Hepatitis Viruses Flashcards
What Hepatitis viruses are blood borne?
Hep B, Hep C and Hep D
What type of genome is Hep A?
single stranded RNA genome
How is Hep A transmitted?
faecal - oral route
person - person
water borne
Food borne
What are the clinical features of Hep A?
Incubation period of 2 - 7 weeks.
No chronic disease
Low mortality
How do you diagnose Hep A?
Anti-HAV antibodies in the blood
IgG in the blood
HAV antigens in faeces
What type of genome is Hep B?
Partially double stranded DNA genome
What are the characteristics of Hep B?
Hepadnavirus - virus affects the liver
Very infectious - especially if the individual is E antigen positive.
Common in the younger generation
What type of particles are present in Hep B? - describe them.
Dane particles - spherical
DNA genome in the centre.
Viral casting of excessive surface antigens
How is Hep B transmitted?
Blood borne - IV drug use
Perinatal - infected mother transmits the disease to their baby when blood mixes during childbirth.
Sexual transmission - homo and hetro
Define a carrier.
An individual who tests positive for surface antigens for longer than 6 months but hasn’t developed antibodies against the virus.
How can individuals be immunised against Hep B?
Passive immunisation - Antibodies against Hep B are given to the individual at high risk.
Active immunisation - Hep B surface antigen absorbed on to a aluminium hydroxide adjuvant is given intramuscularly.
When is passive immunisation used?
Used In an non-immune individual with a single acute exposure.
When must the passive immunisation be used after exposure to hep B?
Within 48 hours
How many dosages are required in active hep B immunisation? When must each dose be administered?
3 dosages
Initial dose - a dose 1 month later - a dose 6 months later
When must an individual be tested for response to the active vaccination against Hep B?
2 - 4 months after the last dosage of the vaccination.
What are non-responders to the active Hep B vaccination given?
HBIG (if working in the occupational setting)
Suppressing the viral load via;
Nucleoside analogues
Nucleotide analogues
Immunomodulatory agents
What is indicated if the Hep B antibodies are found in someones blood?
That the individual has been vaccinated.
That the individual has had the virus before.
What is indicated if the Hep B E antigens are found in someones blood?
That the individual still has an active and persistent form of Hep B and is at great risk of chronic liver disease.
How many genotypes of Hep C are there?
6
Is there a vaccine for Hep C?
No - too many genotypes and the surface antigens are constantly evolving.
What kind of genotype is Hep C?
Enveloped RNA virus
What are the clinical feature of Hep C? (How does hep C present?)
Both acute and Chronic is Subclinical
25% present with jaundice in acute Hep C.
How is Hep C transmitted?
Blood borne:
Iv drug
Transplantation
Vertical transfer - mother to child
Sexually transmitted
What tools are used to diagnose Hep C?
Anti-HCV test - detects antibodies to determines if the patient has been exposed to hep C
Viral genotyping - determines which genotype of Hep C.
Viral load test - determines how many viral particles are in the blood
HCV RNA - determines if the virus is active
What are the outcomes of Hep C?
Treated at the acute stage = resolution
Stable chronic disease
or;
Chronic disease can progress to; Cirrhosis Hepatocellular cancer Liver disease Death
What is the treatment for Hep C?
Interferon alpha combined with:
Ribavirin
telprevir - treatment of genotype 1
Second generation protease inhibitors:
Sofosbuvir
What does Hep B commonly co-infect with?
Hep D (Hep D requires B for replication)
How is Hep D transmitted?
Blood borne
Parental
Sexually transmitted
Alongside Hep B
How do you vaccinate against Hep D?
Hep B vaccinations prevents Hep D.
What are the outcomes of Hep D?
Co-infection with Hep B = commonly resolution.
Super-infection = commonly chronicity, which leads to cirrhosis and hepatocellular cancer.
How is Hep E transmitted?
Faecally contaminated water.
What is the outcome of Hep E?
No chronic disease
How long is the incubation period for Hep A?
2 - 7 weeks
