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Yr 3 - December lectures 2018 > Hepatitis A-E viruses > Flashcards

Hepatitis A-E viruses Flashcards

1
Q

What is the source of the hepatitis A, route of transmission, chronic infections? and prevent?

A

Faeces
faecal-oral
no chronic infection
prevented with pre/post exposure immunization

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2
Q

What is the source of the hepatitis B, route of transmission, chronic infections? and prevent?

A

blood / blood-derived body fluids
percutaneous permucosal
can cause chronic infection
prevented with pre/post exposure immunization

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3
Q

What is the source of the hepatitis C, route of transmission, chronic infections? and prevent?

A

blood/blood-derived body fluids
percutanoues permucosal
can cause chronic infection
prevented by blood donor screening, risk behavior modification

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4
Q

What is the source of the hepatitis D, route of transmission, chronic infections? and prevent?

A

blood/blood-derived body fluids
percutaneous/permucosal
can cause chronic infection
prevented by pre/post exposure immunization and risk behavior modification

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5
Q

What is the source of the hepatitis E, route of transmission, chronic infections? and prevent?

A

faces
faecal oral route
sometimes causes chronic infection
ensure sage drinking water

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6
Q

How is hepatitis A transmitted?

A

close personal contact (sex, household, child day care centers)
contaminated food, water (infected food handlers, raw shellfish)
blood exposure (rare)

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7
Q

What age groups is hep a highest?

A

late childhood/young adults

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8
Q

What are the clinical features of hepatitis A ?

A

incubation period: avg 30 days, range 15-50
jaundice by age group
- <6 = <10%
- 6-14 = 40-50%
- >14 70-80%
complications: fulminant hepatitis, cholestatic hepatitis, relapsing hepatitis

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9
Q

How is hep A diagnosed?

A

diagnosed by detection of HAV-IgM in serum by EIA

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10
Q

Which age group have the highest attack rates of hep A in and why?

A

5-14 year olds

- children serve as reservoir of infection

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11
Q

Which people are at greater risk of developing hep a?

A

travelers
homosexual men
injecting drug users

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12
Q

How can hepatitis A be prevented from spreading?

A

pre-exposure - vaccination
post-exposure (within 14 days)
- vaccinate household and other intimate contacts
- also vaccinate institutions such a child care centers and look at common sources of exposure (food)

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13
Q

How many serotypes and genotypes are there of hep E?

A

one serotype and 4 genotypes
1,2,4 = endemic areas
3= non-endemic areas

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14
Q

What are most hep E outbreaks associated with ?

A

facially contaminated drinking water

- most outbreaks in indian subcontinent, mexico, china, africa

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15
Q

What is thought to be a food source of infection with hep E?

A

swine meat uncooked or partially cooked

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16
Q

What are the clinical features of hepatitis E?

A

incubation period = avg 40 days, range 15-60
case-fatality rate = 1-3% but in pregnancy women 15-25%
illness severity = increased with age
chronic hepatitis occurs in immunocompromised patients

17
Q

What prevention and control measures should be undertaken by travelers to prevent getting hep E?

A

avoid drinking water (ice) of unknown purity, uncooked shellfish and uncooked fruit/veg not peeled or prepared by traveler
IG prepared from donors in western countries doe not prevent infection
recombinant vaccine in china
ribavirin is tx for chronic infections in immunocompromised

18
Q

How is hep B transmitted?

A

sex - sex workers and homosexuals are at particular risk
parenteral - iVDA, health workers at increased risk
perinatal - mothers who are HBeAg positive are much more likely to transmit to their offspring than those who are not - main mode of transmission in high prevalence populations

19
Q

Which body fluids is hep b most concentrated?

A

high in blood, serum and wound exudates
moderate in semen, vaginal fluid and saliva
low/not detectable in urine, faces, sweat, tears, breast milk

20
Q

What are the clinical features of hep b ?

A 
incubation period = avg 60-90 days, range 45-180
clinical illness (jaundice) 
- <5 = <10%
- 5 yrs = 30-50%
acute case facility rate = 0.5-1%
chronic infection 
<5 yrs = 30-90%
5 yrs = 2-10%
premature mortality = 15-25%
21
Q

What are the spectrum of conditions that can arise from hep B infection?

A

1) chronic persistent hepatitis = asymptomatic
2) chronic active hepatitis symptomatic exacerbations of hepatitis
3) cirrhosis of liver
4) hepaticellular carcinoma

22
Q

What % of cases of acute hep B resolve / become fulminant hepatitis?

A

90% resolution
1% fulminant hepatitis
9% HBsAg+ for >6 months

23
Q

What are the diagnostic markers of HBV?

A

HBsAg - if present for >6 months defines persistent infection
HBeAg - determines relative infectivity
Anti-HBe - seroconversion from HBeAg to anti-hie indicates progression towards resolution
Anti-HBc IgM - differentiates acute/recent infection from persistent infection or resolved HBV infection
Anti-HBc - always present in acute and persistent infection and in recovered infection
HBV DNA - marker of infectivity

24
Q

Why is HBV DNA useful?

A

diagnosis
assessing patients for treatment
assessing response to HBV antiviral therapy
assessing infected health workers for FTP

25
Q

What are the treatments available for hep b ?

A

interferon = for HbeAg +ve carriers with chronic active hepatitis - 30-40% response rate

Lamivudine = nucleoside analogue reverse transcriptase inhibitors, well tolerated, tendency to relapse on cessation of drug, resistance

adefovir, tenofovir and entecavir - nucleoside analogues for lamivudine resistant patients

26
Q

How can hep B be prevented?

A

vaccination

  • high effective recombinant
  • given to those at increased risk

hepatitis B immunoglobulin
- given to those already exposed to it - particularly efficacious within 48 hours of incident - can also be given to neonates at increased risk

other measures = screening for blood donors, blood and body fluid precautions

27
Q

What is the aim of hep b vaccine?

A

reach antibody levels of >100 miu/ml
80-90% of individuals mount a respond of anti-has level of >10miu/ml
standard schedule is 0, 1 and 6 months
booster in 5 years
poor responder anti-Hb 10-100miu/ml
no responder = <10miu/ml
poor responders given boost every 2 years

28
Q

How is hep D transmitted?

A

percutaneous exposures - injecting drugs

permucosal exposure= sex

29
Q

What are the clinical features of hep D?

A

co-infection

  • severe acute disease
  • low risk of chronic infection

superinfection

  • usually develop HDV infection
  • high risk of severe chronic liver disease
  • may present as acute hepatitis
30
Q

How can hep D be prevented?

A

pre or postexposure prophylaxis to prevent HBV infection

for superinfection - education to reduce risk behaviors among persons with chronic HBV infection

31
Q

What are the risk factors for hep c?

A

transfusion or transplant from infected donor
injecting drug use
hemodialysis
accidental injuries with needles/sharps
sex/household exposure to anti-HCV positive contact
multiple sex partners
birth to HCV infected mother

32
Q

How many particles are produced per day and how many genotypes of hep C are there?

A

10 trillion virus particles produced/day
6 genotypes
- 1,2 and 3 most common

33
Q

What are the clinical features of hepatitis C?

A

incubation period = avg 6-7 weeks, range 2-26 weeks
clinical illness (jaundice) - 30-40%
chronic hepatitis 70%
persistent infection - 85-100%
immunity = no protective antibody response identified

34
Q

What can HCV cause?

A

end stage cirrhosis
HCC case
liver transplants

35
Q

What factors accelerate clinical progression of HCV disease?

A

alcohol uptake
co-infection with HIV or HBV
male sex
older age

36
Q

What other manifestations can arise due to hep c infection?

A 
cryoglobulinaemia
- vasculitis = weakness, arthralgia, purpura
- glomerulonephritis
non-hodgkin lymphoma 
super infection with HAV
37
Q

How is hep C diagnosed in laboratory?

A

HCV antibody = generally used to diagnose infection - not useful in acute phase as it takes at least 4 weeks after infection before antibodies appear

HCV-RNA - use PCR- can be used in acute phase = mainly used in monitoring the response to anti-viral therapy

HCV antigen - an EIA for HCV antigen is available

38
Q

What are the treatments available for Hep C?

A

interferon = considered for patients with chronic active hepatitis - response rate 50% but many relapse after withdrawal

ribavirin - less experience - suggest combo with interferon is more effective

direct acting antivirals = boceprevir, telaprevir - in combo with other drugs

39
Q

How can hep c be prevented?

A

screening blood, organ and tissue donors

high risk behavior modification

blood and body fluid precautions

Yr 3 - December lectures 2018 (15 decks)

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