Hepatitis D: Causes, Symptoms, Transmission, Treatment and Prevention

Hepatitis D, also known as the hepatitis delta virus, is a liver inflammation caused by the hepatitis D virus (HDV). HDV is considered a hybrid virus because it uses the hepatitis B surface antigen (HBsAg) as an envelope protein, and therefore, it is only capable of infecting patients who are co-infected with HBV.

Hepatitis D infection cannot occur in the absence of the hepatitis B virus. HDV-HBV co-infection is considered the most severe form of chronic viral hepatitis due to its more rapid progression toward hepatocellular carcinoma and death.

Vaccination against HBV prevents HDV co-infection; therefore, the expansion of immunization programs through approved vaccination schedules has led to a decrease in the incidence of hepatitis D worldwide.

Mode of transmission

Transmission routes for HDV, like those for HBV, involve broken skin or contact with infected blood or blood products. Mother-to-child transmission is possible but rare.

Chronic HBV carriers are at risk of HDV infection. People who are not immune to HBV (either through having had the disease or through immunization with the hepatitis B vaccine) are at risk of HBV infection, which in turn puts them at risk of HDV infection.

Among those who are more susceptible to HBV and HDV co-infection are Indigenous people, people who inject drugs, and people with hepatitis C virus or HIV infection. Additionally, the risk of co-infection appears to be potentially higher in people receiving hemodialysis, men who have sex with men, and sex workers.

Symptoms

Hepatitis D can be acute or chronic. Acute hepatitis D occurs suddenly and usually causes more severe symptoms. It may resolve on its own.

If the infection lasts for six months or longer, the condition is known as chronic hepatitis D. The long-term version of the infection develops gradually over time. The virus might be present in the body for several months before symptoms appear. As chronic hepatitis D progresses, the chances of complications increase. Many people with this condition eventually develop cirrhosis or severe liver scarring.

Symptoms usually appear 3–7 weeks after the initial infection and include fever, fatigue, loss of appetite, nausea, vomiting, dark urine, jaundice, and even fulminant hepatitis.

However, recovery is usually complete, the development of fulminant hepatitis is infrequent, and chronic hepatitis D is rare.

In cases of superinfection, HDV can infect a person already chronically infected with HBV. HDV superinfection accelerates the progression toward a more severe form, regardless of age.

HDV superinfection accelerates the progression toward cirrhosis nearly a decade earlier than in people monoinfected with HBV. Patients with HDV-induced cirrhosis are at an increased risk of hepatocellular carcinoma (HCC); however, the mechanism by which HDV causes more severe hepatitis and faster fibrosis progression than HBV alone remains unclear.

Diagnosis

HDV infection is diagnosed by detecting high levels of anti-HDV immunoglobulin G (IgG) and immunoglobulin M (IgM) and confirmed by detecting HDV RNA in serum.

Treatment

Pegylated interferon alpha is the recommended treatment for hepatitis D virus infection. Treatment should last for at least 48 weeks, regardless of the body's response. The virus tends to show a low response rate to treatment; however, treatment is associated with a lower probability of disease progression.

This treatment is associated with significant side effects and should not be administered to patients with cirrhosis, active psychiatric conditions, or autoimmune diseases.

In the case of cirrhosis or other types of liver damage, you may need a liver transplant, which involves removing the damaged liver and replacing it with a healthy liver from a donor.

Prevention

Although there is no vaccine available for hepatitis D, vaccination against hepatitis B can protect people from potential HDV infection.

You can take the following preventive measures to reduce the risk of hepatitis B, and consequently, D:

• using condoms during sexual intercourse
• avoiding recreational drugs that can be injected, such as heroin or cocaine
• using sterile needles and syringes every time medications are administered
• avoid getting tattoos in locations that have poor hygienic and sanitary conditions

References
https://www.nfid.org/infectious-diseases/hepatitis/
https://www.who.int/news-room/fact-sheets/detail/hepatitis-d
https://www.cdc.gov/hepatitis/hdv/hdvfaq.htm#section5
https://www.healthline.com/health/delta-agent-hepatitis-d
https://www.ncbi.nlm.nih.gov/books/NBK470436/
https://www.webmd.com/hepatitis/hepatitis-d-overview