Synonyms: HDV
Clinical significance
HDV, also called the delta virus, is a single-stranded RNA virus that uses the envelope of the hepatitis B virus (HBsAg). It is considered a “defective virus” because it must be associated with the hepatitis B virus (HBV) to cause infection.
Transmission and risk factors are similar to those of HBV: drug use (especially injected drugs), and living with or having sexual intercourse with chronic HBsAg carriers. HDV is endemic in the Mediterranean, South America, southern Africa and the Middle East. In Italy, the reduced endemicity of the delta virus is clearly due to the smaller pool of chronic HBsAg carriers in the general Italian population in recent years, which reduces the chance of the delta virus meeting HBsAg-positive people.
Acute HDV infection can occur as a co-infection, when HDV is transmitted at the same time as acute HBV infection, or as a superinfection, when a patient who is already a chronic HBV carrier later also becomes infected with HDV.
Clinical indications
To help diagnose delta virus co-infection or superinfection in HBsAg-positive people.
Sample type
The patient must have a blood sample taken.
Preparation
You must fast for at least 8 hours; a small amount of water is allowed.
Notes
The absence of anti-HDV antibodies indicates no exposure to HDV.
The presence of anti-HDV antibodies indicates exposure to HDV.
A negative test result does not rule out the possibility of exposure to or infection with HDV. Anti-HDV antibodies may not be detectable until 2-8 weeks after infection.