Hepatitis D

Notification requirement for hepatitis D

Hepatitis D infection is a ‘routine’ notifiable condition and must be notified by medical practitioners and pathology services in writing within 5 days of diagnosis.

This is a Victorian statutory requirement.

Primary school and children’s services centre exclusion for hepatitis D

Exclusion is not applicable.

Infectious agent of hepatitis D

Hepatitis D virus (HDV) is a virus-like particle consisting of a coat of hepatitis B virus (HBV) surface antigen and a unique internal antigen, the delta antigen.

HDV is unique in that it can only replicate in the presence of HBV. Therefore, it only occurs among people who have HBV infection.

Identification of hepatitis D

Clinical features

Onset of disease is usually abrupt, with signs and symptoms resembling those of HBV infection.

HDV infection may be severe.

HDV infection may occur as an acute co-infection (simultaneously) with HBV infection or as a superinfection in people with chronic HBV infection.

Acute HDV co-infection is usually self-limiting, whereas HDV superinfection usually progresses to chronic hepatitis. Fulminant cases occur in superinfections rather than in co-infections.

Children can have a severe clinical course, which usually progresses to severe chronic hepatitis.

Diagnosis

Serological diagnosis is made by:

• detection of total antibody to HDV (anti-HDV) by enzyme-linked immunosorbent assay (ELISA); a positive HDV IgM result indicates ongoing replication
• detection of HDV antigen in serum, which is present earlier than anti-HDV
• detection of HDV-specific RNA by polymerase chain reaction (PCR) testing; PCR is the most sensitive assay for assessing HDV viraemia.

Incubation period of hepatitis D virus

The incubation period is approximately 2–8 weeks.

Public health significance and occurrence of hepatitis D

Hepatitis D occurs worldwide. It is most prevalent in countries and communities that have a high risk of hepatitis B, including Africa, South America, Romania and parts of Russia; among haemophiliacs, people who inject drugs and others who come in frequent contact with blood; in institutions for the developmentally disabled; and, to a lesser extent, among men who have sex with men.

Outbreaks have been reported in tropical South America (Brazil, Colombia, Venezuela), in the Central African Republic, and among people who inject drugs in the United States.

In recent years, as the prevalence of chronic hepatitis B surface antigen (HBsAg) carriers has decreased, there has been a decline in both acute and chronic HDV in the Mediterranean area (Greece, Italy, Spain) and in many other parts of the world. Better sanitation and social standards may have also contributed to the decline.

New areas of high HDV prevalence continue to appear and include Albania, areas of China, northern India and Japan (Okinawa).

Despite high rates of hepatitis B in Asian countries, the incidence of hepatitis D is lower. Hepatitis D is uncommon in Australia. An average of 13 cases has been reported per year in Victoria since 2010.

Reservoir of hepatitis D virus

HDV is unable to infect a cell by itself and requires co-infection with HBV to undergo complete replication. Therefore, humans with HBV infection act as reservoirs.

Mode of transmission of hepatitis D virus

HDV is transmitted by the same methods as HBV: exposure to infected blood and serous body fluids; and contaminated needles, syringes, blood and plasma product transfusions. Sexual transmission may also occur but is less common than with HBV.

Period of communicability of hepatitis D

Blood is potentially infectious during all phases of active hepatitis infection.

People infected with HDV are thought to be most infectious before the onset of acute illness. Following onset of acute symptoms, viraemia probably falls rapidly to low or undetectable levels.

Susceptibility and resistance to hepatitis D

All people who are susceptible (nonimmune) to HBV infection or those who have chronic hepatitis B can be infected with HDV.

Control measures for hepatitis D

Preventive measures

Prevention of HBV infection with hepatitis B vaccine prevents infection with HDV. For people with chronic HBV infection, the only preventive measure is avoidance of exposure to potential sources of HDV.

Studies suggest that measures to decrease sexual exposure and use of nonsterile injecting equipment are associated with a decline in the incidence of HDV infection.

Control of case

There is no specific treatment for hepatitis D, although pegylated interferon has been shown to be of some benefit.

Expert advice for ongoing management should be sought from a gastroenterologist or an infectious diseases physician.

Isolation is not required.

Educate patients about safe injecting practices and safe sex.

Control of contacts

Initiate contact tracing with the patient.

Susceptible sexual, injecting and household contacts should be offered hepatitis B vaccine.

Vaccination against hepatitis B prevents HDV infection.

Control of environment

Not applicable.

Outbreak measures for hepatitis D

Not applicable.