Hepatitis D is one of the least-discussed but most fascinating of all hepatitis viruses. Tirst discovered in 1977, hepatitis D is considered to be the very smallest disease-causing virus in humans.
This particle is so small and so simple that it is not able to cause an infection on its own. Instead, hepatitis D needs hepatitis B to replicate and infect the liver. Once the virus enters a liver cell, it suppresses the replication of the hepatitis B virus and hijacks some parts hepatitis B coded for its own assembly.
This disease is spread via contact with infected blood, and using IV drugs unsafely or being exposed to other bodily fluids are two of the main ways of contracting hepatitis D. Although it isn't very common, the infection can be passed from mother to child during childbirth as well.
It is estimated that there are around 20 million people currently living with hepatitis D worldwide. The symptoms of this disease aren't different from those of other hepatitis viruses, both infectious and non-infectious. They include, among others:
- Pain in the upper right quadrant of the abdomen
- Pale stool
- Light urine
- Joint pain
- Loss of appetite
- Nausea
- Weight loss
- Jaundice
A hepatitis D infection can strike only in the presence of the hepatitis B virus. This might seem like a long shot, but considering that both viruses share the same means of transmission and that both types of hepatitis are strongly linked to IV drug use and risky sexual behavior, it comes as no surprise that about five percent of people who are hepatitis B positive suffer from hepatitis D as well.
Hepatitis D: Coinfection vs superinfection
A hepatitis infection D can occur in two different situations.
- If a person is exposed to both hepatitis B and D at the same time, it is known as a coinfection.
- When a person already has an existing hepatitis B infection and encounters the hepatitis D virus later, it's known as a superinfection.
In the case of coinfection, when a person is infected with both viruses at the same time, more than 90 percent of adults will develop an acute form of the disease. In this form of the disease, the virus spontaneously clears out of the organism within six months.
Chronic hepatitis B patients are, on the other hand, at much greater risk of developing a chronic hepatitis D infection. In the case of superinfection, up to 90 percent of patients develop a chronic form of the disease. A chronic hepatitis D infection is a very aggressive form of disease, with up to 70 percent of patients developing cirrhosis not long after contracting the virus. The reason behind the faster progression of the disease is yet to be discovered.
How can hepatitis D be treated?
The treatment of this disease depends on the form the disease takes. If an acute form of the infection is present, specific therapy usually isn't needed. The chronic form of the disease, on the other hand, requires intense therapy. Although interferon therapy is available, unfortunately, the response to this therapy is low. Liver transplantation is an option, if an acute liver failure occurs, or in the case of cirrhosis.
As for prevention, there is unfortunately no vaccine to protect you from hepatitis D. However, since the hepatitis D virus relies on the presence of the hepatitis B virus to cause an infection, a vaccine for hepatitis B can protect us from this form of viral hepatitis as well.
The other ways of staying safe from the infection, aside from immunization, include always using new, sterile needles (this applied to medical settings as well as to IV drug users and people getting tattoos), practicing safe sex and only receiving blood transfusions at facilitates that have tested for the presence of hepatitis D. Since even the smallest amounts of infected blood can cause an infection, it is also advised not to share personal equipment, such as razors or toothbrushes.
The good news is that there are fewer people infected with hepatitis D now than there were in the 1980s. There are several reasons for this, such as regular testing of the blood used for transfusions and increased popularity of condom use, but overall, the worldwide use of the hepatitis B vaccine is considered to be the main reason for the lowered number of people affected.