Title 17. COMMONLY OCCURRING COMMUNICABLE DISEASES - HEPATITIS.pdf ✅

PHARMD GURU Page 1 HEPATITIS INTRODUCTION: Hepatitis means injury to the liver with inflammation of the liver cells. Toxins, certain drugs, some diseases, heavy alcohol use, bacterial and viral infections can all cause hepatitis. Hepatitis is also the name of a family of viral infections that affect the liver; the most common types in the India and Asian countries are hepatitis A, hepatitis B and hepatitis C. TYPES OF VIRAL HEPATITIS: A group of viruses known as the hepatitis viruses cause most cases of liver damage worldwide. Common viruses cause hepatitis include A, B, C, D, E and G (95% cause of viral hepatitis). Other viruses include, Herpes simplex virus, Cytomegalovirus, Epstein-Barr virus, Yellow fever virus and Adenoviruses also cause hepatitis. HCV infection in India has a population prevalence of around 1%, and occurs predominantly through blood transfusion and the use of unsterile glass syringes. COMMONLY OCCURRING COMMUNICABLE DISEASES
PHARMD GURU Page 2 ETIOLOGY: Most common cause of all viral hepatitis includes:  Use of infected needle and syringes,  Intravenous drug users,  Transfusion of infected blood and blood products,  Unprotected sexual contact with an infected partner. HEPATITIS A VIRUS: Infection causes due to eating raw shellfish from water polluted with sewage and contaminated food and water. Travel or work in regions with high rates of hepatitis A. CARRIER OF HEPATITIS B VIRUS: Some people with Hepatitis B never fully recover from the infection (chronic infection), they still carry the virus and can infect others for the rest of their lives. HBV can be transmitted between family members within households by contact of non-intact skin or mucous membrane with secretions or saliva containing HBV. CAUSES OF HEPATITIS C VIRUS: Occurs as the result of percutaneous transmission of the hepatitis C virus through infectious blood. It can be passed from an infected mother to her baby. HCV can also be transmitted through household contact (sharing of personal items such as razors, toothbrushes, scissors and manicuring equipment within the same household). CAUSES OF HEPATITIS D VIRUS: HDV is transmitted parenterally, it can replicate independently within the hepatocyte, but it requires HBs Ag for propagation. Sexual transmission is less efficient than with HBV. Perinatal transmission is rare. CAUSES OF HEPATITIS E VIRUS: Infection spread by fecally contaminated water within endemic areas. On the other hand, in non-endemic areas, the major mode of the spread of HEV is food borne, especially undercooked pork.
PHARMD GURU Page 3 CAUSES OF HEPATITIS G VIRUS: It has been identified in all ethnicities, and 1% - 4% of worldwide blood donors are carriers of the virus at the time of blood donation. PATHOPHYSIOLOGY OF HEPATITIS: 1) HEPATITIS A: Hepatitis A is a highly contagious liver infection caused by the hepatitis A virus. The hepatitis A virus is one of several types of hepatitis viruses that cause inflammation that affects liver‟s ability to perform normal function. Nearly everyone who develops Hepatitis A makes a full recovery; it does not lead to chronic disease. Mild cases of hepatitis A do not require treatment, and most people who are infected recover completely with no permanent liver damage. It is small sized (27 nm), non-enveloped, single stranded RNA virus. Related to enteroviruses, (Enteroviruses are a genus of positive sense single-stranded RNA viruses) formerly known as enterovirus 72, now put in its own family heptovirus. It is very difficult to grow in cell culture: PATHOPHYSIOLOGY: After oral inoculation the virus is transported across the intestinal epithelium. After travelling through the mesenteric veins to the liver, the virus enters hepatocytes, where replication of hepatitis A virus (HAV) occurs exclusively within the cytoplasm via RNA-dependent polymerase.
PHARMD GURU Page 4 The liver damage is due to direct killing of hepatocytes and by the host‟s immune system response to infected hepatocytes indicates inflammation of liver. Microscopically there is spotty parenchymal cell degeneration, with necrosis of hepatocytes, with disruption of liver cell cords. 2) HEPATITIS B: Hepatitis B is a serious liver infection caused by the hepatitis B virus (HBV), which infects the liver and causes an inflammation called hepatitis, originally known as “serum hepatitis”. It ranges in severity from a mild illness, lasting a few weeks (acute), to a serious long-term (chronic) illness that can lead to liver cancer or cirrhosis (a condition that causes permanent scarring of the liver). Most people infected with hepatitis B as adults recover fully, even if their signs and symptoms are severe. Infants and children are much more likely to develop a chronic hepatitis B infection. Although no cure exists for hepatitis B, a vaccine can prevent the disease. HEPATITIS B VIRUS: Hepatitis B virus is a hepadna virus – 'hepa' from hepatotrophic (attracted to the liver) and 'dna' because it is a DNA virus and it has a circular genome composed of partially double-stranded DNA. The viruses replicate through an RNA intermediate form by reverse transcription and in this respect they are similar to retroviruses. Although replication takes place in the liver, the virus spreads to the blood where virus-specific proteins and their corresponding antibodies are found in infected people. Blood test for these proteins and antibodies are used to diagnose the infection. It has long incubation period i.e. 30 to 180 days. Virus does not kill hepatocytes but the infected cells die itself as a result of immune system attack after recognition of viral antigen on cell surface.