For hepatitis D (also known as the hepatitis delta virus) to develop, a person must first be infected with hepatitis B. Both viruses are transmitted through infected blood. The hepatitis B virus, or more precisely the envelope of the virus, must be present in order for hepatitis D viruses to replicate. Without already being infected with the hepatitis B virus (HBV), no infection with the hepatitis D virus is possible. In the event of such a co-infection, the course of HBV is normally more severe, making complications and advanced cirrhosis more likely. The co-infection is particularly dangerous when a patient initially has a chronic HBV infection and is later infected with the delta virus, because the liver often sustains damage more quickly under these conditions (a superinfection) than during simultaneous infection with both viruses. This makes hepatitis D the most dangerous form of hepatitis. It is relatively rare in Switzerland.
Mild flu-like symptoms such as fever, pale stools, dark urine or yellow-coloured skin and whites of the eyes can arise. Chronic fatigue is a common symptom among those infected with HDV. Symptoms are rare or do not appear at all during the acute phase of the infection. Even with chronic infections, symptoms do not always occur until cirrhosis or liver cancer develop.
The symptoms of HBV and HDV infection are very similar.
As hepatitis D only occurs in combination with hepatitis B, a test for HDV only makes sense when hepatitis B has already been diagnosed (HBsAg positive). Without the envelope of the HBV virus, the HDV virus is unable to replicate.
If HBsAg antigens are present and a HDV infection is suspected, the affected person will be tested for anti-HDV antibodies. In the event of a positive result, further tests will be carried out to check whether the virus has already been cured or if it is active. This necessitates a PCR test which examines the HDV-RNA. This test can only be carried out in specialist labs.
PEG interferon therapy is effective not only against HDV but also against HBV by inhibiting the replication of both virus types. Other medications, such as nucleoside and nucleotide analogues (lamivudine, entecavir, tenofovir) are suitable as treatments for HBV but they appear to have no effect on the delta virus.
Once treatment can be ceased, regular monitoring by a doctor remains important. The hepatitis D viral load can suddenly begin to climb even after years have passed.
Infection and prevention
Infection with the delta virus occurs via contact with blood or other bodily fluids, like the hepatitis B virus. People with numerous sexual partners, an occupation in healthcare, with tattoos and piercings or those who share needles are at the highest risk. Transmission from mother to newborn is also possible.
Vaccination against HBV also prevents infection with HDV and is one of the best preventative measures. Wearing gloves when handling foreign blood and disinfection (with sterilising agents) are essential to minimise the risk of infection.
Safer sex is advised as is avoiding sharing personal care items such as toothbrushes and razor blades.