World Hepatitis Day 2014

5279776905_4f0477d2fc_zToday is World Hepatitis Day, which is marked by the World Health Organization (WHO) to raise awareness of a disease that continues to claim millions of lives around the world every year. Predominantly a viral disease, hepatitis is primarily characterised by an inflammation of the liver, followed in many cases by liver cirrhosis, liver failure or liver cancer.

There are five different hepatitis viruses, known as A, B, C, D and E, which all cause a different variant of the disease. All five hepatitis viruses can cause short-term (“acute”) infection; hepatitis B, C and D infections can also be long-term, or chronic, and may cause liver cancer and liver failure. An estimated 1.5 million people die of hepatitis infections every year, with Hepatitis B and C causing the large majority of these deaths.

Besides the viruses themselves, a number of other factors can also cause hepatitis or increase predisposition to it. Long-term excessive alcohol consumption and some medications and antibiotics increase the likelihood of liver cirrhosis and liver failure. Those with impaired immune systems may experience autoimmune hepatitis, where the body attacks its own liver cells. Finally, some 40% of all babies born to mothers who suffer from hepatitis B also have the disease. A vaccination is required within the first few hours after birth to prevent a continued infection in the child.

In England, hepatitis C is the most common type of viral hepatitis, affecting some 215,000 people. It is mostly spread through sharing needles for intravenous drug use, and many people are unaware that they have the virus, as the disease rarely exhibits symptoms early in the infection. In 75% of cases, the virus stays in the body and causes chronic hepatitis C, which can lead to liver cirrhosis and liver failure. There is no vaccine against hepatitis C, and while antiviral medication does exist, it can have very unpleasant side effects.

Hepatitis B, which is mainly transmitted through blood and other bodily fluids, is one of the most widespread infectious diseases worldwide. The WHO estimates that 240 million people suffer from chronic hepatitis B and 780,000 die every year, making it a major global health problem.

In areas of low hepatitis B prevalence, such as Western Europe and the US, where 0.5-2% of the population are infected, the primary routes of infection include intravenous drug use and unprotected sex. In high-prevalence areas like China and Southeast Asia, the disease is mainly spread during childbirth or in early childhood due to sanitary problems.

While acute hepatitis B infections often clear spontaneously and without medication, the disease can be very severe if it becomes chronic. What’s more, the infection is more likely to become chronic the younger the infected person is. Hepatitis B is also a prerequisite for infection with the hepatitis D virus, which further increases the risk of liver cancer.

There is no known cure for hepatitis B. Antiviral drugs can slow the onset of liver cirrhosis and improve survival prospects in the long run, and liver transplants are sometimes undertaken. Such treatments, however, are rarely available in lower-income countries.

As such, the main focus of the WHO is on prevention. The hepatitis B vaccine is safe and reliable, and over a billion doses have been given since 1982. The WHO also works to raise awareness, improve surveillance and establish control programmes such as the Safe Injection Global Network.

Jon Fuhrmann

Image Credit: Sanofi Pasteur on Flickr
This entry was posted in Clinical and Medical Microbiology, Virology and tagged , , , . Bookmark the permalink.

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