Hepatitis A-E viruses Flashcards Preview

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

Flashcards in Hepatitis A-E viruses Deck (39)
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1

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

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

2

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

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

3

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

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

4

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

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

5

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

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

6

How is hepatitis A transmitted?

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

7

What age groups is hep a highest?

late childhood/young adults

8

What are the clinical features of hepatitis 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

9

How is hep A diagnosed?

diagnosed by detection of HAV-IgM in serum by EIA

10

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

5-14 year olds
- children serve as reservoir of infection

11

Which people are at greater risk of developing hep a?

travelers
homosexual men
injecting drug users

12

How can hepatitis A be prevented from spreading?

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)

13

How many serotypes and genotypes are there of hep E?

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

14

What are most hep E outbreaks associated with ?

facially contaminated drinking water
- most outbreaks in indian subcontinent, mexico, china, africa

15

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

swine meat uncooked or partially cooked

16

What are the clinical features of hepatitis E?

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

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

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

How is hep B transmitted?

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

Which body fluids is hep b most concentrated?

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

What are the clinical features of hep b ?

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

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

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

22

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

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

23

What are the diagnostic markers of HBV?

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

Why is HBV DNA useful?

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

25

What are the treatments available for hep b ?

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

How can hep B be prevented?

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

What is the aim of hep b vaccine?

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

How is hep D transmitted?

percutaneous exposures - injecting drugs
permucosal exposure= sex

29

What are the clinical features of hep D?

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

How can hep D be prevented?

pre or postexposure prophylaxis to prevent HBV infection

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