Hepatitis Viruses Flashcards
What is the only DNA hepatitis virus?
HBV (B for Both)
Which hepatitis viruses are fecal-oral transmission?
A and E.
Which can cause acute viral hepatitis?
All of them.
Which can cause chronic disease?
B,C,D. (The ones transmitted by blood).
What family of virus is HAV in?
RNA picornavirus.
What are the structural characteristics of HAV/picorna?
naked. icosahedral. +ssRNA.
How long is the incubation period in HAV before pt develops acute viral hepatitis (if they do)?
Short, weeks (15-40 days). Often asymptomatic.
What does +HAV IgM indicate?
Acute hepatits A infection.
What does +HAV IgG indicate?
IgG antibody indicates prior HAV infection and/or prior vaccination. Protects against reinfection.
Who should be vaccinated?
Travelers to endemic areas. Starting in 2005, part of routine peds vaccinations.
What kind of virus is HBV?
DNA hepadnavirus. DNA = circular!
How is HBV transmitted?
Parenteral, sexual, perinatal.
What is the HBV virus called with it is intact?
Dane particle. Big ol’ Bad HBV. dsDNA w/ DNA polymerase surrounded by icosahedral capsid with antigenic protein spikes sticking out, all surrounded by an envelope.
What exactly is HBsAg?
Filamentous structures composed of the envelope and some capsid proteins that have broken off from the virion.
Forms spheres and tubules 22nm in diameter.
Not infective.
Why do we care about HBsAg?
Antibodies against HBsAg are protective.
What exactly is HBcAg?
It is the core of the virion, the capsid w/out the protein spikes. Antibodies against this are NOT protective.
What exactly is HBeAg?
A soluble component of the core that is released during active infection and viral growth. Indicates highly infectious state.
What is the job of the polymerase of HBV?
1) DNA polymerase will complete the partial dsDNA of the virus
2) Host RNA polymerase makes mRNA out of this, host machinery makes proteins
3) Viral DNA polymerase then REVERSE TRANSCRIBES viral RNA to DNA for genome of progeny