Transmission and symptoms
Transmission of the hepatitis D virus is mainly parental (via blood and body fluids), sexual or perinatal (at the birth of a child by an infected mother). The incubation period (time from the time of infection to the outbreak of the disease) is 3-7 weeks for HDV. The symptoms are similar to those of hepatitis A: in the so-called prodromal stage, which lasts 2-7 days, flu-like symptoms such as increased temperature and fatigue appear, as well as nausea, loss of appetite, pressure pain in the right upper abdomen and possibly diarrhea.
Other symptoms are acute skin rash and joint pain, although these do not always occur. In the second stage (duration 4-8 weeks) the virus settles in the liver. Adults now show jaundice (icterus).
In addition to the discoloration of the white dermis in the eye, and subsequently of the entire body surface, this liver manifestation manifests itself in a darkening of the urine with simultaneous decoloration of the stool. The liver is now clearly enlarged and painful. In about 10-20% of cases, an enlargement of the spleen and swelling of the lymph nodes can also be observed at this stage.
Diagnostics
Firstly, the hepatitis D virus can be transmitted simultaneously with the hepatitis B virus (simultaneous infection). On the other hand, a patient with existing hepatitis B can be infected with the HD virus (superinfection). Depending on which infection is present, different laboratory tests are possible.
In any case, a laboratory examination of the blood should be performed. The detection of hepatitis D-specific antigen is often better possible with a superinfection than with a simultaneous infection. Furthermore, the antigen is usually only detectable within the first to second week of the acute infection.
If the hepatitis D antigen is already negative, the antibody Anti-HDV IgM is detectable in the late acute infection stage. If a persistent (chronic) infection occurs, it can also persist (be permanently detectable). The IgM antibody is the antibody that acts more non-specifically against the virus and is the first to be formed during an infection.Anti-HDV IgG is another antibody that can be detected later.
IgG antibodies are more specific against the virus. It is detectable in the blood during a simultaneous infection after approx. 4-6 months after the onset of the disease.
In the case of a superinfection, the anti-HDV IgG antibody can be tested positive in the blood as early as 4 weeks after the onset of the disease. If testing for antigen or antibody is uncertain, but there is still a suspicion of hepatitis D infection, HDV RNA can be detected by PCR (polymerase chain reaction). RNA is the genetic material of the hepatitis D virus. In addition, the blood should be tested for antigens and antibodies of the hepatitis B virus.
