Hepatitis D virus, PCR-quality
Why this test?
For differential diagnosis of hepatitis.
To detect viral hepatitis D and mixed hepatitis.
To monitor the effectiveness of treatment.
To make a prognosis of the course and outcome of the disease.
In what cases is it prescribed?
With the wave-like course of viral hepatitis B.
With rapidly progressive liver damage (fulminant hepatitis) and the disease exacerbation with viral hepatitis B patient.
With chronic liver diseases (chronic viral hepatitis B, cirrhosis).
When examining persons who have been in contact with infected people with delta hepatitis.
When monitoring treatment.
When monitoring the course of mixed hepatitis (probably simultaneous infection with viruses B, D and C).
The hepatitis D virus is a defective virus that contains a ring-shaped single-stranded RNA strand and is capable of replication only in the presence of the hepatitis B virus. HDV builds its envelope from the HBs-antigen and cannot fully reproduce without HBV. According to approximate estimates, about 5% of patients with viral hepatitis B are also infected with the hepatitis D virus.
There are 3 main genotypes of the virus, which differ in the severity of the course of the disease and are characteristic of certain geographical regions. The first genotype is the most common throughout the world, the second is found in East Asia, and the third - in South America. The virus is resistant to acidic environments and high temperatures, but is destroyed by alkali.
The source of infection is a patient with acute or chronic hepatitis D or a carrier of the virus. The main route of infection is parenteral, as with viral hepatitis B. Sexual and vertical (from mother to child) are rare, but probable ways of spreading the infection.
The risk group for infection with the virus includes injection drug users, recipients of donor organs and patients who are on hemodialysis or who receive frequent transfusions of blood components. The disease develops only with acute or chronic viral hepatitis B or HBsAg carrier, that is, with viral hepatitis D there is always a mixed infection. In case of co-infection (simultaneous infection with hepatitis B and D viruses), the disease is characterized by a shorter incubation period of 3-7 weeks. Hepatitis begins, as a rule, acutely, with an increase in body temperature, nausea, loss of appetite and jaundice.
Coinfection is accompanied by two periods of increased biochemical markers of liver damage (transaminases). The first is associated with the cytolytic action of the hepatitis B virus, the second - a few weeks later - is caused by the hepatitis D virus. For 90% of patients, co-infection ends with recovery. When infected with the hepatitis D virus in the presence of viral hepatitis B, a so-called superinfection occurs. Complete recovery is recorded in only 5-10%.
Distinguishing coinfection from superinfection is not always easy. Usually, they focus on the features of the course of the disease and the presence of anti-HBc class IgM in case of coinfection and antibodies class IgG in case of superinfection. Infection with viral hepatitis D reduces the likelihood of a successful response to antiviral therapy, and in 5% of cases, rapidly progressive liver damage even ends in death. Chronic hepatitis and cirrhosis, in turn, increase the risk of developing hepatocellular carcinoma, although a direct link between delta hepatitis and liver cancer has not been proven. As pronounced cirrhotic changes in the liver increase, the virus multiplies less and less actively.
Recipients of a donor liver infected with the hepatitis D virus have a latent form of infection. In the absence of viral hepatitis B or its suppression by immunoprophylactic methods, the multiplication of viral particles occurs only within the affected hepatocytes without spreading the infection to other parts of the liver. RNA of the virus is not detected in the blood.
The molecular genetic method of determining the genetic material of the virus in the blood is characterized by high specificity and sensitivity. The RNA of the virus can be detected in the blood by PCR a few days after infection, while antibodies to the hepatitis D virus appear only after a few weeks.
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