HEPATITIS D VIRUS

Structure & Property	Transmission	Pathogenesis	Clinical findings	Laboratory diagnosis	Treatment	
Family: deltavirus

Genome: single-strand RNA, -ve polarity.

Size: 35-37nm

Enveloped virion

Defective virus: 
- cannot replicate by itself.
- HBV is helper virus.
- can only replicates in cell infected with HBV.

Genome has no sequence homology to HBV.	Sexual contact

Blood, e.g. intravenous drug injections

Perinatally from mother to child.

Uncertain whether there is lifelong immunity.	Virus-infected hepatocytes are damaged by cytotoxic T cells. 	Hepatitis in patients with HDV and HBV are more severe than in those infected with HBV alone. 

Hepatitis in chronic carriers are more severe though incidence is the same. 	Diagnosis: detection of either delta antigen or IgM antibody to delta antigen in patient’s serum.	Alpha-interferon is used to relieve symptoms, does not eradicate carrier state.

A person immunized against HBV will not be infected by HDV.