The Seat of The Soul
While current culture talks about matters of the heart, stemming from the idea in the middle ages that the heart is the seat of emotion, ancient Greeks and surrounding cultures believed that the liver was the seat of the soul. Even in Shakespeare’s age this view was still referenced with words such as lily-livered (white and bloodless liver making a coward) entering the language. In Henry IV Part 2, Shakespeare has Pistol say to Flagstaff “I will inflame thy noble liver, / And make thee rage”.
It was often hepatitis that contributed to this view. Doctors in the ancient world noted a change in temperament in those with liver disease, they became grumpy and depressed and so the obvious conclusion was that a healthy liver was required for emotional well-being.
Skip forward a few millennia and we now know that the liver, while not responsible for the soul or emotions, is an essential organ for overall health, serving metabolic, detoxing and storage functions for the blood and gastrointestinal system. Most drugs are metabolised in the liver and it plays an important role in the metabolism of alcohol and fat. The use of strong prescription drugs, drug abuse, alcohol and a fatty diet can all damage this vital organ. Indeed, few organs have the fortitude of the liver to survive what we throw at it. Its regenerative properties are incredible, it can function and indeed regrow even if there is only 20% of the organ left intact.
The Liver’s Nemesis
But the most common cause of liver damage is not lifestyle choices or unfortunate genetic diseases. It is the result of five very nasty viruses, imaginatively named Hepatitis A-E. The Hepatitis viruses are grouped together based on their effects on the body, they are indeed a group of unrelated viruses that vary from large DNA viruses to RNA retroviruses.
Hepatitis A (HAV) has the scientific name of Hepatorvirus hepatovirus A and is from the Picornaviridae family. It is a small single-stranded RNA virus and though it has multiple genotypes there is only one serotype of this virus. HAV does not produce a lipid envelope, leaving the peptide casing exposed to the immune system. Hepatitis A vaccine is effective against all genotype variants. This virus is spread by the faecal route, in contaminated food or water. It is not sexually transmitted and while it causes acute hepatitis it does not cause chronic disease and is usually cleared by the body naturally within two weeks.
Hepatitis B (HBV) is the best-known hepatitis virus. It is a blood-borne virus that has an acute hepatitis phase when the person is first infected but then goes on to cause chronic hepatitis. While the hepatitis is manageable, the chronic inflammation can cause cirrhosis of the liver (scarring) and can lead to liver cancer. The scientific name of HBV is Orthohepadnavirus hepatitis B virus and it is one of the smallest DNA viruses known. Unlike the simpler HAV, HBV has an outer lipid envelope which aids its entry to cells and increases its effectiveness against the immune system. Hepatitis B can be sexually transmitted much more easily than HIV.
The first Hepatitis B vaccine was approved in 1981 and the current recombinant vaccines provide protection against Hepatitis A and B. It is impossible to contract HAV or HBV from the vaccine. To make the vaccine, viral proteins that stimulate the immune system to react and destroy the Hepatitis viruses are produced from viral genes in yeast cells, purified then prepared for the vaccine. There are two shots required and a blood test is given after vaccination to confirm the presence of protective antibodies. It is currently thought that the vaccine provides lifelong immunity to the virus and it safe to give to newborns.
Hepatitis C is the most dangerous of the viruses with regards to the development of liver cancer. It is sexually transmitted but most commonly contracted by sharing needles. HCV is Hepacivirus hepatitis C virus and is a small single-stranded RNA virus that possesses a lipid envelope and member of the Flaviviridae family. As well as liver cells, HCV can infect lymphocytes (a white blood cell) and can cause lymphatic cancer as well as liver cancer. There is no vaccine for HCV but the advances in antiviral medication has shown huge successes in recent years and now an aggressive treatment with antivirals can produce up to an 80% cure rate.
Hepatitis D (HDV) is a strange one. It is an RNA virus and the smallest virus known to infect humans. It does not infect on its own and is only ever seen as a co-infection with HBV. Deltavirus hepatitis delta virus accelerates the liver damage caused by HBV. The presence of HDV significantly increases the fatality levels related to hepatitis and cancer incidence. As it is only possible to contract HDV if infected with HBV, vaccine protection against HBV works indirectly to protect against HDV. HDV is most commonly transmitted by infected blood, shared needles and blood transfusions. It is not clear if it is sexually transmitted.
Hepatitis E (HEV) is similar to HAV in transmission and disease presentation. A non-encapsulated RNA virus with the scientific name Orthohepevirus orthohepevirus A, HEV is transmitted by the faecal-oral route and causes and acute infection lasting 3-8 weeks. It normally has a 2% fatality rate but this rises to 20% in women in the third trimester of pregnancy. HEV is seen predominately in third world countries and because of this, vaccine production has been halted in most of the first world countries. China has an active vaccination program against HEV but is the only nation to produce a commercial vaccine for HEV.