Hepatitis D

Organism

Hepatitis D or delta hepatitis is a virus causing liver inflammation in patients who are already infected with hepatitis B virus. The delta virus is unable to infect cells by itself and requires the presence of hepatitis B in order to multiply. It is associated with severe liver inflammation in patients with hepatitis B; the liver inflammation tends to be more severe in patients who acquire delta virus after infection with hepatitis B, compared to patients who acquire both viruses at the same time.

Mode of Transmission

Hepatitis D is transmitted in a similar way to hepatitis B, that is via contact with blood or body fluids, particularly on shared needles, and through sex.

Regions Affected

Hepatitis D is found world-wide, although its prevalence varies widely. It is common in hepatitis B infected individuals in southern Italy and the Mediterranean, North Africa and South America. The prevalence of hepatitis D virus is low in the United Kingdom except for in particular risk groups, such as intravenous drug users, haemophiliacs and male homosexuals.

Prevention

As hepatitis D virus cannot exist without hepatitis B infection, infection can be prevented by taking measures to avoid hepatitis B infection. If a patient is hepatitis B positive, they must avoid further exposure to blood products and body fluids, for example by avoiding needle sharing and unprotected sex.

Immunisation

None available.

Symptoms and Signs

Hepatitis D can cause acute or chronic exacerbations of liver inflammation due to hepatitis B, depending on the timing of infection with the 2 viruses. If an individual acquires both viruses together, they may develop a severe acute hepatitis with jaundice and higher mortality than with acute hepatitis B infection alone. When an individual with chronic hepatitis B infection acquires hepatitis D virus, this can result in an acute exacerbation of liver inflammation, or chronic hepatitis D infection with more rapid progression to cirrhosis and liver cancer.

Tests

Infection with hepatitis D virus is diagnosed by detecting antibodies to the virus in the blood stream. The virus itself can be detected in blood samples during acute infection.

Treatment

There is no specific treatment for delta hepatitis. Treatment of acute infection is supportive. Interferon alpha is used to treat patients with chronic hepatitis B and hepatitis D infection. Some studies have suggested that a dose higher than that usually used for hepatitis B infection may be beneficial.

Complications and Outcome

Acute infection with both hepatitis B and hepatitis D viruses causes severe liver inflammation and has a higher risk of mortality compared to acute hepatitis B infection alone (5% compared to 1%). However if the patient recovers, they usually clear both viruses completely. In patients with chronic hepatitis B infection who acquire hepatitis D virus, again they may develop acute liver inflammation. Hepatitis D infection in this setting is more likely to become chronic, with more rapid progression of liver inflammation and damage, leading to cirrhosis.

By Dr Ann Chapman