viral hepatitis

Question 1

what percent of HBV and HCV infections progress to chronic infection?

Answer 1

HBV: 5%
HCV: 80%

Question 2

describe the infectivity of HAV

Answer 2

peak infectivity during 2 weeks prior to onset of jaundice, elevated liver enzymes

Question 3

who does HAV usually infect? who does HAV cause acute hepatitis in?

Answer 3

most commonly infects in early childhood

acute hepatitis seen more in adults

Question 4

how is HAV diagnosed?

Answer 4

IgM anti-HAV for acute infection

IgG anti-HAV for past infection

Question 5

how can HAV and HBV be prevented

Answer 5

passive immunization with gamma globulin

• HBsAb for HBV
  vaccine: alone for children, Twinrix with HBV for adults

Question 6

why is HAV a candidate for eradication

Answer 6

effective vaccine
only one serotype
humans are only reservoir

Question 7

describe the rates of chronicity of HBV in different age groups

Answer 7

90% if younger than 1
30% if 1-5
2% older than 5

Question 8

why does HBV continue to be so prevalent in endemic areas?

Answer 8

infection at young age b/c of high prevalence leads to high rates of chronic infection->lots of carriers

Question 9

what is the genome of HBV?

Answer 9

partially dsDNA (circular when complete)

Question 10

what two things contribute to HBV chronic infection?

Answer 10

genome maintained extrachromosomally

particles and filaments hide virions

Question 11

how is HCV diagnosed?

Answer 11

ELISA for anti-HCV with no distinguishing b/w IgG and IgM

confirm with PCR assay for HCV RNA

Question 12

what is the genome for HDV?

Answer 12

circular -ssRNA

Question 13

how is HDV diagnosed?

Answer 13

anti-HDV or HDV RNA or delta antigen