What Is Hepatitis D?

Hepatitis D virus is an infectious disease caused by hepatitis D virus (HDV) and hepatitis B virus such as hepatitis B virus. The disease has a worldwide distribution, especially in southern Italy, where it is highly endemic. The HBsAg carrier rate in developing countries is high, and there is a basis for HDV infection. China's investigation report indicates that there is an endemic epidemic. The HDV infection rate of HBsAg-positive people in various places is 0% to 32%. The HDV infection rate of severe hepatitis and chronic liver disease was significantly higher than that of asymptomatic HBsAg carriers. It is mainly transmitted through blood transfusions and blood products, similar to how hepatitis B is transmitted. HDV and HBV overlap infection can promote liver damage and easily develop into chronic active hepatitis, cirrhosis and severe hepatitis.

Basic Information

English name: viralhepatitistypeD; deltahepatitis
Visiting department: Department of Infectious Diseases, Hepatitis
Multiple groups: HBV infected

Common causes: Hepatitis D virus (HDV), Hepatitis B virus
Contagious: Have
way for spreading: Blood transfusion

Causes of hepatitis D virus

HDV is a defective single-stranded negative-strand RNA virus, which must rely on a hepatotropic DNA virus such as HBV to provide a shell for it to replicate. HDV is present in the nucleus and serum of hepatocytes in HBsAg-positive HDV infected individuals. Replicates mainly in hepatocytes. HDV is susceptible to mutation. Human infection with HDV can significantly inhibit the synthesis of HBV-DNA. The appearance of HDAg is consistent with the decrease of HBV-DNA in serum. With the turn of HDAg and anti-HD, HBV-DNA returns to its original level. It is mainly transmitted through blood transfusions and blood products, and is similar to the transmission of hepatitis B. HDV infection is mostly seen in HBV-infected people, and sporadic HDV infection can also be seen. HDV and HBV overlap infection can promote liver damage and easily develop into chronic active hepatitis, cirrhosis and severe hepatitis.

Clinical manifestations of hepatitis D virus

After human infection with HDV, its clinical manifestation is determined by the original HBV infection status. The incubation period is 4-20 weeks. There are two types:

1.HDV and HBV infection at the same time

Seen in the past without HDV infection, HDV and HBV infection at the same time, manifested as acute hepatitis D. Its clinical symptoms are similar to acute hepatitis B, and bilirubin and ALT elevations are seen twice during the course of the disease. HBsAg first appeared in the serum, then HDAg was positive in the liver. In patients with acute stage, HDAg-positive serum turned negative for several days, and then anti-HDIgM-positive. Anti-HDIgG was negative.

2. HDV and HBV overlap infection

The clinical manifestations are diverse, which may be acute hepatitis, chronic hepatitis, or severe hepatitis. More common in patients with chronic HBV infection, the symptoms are mainly determined by chronic HBsAg carriers before HDV infection, or HB chronic liver disease. If they are HBsAg carriers, they will appear to be acute HBsAg-positive hepatitis after HDV infection, but anti-HBVIgM negative, which is heavier than simple HBV infection. In the case of HBV chronic liver disease, due to the continuous infection of HBV and the continuous replication of HDV, the existing liver tissue lesions are aggravated, which can be manifested as acute onset of hepatitis or accelerated development of slow-lived liver and cirrhosis. Therefore, in the case of chronic hepatitis B, the original condition is stable, sudden symptoms worsen, and even liver failure occurs, which is similar to severe hepatitis, and the possibility of overlapping infection with HDV should be considered.

Hepatitis D virus examination

Serum test

Hepatitis D virus antigen (HDAg) and hepatitis D virus antibody (anti-HD) in serum.

2. Liver function test

Including bilirubin, thymol turbidity test, AST, ALT, A / G, prothrombin time, serum protein electrophoresis, etc.

3. Specific serum etiological examination

Including HBsAg, anti-HBs, HBeAg, anti-HBe, anti-HBc, anti-HBcIgM. Conditionally detect HBV-DNA, DNA-p, Pre-S1, Pre-S2, etc.

4. Serological testing

Some patients with HDV infection can be detected, and a considerable number of patients can only be diagnosed by detecting HDAg from liver tissue.

Diagnosis of hepatitis D virus

1. Hepatitis in HBsAg carriers in HDV endemic areas;

2. Bimodal serum ALT and bilirubin concentrations fluctuated in acute hepatitis B;

3. Hepatitis activity suddenly appears in inactive cases that have stabilized, or progressive deterioration in the course of chronic hepatitis B;

4. HBV replication indicators have been reduced or disappeared, and the clinical manifestations are worse in cases.

The diagnosis is determined by the detection of HDV serological markers. Serological diagnosis: HDV antigens and antibodies can be present in the serum at the same time. In screening, anti-HD detection is often the first step. Anti-HD detection includes radioimmunoassay (RIA) and enzyme adsorption (EIA).

Anti-HDIgM can appear in the acute early stage of clinical onset, which lasts 3 to 9 weeks and disappears during the recovery period; if it changes to a persistent infection state, it can continue to be positive, and is mainly 7S type. 19S type appeared. Therefore, it can be used as the identification of acute onset of concurrent infection and overlapping infection. In acute onset, after the anti-HDIgM titer began to decrease, the anti-HDIgG titer showed an increase, but it was also limited and disappeared within 2 to 18 months. The presence of persistently high titers of anti-HDIgG is a major serological marker of chronic persistent HDV infection.

Histological diagnosis: HDV (HDAg or HDVRNA) tissue staining in the nucleus of hepatocytes in liver biopsy specimens is the diagnostic method.

Hepatitis D virus treatment

There is no effective treatment for HDV infection, and the key lies in prevention. The main treatment is symptomatic treatment of liver protection. Antiviral drugs such as interferon mainly interfere with the synthesis of HBV-DNA and have no inhibitory effect on HDV-RNA synthesis.

Prevention of hepatitis D virus

1. Strict selection of blood donors to ensure the quality of blood and blood products is an effective method to reduce the incidence of hepatitis D after blood transfusion.

2. Extensive vaccination of HBV susceptible persons is a powerful measure to eventually eliminate the HBsAg carrier status, and it is also a practical method to control HDV infection.

3. Strictly implement the sterilization and isolation system, aseptic technique operation, implement one-time medical appliances for acupuncture and injection, or use one disinfection to prevent iatrogenic transmission.