Lecture 5 (up to slide 20)

Question 1

Hepatitis Virus

Answer 1

Diverse viruses cause hepatitis
All have specific tropism for liver
Replicate in hepatocytes

Question 2

5 viruses responsible for human disease

Answer 2

Hepatitis A (HAV) – picornavirus (RNA+)
Hepatitis B (HBV) – hepadnavirus (dsDNA)
Hepatitis C (HCV) – flavivirus (RNA+)
Hepatitis D (HDV) – delta virus (RNA-)
Hepatitis E (HEV) – calicivirus-like (RNA+)

Question 3

HEPATITIS A VIRUS (HAV): PROPERTIES

Answer 3

Major cause of infectious hepatitis
ssRNA(+) Picornavirus, no envelope
Spread through ingestion of contaminated food, shellfish, water
Reaches liver via hepatic portal system
Slowly replicates in hepatocytes (not cytopathic)
Shed into bile to small intestine via bile duct
Shed in stool 10 days before symptoms
Clearance of virus by
NK cells, CD8+ cells, antibodies
Symptoms – fever, anorexia, nausea, jaundice
No chronic infection, not oncogenic

Question 4

HEPATITIS B VIRUS (HBV): PROPERTIES

Answer 4

Enveloped virion; Hepadnavirus
3 forms of HBsAg (hepatitis B surface antigen)
HBeAg (hepatitis Be antigen)
Partial dsDNA virus (incomplete genome)
Dane particle with antigenic decoy particles (HBsAg)
Icosahedral capsid formed by HBcAg (hepatitis B core antigen)
Contains a reverse transcriptase (replicates through RNA intermediate) & a protein kinase
Transmitted in blood semen, saliva, breast milk, menstrual & vaginal secretions & amniotic fluid
Acute or chronic infections
Symptomatic or asymptomatic disease
Slowly replicates in hepatocytes (minimal cytopathic damage)

Question 5

what are the 4 stages of acute disease

Answer 5

incubation period
preicetric
icteric
convalescent period