Viral Heptatitis Flashcards
What are the viruses that cause viral hepatitis?
hep A hep B hep C hep D hep E
hep G
yellow fever
EBV and VZV can cause hepatitis during the course of their invections
What set of three viruses make up 90% of all viral hepatitis?
hep A, B and C
Which ones can form chronic infection as well as acute?
B C and D
A and E (the ends and the vowels) only do acute
What is another name for the hepatitic virus?
GB virus C
Hep G is in the same family as what other hepatitic-causing viruses?
HCV and YFV (Flavoviridae)
What are the morphological characteristics of hepatitis G?
RNA virus, ss+ nonsegmented
icosahedral
enveloped
How is hep G transmitted?
exposure to contaminated blood products in humans
Individuals with Hep G are likely to be coinfected with what?
hep B and Hep C or both
What kind of infection does Hep G cause?
hard to say - initially through to be associated with chronic hepatitis and hepatocelluar carcinoma
not probably not hepatocellualr carcinoma and maybe not even hepatitis at all - might infect lymphocytes (maybe important for HIV course)
it’s probably the coinfection with B and C that cause the hepatocellular damage
What is the viral family for HAV?
Picornaviridae
What is the viral family for HBV?
hepadnaviridae
What is the viral family for HCV?
flaviviridae
What is the viral family for Hep D?
deltavirus
What is the viral family for HEV?
caliciviridae
CalicEEE
Which three hepatitis viruses have ssRNA + DNA (group IV)?
HAV
HCV
HEV
also HGV I think
Which hep virus has partially double stranded DNA (group 7)?
HBV
Which hep virus has a negative sense ssRNA genome (group 5)?
hepatitis D
Which two hepatitis viruses are not enveloped?
HAV and HEV are non-enveloped
B, C, and D are enveloped
this makes sense for transmission
HAV has a protein that is covalently attached to the 5+ end of the genome. Wat is it?
the VPg protein
also has a polyA tail
Describe the extent of HAV’s capsid resistance
stable at ph 1
resistant to many solvents, detergents and desiccation
What substances can inactivate HAV?
chlorine treatment of drinking water
formalin treatment
UV radiation
What’s the route of infection for HAV?
fecal oral
What cells are first infected by HAV?
cells expressing the HAV receptor 1 glycoprotein (HAVCR-1) - liver and T cells
How soon before the onset of jaundice does the virus start shedding in stool
10 days
true or false: HAV is cytotoxic to hepatocytes, causing hepatitis.
false - it’s the immune response to virally infected hepatocytes mediated by cytotoxic T cells that cause disease
What percentage of worldwide acute heptaitis cases are caused by HAV?
40%
True or false: 90% of children and 25-50% of infected adults will have asymptomatic, non-productive infections.
false - asymptomatic, but productive
What are the symptoms of an acute HAV infection?
4-6 days with fever, fatigue, nausea, loss of appetitie, abdominal pain, dark urine, jaundice
HAV infections resolve 99% of the time…except….
1 percent will have fulminant infection which is associated with an 80% mortality rate
How do you determine acute HAV infection with serology?
ELISA positive for anit-HAV IgM
WHat are the treatment options for HAV?
mostly just supportive for the actual patient
- prophylaxis with immune globulin serum given to contacts of an HAV infected individual
- killed HAV (formalin) vaccine given to children and adults at high risk for infection
HAV and HEV are clinically very similar. WHat are some differences?
HEV has a slightly longer incubation period but disease is slightly more severe with an overall mortality of 1-2%
HEV infection is particularly dangerous for what population?
pregnant women - mortality rate of 20%
Why might HEV be worse in pregnant women?
immunological and hormonal factors probably:
maternal immune system is altered in that T cells are reduced up to the 20th week of gestation which may lead to an increased susceptibiltiy to viral infections
levels of HCG are up and have a suppressive effect on cell-mediated immunity
ultimately, the hepatitis virus doesn’t have much cytotoxic effect but it can have some. If you let it go uncontrolled you can get more damage to the synovial cells that line the liver. When you damage those cells you expose the underlying hepatoytes. it’s speculated that endotoxins from the gut will gain more access to the hepatitis which is EXTREMELY toxic to hepatocytes