Delta agent is a type of virus called hepatitis D that causes symptoms only in people who have a hepatitis B infection.

Hepatitis D virus (HDV) is only found in people who carry the hepatitis B virus. HDV may make a hepatitis B infection or existing hepatitis B liver disease worse. It can cause symptoms in people with hepatitis B virus who never had symptoms.

Hepatitis D infects about 15 million people worldwide. It occurs in 5% of people with hepatitis B.

Risk factors include:

• Abusing intravenous (IV) drugs
• Being infected while pregnant (the mother can pass the virus to the baby)
• Carrying the hepatitis B virus
• Having had a hepatitis B infection in the past
• Men having intercourse with other men
• Receiving many blood transfusions

Hepatitis D may make the symptoms of hepatitis B more severe.

Symptoms may include:

• Abdominal pain
• Dark-colored urine
• Fatigue
• Jaundice
• Joint pain
• Loss of appetite
• Nausea
• Vomiting

• Anti-delta agent antibody
• Liver biopsy
• Liver enzymes

Many of the medicines used to treat hepatitis B are not helpful for treating hepatitis D. See hepatitis B.

Persons with long-term HDV infection may receive a medicine called alpha interferon for up to 12 months. A liver transplant for end-stage chronic hepatitis B may be effective.

Persons with an acute HDV infection usually get better over 2 to 3 weeks. Liver enzyme levels return to normal within 16 weeks.

About 10% of those who are infected may develop long-term (chronic) liver inflammation (hepatitis).

• Chronic active hepatitis
• Fulminant hepatitis

Call for an appointment with your health care provider if you have symptoms of hepatitis B.

Prompt recognition and treatment of hepatitis B infection can help prevent hepatitis D.

Avoid intravenous drug abuse. If you use IV drugs, avoid sharing needles.

A vaccine is available to prevent hepatitis B. It should be considered by people who are at high risk for hepatitis B infection.

Dienstag JL. Chronic viral hepatitis. In: Mandell GL, Bennett JE, Dolin R, eds. Principles and Practice of Infectious Diseases. 6th ed. Philadelphia, Pa: Elsevier Churchill Livingstone;2005:chap 112.