Abstract
Hepatitis caused by viruses is a leading source of morbidity and mortality globally, especially in the tropical region. It's caused by five different viruses, each with its own molecular properties and replication cycles, but all with a similar liver tropism and illness patterns that overlap. Since the liver is a vital organ it is very necessary to understand this liver disease, it's symptoms, diagnostic measures and prevention. In 2020, the Nobel Prize in Physiology rewards an effort that eventually made blood transfusion safer for everyone.
Keywords
Chronic, Antivirals, Vaccine, Cirrhosis, Biopsy.
Introduction
The liver is a significant organ found solely in vertebrates that conducts a variety of vital biological tasks. [1][2][3] The liver is essential for removing toxins from the blood, storing vitamins and producing hormones. Hence the protection of the liver is as important as protecting your heart. However hepatitis , a liver inflammation can disrupt all the functions of the liver. Hepatitis is classified as either an acute (short-term) infection or a chronic (long-term) infection.[4 ] Hepatitis is commonly caused by hepatitis virus but it can also be caused by infections, toxic substances such as alcohol, certain drugs and autoimmune diseases.[5] The letters A, B, C, D, and E stand for five distinct hepatitis viruses discovered by scientists. Hepatitis A and E are primarily transmitted through contaminated food and water and Hepatitis B is transmitted through sexual contact and from infected mother to child during pregnancy.[6] Hepatitis C is normally spread when exposed to infected blood as when intravenous drug users share needles. Only persons who have already been affected with Hepatitis B can get Hepatitis D.[7] In 2020 the Nobel Prize for Physiology has been awarded to Harvey J. Alter, Michael Houghton and Charles M. Rice for their discovery of the Hepatitis C virus. According to the Nobel Prize committee statement, the prize is granted to crucial contribution to the fight against blood-borne hepatitis, a serious worldwide health concern that causes cirrhosis and liver cancer in people all over the world.[8] This article covers the symptoms, diagnosis and other major points about Hepatitis C virus which can be abbreviated as HCV and the significance of Nobel Prize in Physiology in 2020.
Symptoms
Two weeks to six months is generally the incubation period of hepatitis C which is the time taken by the symptoms to first appear on an infected individual.[5] After the initial infection, around 80% of patients do not develop any symptoms. Symptoms of acute
illness include fever, tiredness, decreased appetite, nausea, vomiting, abdominal discomfort, dark urine, pale excrement, joint pain, and jaundice (yellowing of skin and the whites of the eyes).[5]
Transmission
The bloodborne virus, HCV is transmitted through the reuse or lack of sterilization of medical equipments particularly syringes and needles in hospitals, the transfusion of unscreened blood and blood products and intravenous drug use. It can be spread from a mother to her child who is infected, as well as through sexual practices that expose the victim to blood. HCV is not spread through breast milk, food, water, or informal contact with an infected individual, like hugging, kissing, or sharing food or drinks.[5]
Diagnosis
The new HCV infections are frequently asymptomatic, only a small percentage of persons are diagnosed when they are first infected.[5]In general, the person's blood tests and clinical picture are sufficient for diagnosing viral hepatitis and other acute causes of hepatitis.[9][10] Blood tests may not be beneficial for other types of hepatitis, particularly chronic ones. The benchmark for determining the diagnosis in this situation is a liver biopsy.[10] The only definitive diagnostic test for assessing liver inflammation and fibrosis is a liver biopsy. Although liver biopsy cannot be considered as an initial diagnostic test because it is invasive and has a significant risk of bleeding that is increased in people with liver injury and cirrhosis.[11]If the test is positive for anti-HCV antibodies, a nucleic acid test for HCV ribonucleic acid (RNA) is needed to confirm chronic infection because about 30% of people infected with HCV spontaneously clear the infection by a strong immune response without the need for treatment.[5]
Treatment
The Hepatitis treatment differs depending on the kind of hepatitis, whether acute or chronic, and the severity of the condition. A fresh HCV infection does not always require treatment, as some people's immune systems can eliminate the infection. When HCV infection becomes chronic, however, therapy is required. For people over the age of 12, the WHO recommends using pan-genotypic direct-acting antivirals (DAAs). Most people with HCV infection can be cured with DAAs, and therapy takes only a few weeks (typically 12 to 24 weeks), depending on the absence of presence of cirrhosis.[5]
Hepatitis patients should avoid taking liver metabolized drugs like Glucocorticoids which may even be harmful, causing chronic hepatitis.[9]
Prevention
Since there is no effective vaccine for hepatitis C, prevention depends on lowering the risk of infection in health-care settings and among higher-risk populations. This includes people who inject drugs and men who have sex with other men, especially those who are HIV-positive or taking HIV pre-exposure prophylaxis.[5] Using sterile syringes and needles as well as testing of blood are also some of the preventive measures.
Epidemiology
This disease affected 130-180 million people in the world, which is around 3% of the world population.[12][13][14] An estimated 58 million people worldwide are infected with the chronic hepatitis C virus, with 1.5 million new infections occurring each year.[5] According to the World Health Organization, over 290,000 individuals died with hepatitis C in 2019, the majority of them died from cirrhosis and hepatocellular carcinoma (primary liver cancer). The Eastern Mediterranean and European regions have the highest disease burdens, with 12 million chronically infected people in each. An estimated 10 million people in each of the South-East Asia and Western Pacific regions are chronically infected. The African Region has nine million chronically infected people, while the Americas Region has five million.[5] Most chronic carriers of hepatitis C are not aware of their infection status.[9]
Exposure to blood products via blood transfusions (prior to 1992) and intravenous drug injection is the most common mechanism of hepatitis C virus transmission.[9][13]
Nobel Prize in Physiology 2020
The three Nobel laureate have significant role in the discovery. Harvey Jalter demonstrated that an unknown virus was a common cause of chronic hepatitis. Michael Houghton isolated the genome of the new virus which was named Hepatitis C virus. Charles M Rice provided the evidence showing that Hepatitis C virus alone could cause Hepatitis. This groundbreaking discovery paved the way for the development of screening procedures that have drastically lowered the danger of acquiring hepatitis through contaminated blood, as well as efficient antiviral medications that have improved the lives of millions of people.[15]
Conclusion
Validated tests that identify HCV carriers and allow the elimination of contaminated blood and blood products are widely available around the world, which is the result of work of Alter, Houghton, and Rice, as well as many colleagues who built on their
findings. The effective drugs have changed the fate of HCV infected patients. HCV-induced hepatitis is now a treatable condition in many cases, and the lesions caused by infection are frequently reversible.
Reference
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