Virology

Question 1

Which hepatitis has the highest risk of fulminant hepatitis in pregnancy?

Answer 1

Hepatitis E

Question 2

Hepatitis A summary

Answer 2

Faeco-oral
Asymptomatic in many children
Jaundice and transaminitis in adults more likely
Diagnose with serology
Effective vaccine available

Question 3

Hepatitis B summary

Answer 3

Diagnosis: HBcAb (evidence of previous infection), HBsAg (6 months = chronic), HBcIgM (acute infection), Anti-HBs (cleared infection)

Management: tenofovir or entecavir

Prevent mother to child transmission with antivirals, immunoglobulin and vaccination

Question 4

Hepatitis C summary

Answer 4

Chronic: Complications like cirrhosis, HCC, liver failure

Treatment: Direct acting antiviral (DAA)

Question 5

Hepatitis D

Answer 5

Can only occur as a co-infection with HBV, can have rapid progression to cirrhosis so need vaccination in hepatitis B

Question 6

Hepatitis E summary

Answer 6

Faeco-oral, undercooked pork
Liver failure rare except in pregnancy

Question 7

Yellow fever - definition

Answer 7

Flavirus transmitted by mosquitoes

Question 8

Yellow fever - geographical distribution

Answer 8

Africa and South America

Question 9

Yellow fever - cycle of transmission

Answer 9

1. Sylvatic cycle - transmits the virus between mosquitoes and non-human primates
2. Athropogenic - refers to effects or processes that are caused or influenced by humans e.g. urbanisation and deforestation, human migration, environmental changes due to human activities
3. Village epidemic - bridge between the sylvatic and urban cycles of yellow fever
4. Urban epidemic - human-to-human transmission of the virus via domestic mosquitoes

1-4 in Africa
1 and 4 only in S America

Question 10

Yellow fever - clinical features

Answer 10

Short incubation 3-6 days

Asymptomatic or mild febrile illness with some progressing to the toxic stages of infection

Toxic phase: characterised by antibody response, not so much viraemia.
Transaminitis and liver failure
Haemorrhage
Hypoglycaemia
Acidosis

Question 11

Risk factors for severe disease in yellow fever

Answer 11

• Older age
• Neutropenia
• AST >3500
• Hyperbilirubinaemia
• High RNA levels
• Renal dysfunction

Question 12

Yellow fever vaccine - notes on preparation

Answer 12

Live attenuated
Single dose likely provides life-long protections
Requires a cold chain

Question 13

Complications of the yellow fever vaccine

Answer 13

Yellow fever vaccine associated viscerotropic disease
Yellow Fever Vaccine-Associated Neurotropic Disease

Question 14

Contrainidcations to yellow fever vaccine

Answer 14

Older age or under the age of 6 months
Allergy to eggs
Previous thymectomy or MG
Primary of acquired immunodeficiency

Question 15

Galidesivir

Answer 15

Small molecule antiviral nucleoside analogue with some survival benefits shown in ebola, marburg, zika, yellow fever. Going into trials for YF

Has been used following YF vaccine administered in error in a patient post thymectomy