Viral Hepatitis Flashcards
What is Hepatitis A?
The family Picornaviridae, genus hepatovirus
Single-stranded, positive sense RNA genome
Quasi-enveloped virions
How is Hepatitis A transmitted?
Faeco-oral versus blood-borne transmission
Incubation period of 15-50 days
What is the epidemiology of Hepatitis A?
Approx. 1.5 millions of cases worldwide annually
Developing countries with poor socio-economic conditions
300-500 cases annually in the UK
Mostly among age 15-34 and non-travellers
Outbreaks among MSM (2016/17) & IVDU (2001 & 2017)
What are the signs and symptoms of Hepatitis A?
Wide disease spectrum from asymptomatic to fulminant hepatitis.
Strong correlation with age: <10% symptomatic among children <6 years old versus 70% in adults.
Typical symptoms: Fever, malaise, anorexia/nausea, abdominal discomfort, diarrhoea, jaundice.
Extra-hepatic diseases.
Is Hepatitis A acute or chronic?
Acute presentation; 99% resolution
NOT an aetiology for chronic hepatitis
What is the timecourse of the immune response to Hepatitis A infection?
How is Hepatitis A diagnosed?
Based on serology:
- Acute infection: IgM reactive; unlikely if bilirubin level < 30umol/L
- Past infection: IgM non-reactive, IgG reactive
What are the public health implications of Hepatitis A?
Notifiable disease
Pre-exposure immunisation among population at risk
Post-exposure prophylaxis:
Within 14 days of exposure to index case: HAV vaccine +/- HNIG (for 60 years and above, chronic liver diseases inc CHB/CHC, immunocompromised contact)
Over 14 days: HAV vaccine +/- HNIG (for chronic liver diseases inc CHB/CHC, immunocompromised contact)
What is Hepatitis B?
The family Hepadnaviridae
Double-strained DNA with reverse transcriptase
Enveloped virions
10 genotypes (A-J) with distinctive geographic distribution
How is Hepatitis B transmitted?
Blood-borne transmission: horizontal & vertical
Incubation period of 40-160 days
What is the typical presentation of acute Hepatitis B?
Age related presentation & prognosis in acute hepatitis B.
Neonates & children: Mostly asymptomatic or anicteric; 90% HBV-infected neonates develop CHB, and 30% among children age <5 years.
Adult: 30-50% icteric hepatitis; 10% become CHB.
What are risks associated with acute Hepatitis B infection?
0.1-0.05% risk of fulminant hepatitis; related to co-infection with HCV/HDV.
Maternal HBeAg/Ab status & HBV viral load.
HBeAg as the most important risk predictor for vertical transmission.
What is the definition of chronic Hepatitis B infection?
Persistence of HBsAg for 6 months or more after acute HBV infection.
What are risks associated with chronic Hepatitis B infection?
Cirrhosis: 8-20% untreated CHB in 5 years;
Hepatocellular carcinoma: The annual risk of 2-5% among CHB cirrhotic patients; affected by host (e.g. alcohol abuse) and viral factors (e.g. high HBV viral load & qHBsAg).
What is the epidemiology of Hepatitis B?
Approximately 296 million people are living with CHB worldwide; CHB-related mortality at roughly 820,000 people per year.
What are the public health implications of Hepatitis B infection?
Acute hepatitis B: A notifiable disease
Pre-exposure prophylaxis:
- Routine childhood immunisation in the UK since 2017
- High risk population
Post-exposure prophylaxis:
- Neonate born to mother living with hepatitis B.
- Sexual partner: HBV vaccine +/- HBIG (within one week from the contact).
- Needle stick injury.
What is Hepatitis D?
Single-stranded, circular RNA genome.
A defective virus that relies on HBV for propagation.
How is Hepatitis D transmitted?
Blood-borne transmission
Incubation period: 3-6 weeks
What is the association between Hepatitis B and Hepatitis D?
HBV/HDV simultaneous co-infection: Similar to classic acute hepatitis B; mostly self-limited. <5% chronic infection.
HDV super-infection in CHB: 80% chronic infection. Increased risk of cirrhosis and HCC than CHB alone.
How is Hepatitis D diagnosed and treated?
Anti-HDV serology; other HDV investigations rarely used.
PEG-interferon alpha licensed for HDV superinfection in CHB.
Pre-exposure HBV immunisation.
WHat are the public health implications for Hepatitis D infection?
Notifiable disease
What is Hepatitis C?
The family Flaviviridae, genus Hepacivirus.
Single-stranded, positive sense RNA genome.
How is Hepatitis C transmitted?
Blood borne transmission.
Incubation period: 2-6 weeks.
What is the epidemiology of Hepatitis C?
58 million people living with chronic hepatitis C worldwide.
1.5 million new cases every year.
What is the presentation of Hepatitis C infection?
Acute infection:
- 30% spontaneous clearance
- 70% become chronic hepatitis C (CHC)
Hepatic versus extra-hepatic manifestation.
Cirrhosis (15-30% in 20 years) & HCC as complication of CHC.
How is Hepatitis C treated?
Revolutionised the treatment for acute/chronic HCV infection.
Any HCV cases should be considered:
- 8 or 12 weeks
- Sustained virological response (SVR) at week 12
- Pan-genotypic regimen
- Single-tablet regimen
- Drug-drug interaction
What are the public health implications of Hepatitis C infection?
Notifiable disease in the UK.
Nil vaccine available.
Nil post-prophylaxis available.
Active HCV screening.
Risk reduction (e.g. safe handling and disposal of sharps, protected sex).
What is Hepatitis E?
The family Hepeviridae, genus Orthohepevirus; species A strains (8 genotypoes) infect humans.
Single-stranded, positive sense RNA genome.
Quasi-enveloped HEV.
How is Hepatitis E transmitted?
Faeco-oral versus blood-borne transmission
Incubation period: 15-60 days
What are the natural reservoirs for the different strains of Hepatitis E?
G1 & G2: Obligate human pathogens
G3 & G4: Zoonotic; pigs & wild boar are natural hosts
What is the epidemiology of Hepatitis E?
Approximately 20 million new HEV cases worldwide annually
3.3m symptomatic hepatitis E
44,000 mortality annually
UK is a HEV G3 endemic country
What is the clinical manifestation of Hepatitis E?
Mostly self-limited; advised against alcohol during the course
Hepatic and systemic symptoms
Which groups are particularly at risk of developing Hepatitis E infection?
Pregnant women: G1; fulminant hepatic failure and obstetric complications (e.g. eclampsia and haemorrhage); 25% maternal mortality & high perinatal infant mortality.
Chronic liver disease patients.
Immunocompromised patients: May develop chronic hepatitis E (G3 & G4)/
How is Hepatitis E diagnosed?
Immunocompetent: HEV serology
Immunocompromised: HEV PCR
What are the public health implications of Hepatitis E infection?
Notifiable disease
HEV patient should avoid prepping food during the first 2 weeks.
Immunocompromised and chronic liver disease patients should avoid consumption of undercooked meat (pork, wild boar and venison) and shellfish.
HEV vaccination: Only licensed in China.
What is the treatment of Hepatitis E?
Only indicated in chronic hepatitis E as most acute HEV infection are self-limited.
