stops production of new viral particles) e.g. sofosbuvir

44
Q

what recent advances have been made for hep C

A

might be able to potentially cure soon

45
Q

What other virus does the Hep B vaccine protect against?

Why?

A

Hep D
it’s an RNA defective virus, can only replicate when HepB is there too
Because relies on HepB producing it’s protein coat. It can be independently transmitted just cant cause an infection

46
Q

what is a ‘super infection’? why is it important

A

i think when you are infected by Hep B and Hep D?

huge reduction in recovery rate between a co-infection (90-95%) and a super infection (5-10%)

47
Q

which virus is Hep E quite like? what is the main difference?

A

Hep A

mortality with pregnancy

BDS2 BAMS lectures (9 decks)

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