HAV Flashcards
HAV is what kind of virus?
Picornaviridae…enterovirus (like coxsackie or polio)
What kind of genome does HAV have?
+ssRNA with a VPg protein cap and a polyA tail
What kind of proteins are encoded for in the HAV genome?
Structural and non-structural
What is the outermost layer of the HAV virus?
Protein shell…NOT an envelope
What is a benefit of having a protein shell INSTEAD of an envelope?
Protein shell is more stable and can withstand harsher conditions…like the stomach
Why is it important that the HAV can survive past the stomach?
HAV originally infects mucosal epithelial cells
What happens after HAV infects mucosal epithelial cells?
HAV replicates and releases into the bloodstream
What cells have the HAV cell receptor 1 glycoprotein (HAVR-1) necessary for HAV infection?
Liver and T cells
Does viral entry/replication directly harm liver cells?
HAV is NOT cytolytic…just causes the cells to display MHC class I
Since HAV is not cytolytic, what damages the liver cells?
Cytotoxic T cells kill the liver cells…after the virus is already pooped out
How long before becoming jaundice is the virus excreted?
Roughly 10 days
Since HAV enters circulation in the intestine, what kind of transmission is it? What are risk factors?
HAV is fecally-orally transmitted (contagious 10-14 days BEFORE symptoms)
Contaminated seafood or imported berries
Summer camps, schools, etc.
What are some methods of inactivation of HAV?
Chlorine treatment of drinking water
Formalin treatment
UV radiation
Does HAV have a short or long incubation period?
Short…2-8 weeks
When does an HAV typically present? How long do the symptoms usually last?
HAV usually presents 15-50 days post exposure
HAV infection intensifies for 4-6 days
What are the symptoms of an HAV infection
Often asymptomatic (90% of kids; 25-50% of adults)
Fever Fatigue Nausea Anorexia Abdominal pain Dark urine Jaundice (70-80% of adults...10% of kids)
What percentage of people with HAV infection do NOT recover and develop a fulminant infection? What percentage of those who develop the fulminant infection die of the infection?
1%
80% of that 1% die due to the infection
How is HAV diagnosed?
ELISA (anti-HAV IgM)
IgG indicates a prior infection
How is HAV treated? What prophylactic treatment is available?
HAV infection is treated supportively
Pooled immune globulins can be given to contacts of people who are infected
What kind of vaccine is available for HAV?
Killed HAV infection
Given to children and adults at high risk of infection; travelers to endemic regions
Administered to children at 2yo and adults in conjuncture with HBV vaccie
What percentage of all acute hepatitis cases are caused by HAV?
40% of acute hepatitis cases are HAV
