Amongst the major infectious diseases, hepatitis is one of the most important diseases affecting a huge number of populations worldwide. Hepatitis is majorly caused by virus or other contributors to the inflammation of liver. It can be infectious or non-infectious. It is a big concern to deal with the disease as it is responsible for taking huge tolls of life with its remarkable symptoms in function loss of the liver due to factors like liver scarring (cirrhosis) or liver cancer (hepatocellular carcinoma) in extreme cases (NHS, 2016). Viral hepatitis is considered to be the cause of hepatitis occurrence in more than 50% cases (Buggs, 2016).
History
The discovery of hepatitis viruses dates back to times after World War II with hepatitis A virus being identified first in 1970’s (Trepo, 2014). The virus B came with the development of initial vaccines that was developed by recombinant DNA technology. This vaccine even possesses an anti-cancer capability through prevention of hepatic carcinoma. Another success was vaccines against A and E hepatitis viruses. The C virus was identified using molecular techniques in 1989. Since then there has exemplary development in vaccination and therapy development offering cure against chronic hepatitis C virus and prospects for other virus types are also positive (Trepo, 2014).
Epidemiology
Hepatitis B and C illnesses are major causes for chronic hepatitis cases and causation of death due to liver damage worldwide as it may lead to liver cancer. Liver cancers are the most common cancer occurring with a rate of ~8% in males and ~6.5% in females (Serag, 2012). Hepatocellular carcinoma is the main cause for liver cancer cases with HBV and HCV as major causes, the existence of which can be seen in figure 1 at global level.
Figure 1. HBV & HCV virus prevalence worldwide (Serag, 2012).
Hepatitis B infections are hugely age dependent and around 90% cases in children go chronic compared to 5% in adults (CDC, 2015). It is most prevalent and infects 350 million people worldwide of which around 5 lakh people reach mortality (WHO, 2016). Out of these, 1.5 million cases are seen in United States where ~5000 people reach mortality. Hepatitis C infections are mostly seen to be chronic in more than 80% cases with the infection going long term. Sub Saharan Africa and Eastern Asia are mostly seen to be affected with this carcinoma followed by southern European countries and least cases found in North & South America, Northern Europe and Oceania (Serag, 2012). A surprising fact has been reported whereby United States, Canada are recording an increase, whereas China, Japan, Hong Kong, Singapore are experiencing a decrease in disease incidences. Men are more affected than women and a high man: women ratio is seen in high occurrence countries as depicted in figure 2.
Figure 2. Global men and women record for hepatitis causing liver cancer occurrence as per age standardization in one lakh person-year (Serag, 2012).
Symptoms
Liver being the largest organ in the human body, it is responsible for storing energy from the food ingested and getting the body rid of any toxic chemicals, drugs and any other unwanted substances from the body. It is also involved in absorbing fats and vitamins for the body functioning along with protein production for blood clotting. Since, the disease leads to liver damage, the symptoms occurring in acute as well as chronic cases are related to liver. These include jaundice leading to yellowness of skin and eyes, appetite loss, urinary color changes to dark, bowel movements becoming pale & grey, diarrhea, continuous vomiting, nausea, stomach & abdominal pain, persistent pain in joints and muscles (NIH, 2014). The symptoms are not common for all the cases and others may also experience high fever with a feeling of being tired and sick at all times along with swelling of legs and feet (NHS, 2016).
Causes
Hepatitis can be caused by infectious as well as non-infectious reasons. The former includes viruses as the foremost cause along with bacterial and fungal sources. Though, hepatitis viruses are the most common cause behind hepatitis occurrence but factors like alcohol consumption, autoimmune responses or toxic ingestion also contribute in causing hepatitis.
Hepatitis Viral Types
Hepatitis has many causes as it is characterized by the liver inflammation and damages so caused to the biggest organ in the body. The viral causation is found to be very common. There are many viral types and depending on them, the hepatitis is differentiated clinically into hepatitis A, B, C, D or E. Liver inflammation being the common resultant of all of these infections but other varying factors may result. The types A and E are transmissible in unhygienic conditions via contaminated water and food sources and the types B, C and D are transferred via body fluids like blood, semen that are already infected with the virus (WHO, 2016).
Hepatitis A virus are not known to cause severe infections and people recover with resistance from further infections from HAV due to development of antibodies and is most common in poor sanitation areas. It is also transmitted from one person to another and via fecal-oral route (CDC, 2015). Hepatitis B virus is mostly transmitted through infected body fluids making the healthcare and medical professionals at great risk along with the individuals visiting such arenas. Similarly, Hepatitis C virus is transmitted via fluids along with certain cases seen through sexual transmission. Hepatitis D (also known as “Delta Hepatitis”) viral infection is interesting as it infects only HBV affected cases and a cure against B virus works for D as well (WHO, 2016). HDV cannot complete its life cycle as it requires components from HBV for replication (CDC, 2015). Hepatitis E virus spreads through unhygienic conditions of food and living and being mostly prevalent in developing countries.
Diagnosis
After studying the symptoms of the infected person, the blood tests are conducted to detect hepatitis occurrence. Blood tests are performed to test for liver enzymes i.e. aminotransferases like aspartate aminotransferases (SGOT) and alanine aminotransferases (SGPT). Their rising level in blood (>40 units per liter of serum for SGOT & >56 for SGPT) is a true indication of liver damage. To be sure of hepatitis being the reason for liver damage, antibodies and viral genetic material presence are tested. Imaging studies like CT scan, sonography along with liver biopsy are used to identify chronic cases.
Treatments & Cure
Irrespective of the cause behind hepatitis occurrence, the patients need to be treated carefully as transmission from infected tissues and body fluids is a major cause behind disease transmission. Careful management of medical instruments, equipment, and all the materials involved in treatment is needed in order for prevention of hepatitis further. Washing hands after using washrooms, diaper changing, before eating food and many such hygienic measures reduced the risk of contracting hepatitis considerably. The advances in molecular techniques and genetic engineering tools have opened new gateways to curb and cure the hepatitis viral diseases to great extents. The HCV virus has been treated well initially with interferon therapy moving on to triple combination therapy with a success rate of 80% in 2013 (Trepo, 2014).
Vaccines have been developed against all serotypes of hepatitis viruses but HCV. In fact, the vaccine against HBV works as dual rescuer and protects against HDV as well. The best cure is to get the vaccination done for serotypes prevalent in a region for the children from a younger age. There are several standard medications used to treat HBV and HCV that include adefovir, lamivudine, entecavir or dipivoxil for the former and peginterferon and ribovarin combination for later (NIH, 2014).
References
Trepo, C. (2014). A Brief History of Hepatitis Milestones. Liver International. 34(1): 29-37.
Serag-EI, B, H. (2012 May). Epidemiology of Viral Hepatitis and Hepatocellular Carcinoma. Gastroenterology. 142(6):1264-1273.
NHS. (2016). Hepatitis. Retrieved 20 May 2016 from http://www.nhs.uk/conditions/Hepatitis/Pages/Introduction.aspx.
WHO. (2016). What is Hepatitis? Retrieved 22 May 2016 from http://www.who.int/features/qa/76/en/.
CDC. (2015). Viral Hepatitis. Retrieved 23 May 2016 from http://www.cdc.gov/hepatitis/.
NIH. (2014). Hepatitis. Medline Plus. Retrieved 25 May 2016 from https://www.nlm.nih.gov/medlineplus/hepatitis.html.
