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Hepatitis D (HDV) (General (Similar to a plant viroid (Small piece of RNA…
Hepatitis D (HDV)
General
Can only replicate in the presence of HBV
Exacerbates HBV pathology
Defined originally by the delta antigen
Similar to a plant viroid
Small piece of RNA encoding delta antigen
Uses the HBV surface protein in it's envelope
For attatchment
Transmission
Like HBV
Injecting drug use
Percutaneous
Sexual contact
Permucosal exposure
Epidemiology
~15millHBV+, HDV+
Infection
Parts of South America
Asia
Parts of Africa
Only found in places where chronic HBV infection is present
Chronic HBV Infection
Northern South America
Africa
SE Asia
Clinical Features
Pathology
Similar to other viruses
Though more severe
Greater risk of fulminant disease
Coinfection
Severe acute disease
Low risk of chronic infection
Superinfection
Severe acute disease
Usually chronic
Severe chronic liver disease
Serological Time Course
Typical Coinfection
Viremia
Just before onset of symptoms
Coincides with symptoms and ALT
Anti-HBs
Response sufficient for clearance
Persists
IgM
Peaks with symptoms
Superinfection
Symptoms
Coincide with initial ALT peak
Jaundice
Only initial
ALT
Initial peak
Then fluctuates at a low level
IgM
Not sufficient to clear infection
Anti-HBs
None
HBsAg Persists
Viremia
Persists
Control
Vaccine
HBV
HBsAg produced in yeast
95% efficiency
Long lived
Given to newly born infants
Coverage is increasing
Global 82%
Not in the UK
Infection rates low
Therapy
Interferon alpha
Reverse-Transcriptase Inhibitors
Chronic disease
Reduce viral load
Not curative and only partially effective
Can get RT resistance
New
Entecavir
Tenofovir