Hepatitis D

blood-borne pathogen that causes fulminant hepatitis and liver cancer. It has the same symptoms as Hep B, but it causes worse problems. 

It is not really a full virus--more like a viroid or satellite virus--it can't even replicate on its own and requires Hep B. It may have evolved from a primitive viroid-like RNA

it infects the cell, gets in, replicates DNA in the nucleus via a symmetric rolling circle mechanism.

It replicates in the liver and causes fulminant hepatitis, using Hep B envelope protein (S antigen) to package its RNA genome

two forms of hepatitis delta antigen

• small delta antigen is needed for replication
• large delta antigen is part of the virion

• cellular RNA polymerase I is used to produce the antigenome
• Genome replication may use cellular RNA pol II

• One open reading frame, complementary to genome RNA
• - a polyadenylated mRNA is synthesized by cellular RNA polymerase

There are self-cleaving motifs used on both genome andcomplementary antigenome RNAs

can be folded into a rod-like structure through extensive internal base pairing

1) it is really important clinically

• By itself: nothing
• Infected with both B and D at the same time
• Infected with Hep B, cleared and later exposed to HDV: bad

not that terrible; you're still at the 90%: 10% level where 90% are cleared; 10% get fulminant hepatitis

You don't really go chronic. You can either recover or go straight to the really bad stuff

This is when you go from an asymptomatic to a chronic disease

This is a super infection