Hepatitis D is a disease caused by the hepatitis D virus (HDV), a ribonucleic acid (RNA), that affects the liver. Hepatitis D requires hepatitis B virus for its replication and cannot happen in its absence. In most cases the patient is usually infected only with hepatitis D virus but hepatitis B virus is also present. Getting infected with both hepatitis D virus as well as hepatitis B virus causes a more severe infection. A vaccine against hepatitis B is the only method to prevent hepatitis D virus infection. Before we discuss more about hepatitis D causes or signs of hepatitis D, let’s understand more about the geographic distribution of the disease.
According to WHO estimates, around 5% of HBsAg, the surface antigen of hepatitis B virus, infected people globally are co-infected with hepatitis D virus. Around 15 million people have chronic simultaneous hepatitis D virus infection and hepatitis B virus infection. The distribution of the disease is worldwide with high-prevalence areas including the Mediterranean, Middle East, Central and Northern Asia, Pakistan, Japan, Taiwan, Greenland and parts of Africa, the Amazon Basin and certain areas of the Pacific. The prevalence of hepatitis D virusis low inNorthern Europe, North America, South Africa, and Eastern Asia. Chronic hepatitis B virus carriers are at high risk for infection with hepatitis D virus.
Since HDV infection needs a person to be infected with HBV first, people who are not immune to HBV are also at risk of HDV infection.Acute hepatitis D occurs suddenly and may go away on its own. When the hepatitis D infections lasts for more than six months, it is called chronic hepatitis D virus infection. The long-term version of the infection develops gradually over time. The virus might be present in the body for several months before any symptoms of the infection occur. As chronic hepatitis D progresses, the chances of complications increase. Many people with the condition eventually develop cirrhosis, or severe scarring of the liver.
Hepatitis D virus is usually either acute infection caused by simultaneous infection with hepatitis B virusand hepatitis D virus or superinfection caused by hepatitis D virus infection when a person already has chronically hepatitis B infection. The signs and symptoms of acute hepatitis D virus infection are usually more severe and lead to mild-to-severe or even fulminant hepatitis. Only less than 5% people with acute HDV infection develop chronic hepatitis D. The recovery in most cases is complete.In case of superinfection the symptoms usually include chronic hepatitis B progression to a more severe disease in around 90% people of all ages. The most common symptoms of hepatitis D virus infection include yellowing of the skin and eyes, which is called jaundicejoint pain, abdominal pain, loss of appetite, coloured urine, fatigue and vomiting.
The routes of hepatitis D virus transmission are the same as for hepatitis B virus; sexually or percutaneously through contact with infected blood or blood products or body fluids such as semen, vaginal fluids, urine of an infected person. Vertical transmission is rare but possible. Vaccination against hepatitis B virus prevents coinfection by hepatitis D virus, and increasing childhood immunization programmes have resulted in decline in hepatitis D incidence worldwide. However, in some cases especially among people who inject drugs the hepatitis D prevalence has been observed to increase. Vertical transmission of hepatitis D virus infection from mother to child is also possible but rare.
Hepatitis D virusinfection is diagnosed by detection of high traces of Immunoglobulin G (IgG) and Immunoglobulin M (IgM) anti-HDV. The diagnosis is then confirmed by the detection of hepatitis D virus RNA.However, the diagnostics for hepatitis D virus are not widely available, moreover there is no standardization for HDA RNA assays, making the diagnosis difficult.
Although there is no specific antiviral treatment available for acute or chronic hepatitis D virus infection, persistent hepatitis D virus replication can be treated with antiviral therapy. Persistent HDV replication can cause mortality if not treated timely with an effective antiviral therapy. Pegylated interferon alpha is the only drug effective against hepatitis D virus. The antiviral drugs used for hepatitis B virus have limited or no effect on HDV replication. The period of the therapy nor the period for which long patients need to be HDV RNA negative after the therapy are not well defined. Usually antiviral therapy may be necessary for over 1 year. The overall rate of sustained virological response is quite low with most patients relapsing after discontinuation of therapy. In cases of fulminant hepatitis or another underlying liver disease, liver transplantation may be considered.
The effective prevention and control of hepatitis D virus infection requires prevention of hepatitis B virus transmission which can be achieved by hepatitis B immunization, injection and blood safety, and harm reduction services. However, hepatitis B immunization does not provide protection against HDV for those already HBV infected. But HBV immunization greatly reduces the risk of HDV infection in people who are not HBV infected. To effectively reduce risk of hepatitis D virus infection, one had to always practice safe sex, useful safety measures with blood and blood products, and get vaccinated for hepatitis B virus. One also needs to be very careful when getting piercing or tattoos done. Ask the people at the tattoo parlour to sterilize the needles first.
Hepatitis D virus infection can’t be cured. Early diagnosis is essential in preventing liver damage. When left untreated HDV infection it can lead to cirrhosis, liver disease, or even liver cancer. People with chronic hepatitis D are more likely to develop complications than those with the acute version of the infection.
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