Hepatitis D is caused by the hepatitis virus D (HVD), and it is the smallest virus known to infect humans. Viruses in general are simple organisms; they consist of nucleic acid (be it RNA or DNA) and proteins encapsulating the acid. HVD, however, is even more simple than most viruses. The nucleic acid it contains (RNA) is so simple that it's not able to cause an infection on its own. Hepatitis D needs help from another virus — hepatitis B — to do so.
It is estimated that about 20 million people have hepatitis D worldwide. Some regions have a higher occurrence of the disease than others — hepatitis D is most prevalent in the Middle East, Mediterranean region, sub-Saharan Africa, Greenland, Japan, Mongolia, Viet Nam, Pakistan, Chinese Taipei, Kiribati, Nauru, Turkey and the northern parts of South America.
Hepatitis D: Infection and transmission
Because the hepatitis D virus is so simple, it is not able to code all of the proteins it needs for replication, so it needs the hepatitis B virus to do the rest of the work. Hepatitis D literally steals those proteins from hepatitis B. If the hepatitis B virus isn't present, the virus will not be able to replicate, and there will be no infection.
Depending on which of these two situations occur, two different types of disease follow. If a person catches hepatitis B and D at the same time (this is called co-infection), the likelihood of the infection becoming chronic is a relatively small five percent. But, if a person contracts hepatitis D while already suffering from a chronic hepatitis B infection (this is called a superinfection), the risk of the disease becoming chronic rises to a whopping 90 percent. And the outcome of these two forms of the disease differs largely.
In the case of an acute infection, the symptoms may be dramatic, but the infection usually clears itself from the organism within a few months. In two to 20 percent, it can cause acute liver failure. On the other hand, a chronic infection is a life-long disease. The symptoms may be mild at the start, but the disease progresses towards cirrhosis and hepatocellular carcinoma fast. Hepatitis D may be the rarest of all viral hepatitises, but it's also the deadliest.
Hepatitis D is spread by blood and other bodily fluids, such as saliva, vaginal and menstrual fluids, or semen. Common ways of infection include:
- Having unprotected sex
- Sharing a needle or a syringe
- Getting a tattoo or a piercing
It is also possible for an infection to pass from mother to child during childbirth, but this isn't very common.
Risk groups: Who is most likely to become infected with hepatitis D?
First of all, if a person is infected with HVB, he or she is at risk of catching a HDV infection. Other risk groups include:
- Sex workers
- IV drug users
- People who travel to regions with a higher prevalence of the disease
- Medical professionals
- People receiving blood transfusions
Symptoms of hepatitis D
The symptoms of a hepatitis D infection are similar to other diseases of the liver, and include:
- Loss of appetite
- Abdominal pain
- Light colored feces
- Dark urine
Prevention: How do you avoid hepatitis D?
There is no vaccine against this disease. But, since it needs hepatitis B virus to cause an infection, an effective way to prevent hepatitis D is getting a hepatitis B vaccine. Other than a vaccine, a person can lower their risk of getting an infection by other means, including:
- Practicing safe sex
- If you are a IV drug user, you shouldn't share needles and syringes
- If you want to get a tattoo or a piercing, do it in a clean place with new and/or sterilized equipment
- Avoid contact with blood and other bodily fluids
Since this is also a professional disease, medical staff should always use protection and handle possible sources of infection with caution.
All these preventative measures can lower your odds of getting a hepatitis D infection, but vaccines are the most efficient way of protecting yourself.
Diagnosis: How does your doctor check for hepatitis D?
If you suspect that you might have hepatitis D, based on your history and the symptoms, you should go to the doctor. The doctor will draw blood and search for anti-HDV anti-bodies. Detection of the viral RNA is also possible.
Treatment: How is hepatitis D managed?
Different types of treatment have been tried, with little to no success. Interferons may be used to slow down the progression of liver deterioration, but these drugs will not cure or stop the infection. In cases of acute liver failure, or cirrhosis, liver transplantation is the only option. Scientists are currently working on a few new medicines to fight this disease, with promising results.