Hepatitis D is a viral infection that causes liver inflammation (swelling of the tissue which occurs due to injury or infection) and damage. Symptoms are typically similar to those of the flu, and the infection is transmitted through the sharing of contaminated needles or bodily fluids.
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Hepatitis D or hepatitis delta virus is a small ribonucleic acid (RNA) particle that causes infection only in the presence of the hepatitis B virus. It is estimated that about 15 million people carrying hepatitis B virus worldwide are infected by the hepatitis D virus.
Hepatitis D virus infection occurs in two forms: firstly, it is caused by the co-infection with hepatitis B and hepatitis D virus, and this results in a more severe acute hepatitis infection with a higher mortality rate than seen with acute hepatitis B infection alone that rarely results in chronic infection.
The second form of hepatitis D infection is a superinfection (second infection superimposed on an earlier one) of hepatitis D virus in a hepatitis B virus carrier, and can be termed as a severe “acute” hepatitis in previously asymptomatic hepatitis B virus carriers, or as an exacerbation of underlying chronic hepatitis B.
Hepatitis D virus can cause a chronic, acute or dual infection. Acute hepatitis D is a short-term infection, whereas chronic hepatitis D is a long-lasting infection. Chronic hepatitis D occurs when the body is not able to fight off the virus, and the virus does not go away. People who have chronic hepatitis B alone less prone to complications compared to those who have both chronic hepatitis B and D.
Usually, symptoms of acute hepatitis D recover within 1 to 3 months. The symptoms of chronic hepatitis D are relatively mild, and occur in waves. Most of the symptoms of hepatitis D are mistakenly referred to more common illnesses such as flu or gastroenteritis. In rare cases, patients with hepatitis D experience no symptoms at all.
Hepatitis D symptoms are not easily differentiable from hepatitis A and B infection. The symptoms of acute hepatitis D infection include:
In contrast, the population with chronic hepatitis D have fewer symptoms than those with acute hepatitis D until complications develop, which could be several years after they were infected. Some symptoms of chronic hepatitis D include:
Infection with hepatitis D virus has worldwide distribution, although, there are some considerable geographic differences which cause uneven prevalence across the globe.
In Northern Europe and the United States, where hepatitis B infection is not endemic, infection is most common in people who regularly use illegal intravenous drugs. Much of the population in these areas have been vaccinated against HBV, lowering the rate of infection further.
In the areas where hepatitis D virus is endemic, such as the Mediterranean Basin, the parenteral route is the most common cause of hepatitis D virus transmission.
Hepatitis D virus is transmitted in several ways. It can pass via blood, or contact with other body fluids such as semen, vaginal fluid, or saliva of an infected person.
Hepatitis D is not transmitted through: