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39 Cards in this Set

  • Front
  • Back
Where is Hep A most prevelent?
-high in s. america, africa, india and SE asia
-low in N. america, most western european countries
Who is at risk for hep A?
tourist, military personnel, missionaries, etc

Vaccination reccommended before travel
What is the serologic course of Hep A?
HAV replicates in the liver, excreted in bile and shed in stool
What is the incubation period of Hep A? And when is the peak activity before onset of elevated aminotransferases and jaundice?
28days is the incubation period

2wks before is the peak infectivity time
When is IgM detectable before onset of symptoms? How long can it persist? What role does IgG play in Hep A?
IgM is present usually 5-10days before onset of symptoms, but can persist up to 6months after

IgG appears in early detection and usually persist indefinitely.
How do you diagnose Hep A?
detection of IgM anti-HAV in serum
Who is at an increased risk for Hep A?
travelers to endemic areas
men having sex with men
injection drug users
no consensus for vaccination recommendations
How do many cases of Hep A occur and how do outbreaks look population wise?
many cases occur in community wide outbreaks where no risk factors can be identified.

but children seem to serve as a reservoir of infection and highest attack rates are 5-14yr olds
How is Hep A transmitted?
Who is at risk for Hep A through:

-close personal contact?
-fecal-oral contamination of food or water?
personal contact
-household or sexual contact
-daycare centers
fecal-oral contamination
-food handlers
-raw shellfish
-travel to endemic areas
-injection drug users
How do you prevent Hep A before exposure? after exposure?
preexposure: travelers to high HAV-prevalence regions:
1)0.02 ml/kg(protects 1-2mos)
2)0.06 ml/kg(protects 3-5mos)

1)within 2wks->0.02 is >85% effective
2)routine-household and other intimate contacts
3)selected situations:
common source exposure
What is Twinrix? What is the dosage? And who is it recommended for?
Bivalent HAV and HBV vaccine
1ml at 0,1,6 months
recommended for all susceptible persons>18yo
What type of antigen is Hep A?
blood borne Ag
What is the prevelence of Hep B?
350mil worldwide carriers
Chronic HBV is endemic in most parts of Africa, Asia and alaska (carrier rate>20%)

US prevalence=0.42%
What are the patterns of HBV infection?
high endemic areas: most infections are perinatally or during early childhood (>50% of people have evidence of chronic/past infections)

Low prevalence: most infections are young adults through high-risk sexual activity or IV drug use
If you acquire HBV as a child are you more likely or less likely to be a carrier?
more likely
What is the risk of chronic infection with HBV?
if you get it as a baby you are more likely to have chronic infection

Adults rarely have chronic infection
What is the disease burden of HBV?
-estimated 78000 new infections each year
-1.25mil US/350mil global with chronic infection
-5K US/500k Global die from chronic liver HBV each year
-4.9% US/30% global percent ever infected
Why is there a declining rate of HBV infection in the US?
HBV vaccine
What are the most predominant risk factors for HBV?
1. injection drug use
2. sexual exposure
What is the expected outcome of HBV infection in children?
acute HBV infection subclinical >90% of neonates and children
What is the expected outcome of HBV infection in adults?
70% have little/no symptoms
30% have icteric hepatitis
0.1-0.5% develop fulminant hepatitis
What is fulminant liver?
What is the chance of survival? Does it ever progress to chronic infection?
liver is necrosing
there is a 25% chance of survival

There is no progression to chronic infection
What is the overall risk of progression to cirrhosis with HBV?
-increase probability with longer chronic infection
-persistently detectable HBV DNA
-initial histology showing bridging necrosis
-older age
What are the clinical markers for HBV infection?
HBsAg infection
Anti-Hbc IgM
Anti-HBc IgG and HBsAg
Anti-HBc IgG and Anti Hbs
What do the clinical markers for HBV mean?
HBsAg infection
Anti-Hbc IgM
Anti-HBc IgG and HBsAg
Anti-HBc IgG and Anti Hbs
HBsAg infection: acute/chronic
Anti-Hbc IgM: acute infection
HBeAg: high infectivity
Anti-Hbe: low infectivity
Anti-HBs: immunity
Anti-HBc IgG and HBsAg: chronic infection
Anti-HBc IgG and Anti Hbs:resolved infection
What are some immune modulators for treating HBV?
therapeutic vaccines
What are some nucleotide analog for treating HBV?
adefovir dipivoxil
What two virus are associated with HBV?
What is the prevalence of HCV?
World: 170mil
AntiHCV+ = 3.9mil (1.8%)
HCV RNA+ = 2.7mil (1.4%)

world wide prevalence is highest in N. africa (egypt) and eastern mediterranean
What are the risk factors for Hep C?

long term hemodialysis
multiple sexual partners
mass injection and tradional practices
clotting factor tx prior to 1987(most people do have HCV)
blood transfusion or organ transplant prior to 1992
IV drug use (high prevalence)
birth from infected mother (bigger issue with HBV)
What is the current likelihood of transmission of HCV?
transfusion: 1/1mil
mom HIV- = 5%
mom HIV+ = 15-20%
hetero partner: 1/1000 per yr
needlestick injury:
HCV+ = 5%
HCV status unknown = 1%
Who develops chronic infection after HCV exposure?
most people
What is the outcome after HCV infection?
pts with spontaneous resolution have high HCV specific T-cell responses
Who has a greater chance of spontaneous recovery?
younger people
If you are an HCV carrier, what liver enzyme can be normal?
What percentage of people will develop cirrhosis from HCV infection? And what country has an higher frequency of HCV infections?
20% develop cirrhosis

What factors are associated with fibrosis?
duration of infection
alcohol >50gm/day
age > 40yo at infection
male gender
What do antibody test for HEP C indicate and are they good tests?
indicates past/present infection.

they are inexpensive, sensitive and specific, but have a low PPV in low prevalence populations and low sensitivity in immunosuppressed pts