Epidemiology of hepatitis D

Overview of the epidemiology of hepatitis D

Epidemiology of Hepatitis D

Global distribution of hepatitis D

Hepatitis D, also known as hepatitis delta, is a liver infection caused by the hepatitis D virus (HDV), which is a satellite virus that requires the presence of hepatitis B virus (HBV) to replicate. The epidemiology of hepatitis D is closely linked to that of hepatitis B, as HDV can only infect individuals who are also infected with HBV.

Global Prevalence

Hepatitis D is considered a major public health problem in certain regions of the world. The global prevalence of HDV infection is estimated to be around 5% among individuals who are positive for the hepatitis B surface antigen (HBsAg). This translates to approximately 15-20 million people worldwide who are co-infected with HBV and HDV.

The highest prevalence rates of hepatitis D are found in parts of Eastern Europe, the Middle East, Africa, and the Amazon Basin. In these regions, the prevalence of HDV among HBsAg-positive individuals can be as high as 60-70%. In contrast, the prevalence is much lower in North America and Western Europe, where it is estimated to be less than 1% among HBsAg-positive individuals.

Transmission

The transmission of hepatitis D occurs through the same routes as hepatitis B, primarily through exposure to infected blood and body fluids. This includes:

• Percutaneous or parenteral exposure, such as through intravenous drug use or unsafe medical practices.
• Sexual transmission, particularly among individuals with multiple sexual partners or those who engage in unprotected sex.
• Vertical transmission from mother to child during childbirth, although this is less common for HDV compared to HBV.

Risk Factors

Individuals at higher risk of HDV infection include:

• People with chronic hepatitis B infection.
• Intravenous drug users.
• Individuals with multiple sexual partners.
• Healthcare workers exposed to blood and body fluids.
• People living in or traveling to regions with high endemicity of HDV.

Clinical Implications

Co-infection with HDV and HBV can lead to more severe liver disease compared to HBV infection alone. This includes a higher risk of cirrhosis, liver failure, and hepatocellular carcinoma. The clinical course of hepatitis D can vary, with some individuals experiencing rapid progression to liver disease, while others may have a more indolent course.

Prevention and Control

Preventing hepatitis D infection primarily involves preventing hepatitis B infection, as HDV cannot replicate without HBV. This includes:

• Hepatitis B vaccination, which is effective in preventing HBV infection and, consequently, HDV infection.
• Safe injection practices and blood transfusion safety.
• Education and awareness programs to reduce risky behaviors associated with transmission.

Related Pages

• Hepatitis B
• Hepatitis D virus
• Liver disease
• Viral hepatitis