Types of Viral Hepatitis and Its Etiology - Essay Example

HEPATITIS Hepatitis is an injury found in the liver characterised by presence of inflammatory cells in the liver tissue. The word hepatitis came from the Greek word hepato- meaning ' liver' and -itis meaning 'inflammation'. This condition can be self limiting which means healing on its own or can progress to scarring of liver. Hepatitis is categorized as acute or chronic hepatitis. Acute hepatitis is when it lasts less then 6 months and chronic hepatitis is when it persists longer than 6 months ("Hepatitis"). The most common causes of viral hepatitis are the hepatitis A, hepatitis B and hepatitis C viruses (Frymoyer). This group of viruses known as the hepatitis viruses are responsible to most liver damages worldwide ("Hepatitis"). This paper discuss the three types of viral hepatitis focusing on the etiology or the cause of the disease, epidemiology, signs and symptoms, diagnosis, mode of transmission, persons at risk, prevention and treatment of hepatitis. HEPATITIS A Etiology In children, the most common form of hepatitis is hepatitis A also known as infectious hepatitis. This form is caused by the hepatitis A virus (HAV) or picornavirus, an enteric ("Hepatitis", PHAC a) non-enveloped virus came from Picornoviridae family, which lives in the stools of infected individuals (Gavin). Epidemiology Hepatitis A accounts for up to 35% of all cases of acute viral hepatitis in developed countries (Stellato). Outbreaks are usually traced to poor sanitary conditions such as failing to wash hands after toilet breaks. ("Hepatitis A", Frymoyer). In underdeveloped countries, hepatitis A virus (HAV) is endemic, and nearly 90% of these adults demonstrate immunity to HAV from childhood exposure (Stellato). Signs and Symptoms Hepatitis A has an incubation period of 10 to 50 days. This is the time from the exposure to the HAV until the onset of the disease. The duration of the disease is typically two to three weeks, but it can last up to one to two months (Main a). The signs and symptoms of hepatitis A may range from mild to severe. These may include an abrupt onset of fever, malaise, loss of appetite, nausea, stomach pain, dark-colored urine and jaundice (Sandeep, New York State Department of Health a). Infected people excrete the HAV with their stool two weeks before and one week after the appearance of jaundice ("Hepatitis"). The disease is rarely fatal and most people recover in a few weeks without any complications. Adults have signs and symptoms of illness more often than children. Infants and young children tend to have very mild symptoms and are less likely to develop jaundice than are older children and adults. Not everyone who is infected will have all of the symptoms (New York State Department of Health a). The symptoms commonly appear within 28 days of exposure, with a range of 15-50 days, (New York State Department of Health a) and approximately 15% of sufferers may experience relapsing symptoms from six months to a year following initial diagnosis ("Hepatitis"). Diagnosis Hepatitis A is diagnosed by finding IgM-class anti-HAV in serum collected during the acute phase of disease (FDA). After several months, the IgM anti-HAV titer decreases, while the IgG anti-HAV rises and persists indefinitely (Linnen, Stellato). This is demonstrated by the patient's immune system that makes antibodies against hepatitis A confer immunity against future infection. This explains why Hepatitis A appears as an acute form of hepatitis and does not have a chronic stage ("Hepatitis A"). Mode of Transmission Hepatitis A virus is usually spread from person to person by putting something in the mouth that has been contaminated with the stool of a person with hepatitis A (New York State Department of Health a). This type of transmission is called the "fecal-oral" route ("Hepatitis"). This route is demonstrated when a person with hepatitis A prepares food after using the bathroom and touched the food rendering it contaminated with HAV (NWHIC). For this reason, the virus is more easily spread in areas where poor sanitary condition is present or good personal hygiene is not observed. The contagious period begins about two weeks before symptoms appear and lasts about one week after symptoms appear (New York State Department of Health a). Another mode of transmission is through personal contact with a household member or sex partner who has hepatitis A ("Hepatitis"). Waterborne outbreaks are infrequent and usually associated with sewage-contaminated or inadequately treated water. Studies shows that casual contact does not spread the hepatitis A virus (New York State Department of Health a). Persons at Risk People who have high risk of infection include children and adults living in areas with increased rates of hepatitis, people working in food industries exposed to contaminated food or water, persons traveling to countries such as Central and South America, Africa, the Middle East, Asia, and the Western Pacific where hepatitis A is common, men who have sex with men, injecting and non-injecting drug users, sexual contacts or household contacts of infected persons and inmates in prisons (New York State Department of Health a). Moreover, individuals with long-term liver disease may be at higher risk for a more serious hepatitis infection (PHAC a). Prevention Hepatitis A can be prevented by good hygiene and sanitation ("Hepatitis"). To prevent person-to-person spread it is recommended to exercise careful hand washing after using the bathroom, changing diapers and before preparing or eating food (New York State Department of Health a). Avoidance of raw foods and drinking tap contaminated water also help prevent and reduce spread of infection ("Hepatitis"). For long-term protection, hepatitis A vaccine is best. The Hepatitis A vaccine protects against the virus in more than 95% of cases for ten years. The vaccine contains inactivated Hepatitis A virus providing active immunity against a future infection ("Hepatitis A"). According to the latest FDA update, vaccine is now approved for children as young as 12 months of age (New York State Department of Health a). For close contacts of a person with HAV infection, immune globulin (IG) shots are recommended to minimize the risk of disease. Immune globulin for hepatitis A virus protection is only effective if given within 2 weeks of the last contact with a person that is contagious. When given within 2 weeks of exposure, IG prevents clinical illness in more than 85% of recipients (New York State Department of Health a, Frymoyer). Treatment There is no effective medical treatment to date with Hepatitis A (PHAC a). People with hepatitis A are advised to rest, stay hydrated and avoid alcohol ("Hepatitis"). People usually recover from symptoms in 4 to 6 weeks (PHAC a). HEPATITIS B Etiology Hepatitis B also known as serum hepatitis is caused by the Hepatitis B virus (HBV), a member of the Hepadnavirus family which causes viral hepatitis ("Hepatitis B"). This virus can cause both acute and chronic form of hepatitis (Frymoyer). Epidemiology Worldwide, the prevalence of hepatitis B virus infection is highest in developing countries and lowest in developed nations. Inhabitants of Southeast Asia, China, Philippines, Indonesia, Middle East, Africa, Amazon basin, Pacific Islands and the Arctic have more than a 60 percent prevalence of serologic markers of previous hepatitis B infection, with chronic disease present in 8 to 15 percent of the population (Frymoyer, Margolis). On the other hand, inhabitants of North America, Western Europe, Australia, New Zealand and southern South America have a low prevalence of less than 20 percent (Frymoyer, Margolis). Signs and Symptoms The incubation period of HBV is two to six months. Early symptoms include poor appetite, lack of interest in food, nausea, aching muscles and joints, and mild fever. Later symptoms include yellowing of the skin, mucous membranes, and white portions of the eyes; light-coloured stools; and dark urine (Main b). HBV may either be acute (self-limited) or chronic (long-standing). Persons with self-limited infection clear the infection spontaneously within weeks to months ("Hepatitis B"). The presentation of acute disease ranges from asymptomatic to fulminant hepatitis with massive liver necrosis. The risk of chronic hepatitis after infection with HBV decreases with age. Hepatitis B infection becomes chronic in about 90 percent of neonates, 23 to 46 percent of preschoolers and 3 to 10 percent of adults (Frymoyer, West). Diagnosis The diagnosis is made through blood sample which will demonstrate antibodies against viral antigens or hepatitis B components in the patient's blood. The blood sample can demonstrate the presence of viral components called hepatitis B surface antigen (HBsAg) (Main b). The HBsAg is the first detectable viral antigen to appear during infection with this virus. When HBsAg is present, the infectiousness of the disease is at its highest level causing patients to have increased risk of developing complications ("Hepatitis B"). Shortly after the appearance of the HBsAg, another antigen named as the hepatitis B e antigen (HBeAg) will appear. Presence of HBeAg in a host's serum is associated with much higher rates of viral replication ("Hepatitis B"). More recently, PCR tests have been developed to detect and measure the amount of viral nucleic acid in clinical specimens. These tests are useful to assess a person's infection status and to monitor treatment ("Hepatitis B"). Mode of Transmission Hepatitis B is largely transmitted through exposure to bodily fluids containing the virus ("Hepatitis B"). HBV can be found in the blood and, to a lesser extent, saliva, semen and other body fluids of an infected person (New York State Department of Health b). HBV can occur from sexual contacts with an infected person, from vertical transmission or an infected mother to her baby during childbirth, or through sharing needles with an infected person (NWHIC). Hepatitis B virus is not spread by casual contact (New York State Department of Health b). Persons at Risk People that have high risk of infection include drug users who share needles; certain health care workers who have contact with infected blood; men who have sex with men, particularly those with multiple partners; people in custodial care; hemodialysis patients; certain household contacts; infants born to mothers who are hepatitis B carriers (New York State Department of Health b).; and people from countries where the virus is regularly found such as Africa, Southeast Asia, Middle East, Southern and Western Pacific Islands, Amazon Basin, Haiti and Dominican republic (PHAC b). Prevention Several vaccines have been developed for the prevention of hepatitis B virus infection ("Hepatitis B"). The Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention recommends routine vaccination of all infants, HBsAg screening in pregnant women to prevent perinatal transmission, identify household contacts who should be vaccinated and vaccination of high risk adolescents and adults ("Hepatitis B Virus", Peter). In many areas, vaccination against hepatitis B is also required for all health-care workers. Some college campus requires proof of vaccination as a prerequisite ("Hepatitis B"). Post-exposure prophylaxis is also recommended (Frymoyer, "Protection Against Viral Hepatitis"). Other means of prevention is to eliminate risky behaviors such as unprotected sex and injecting drugs, sharing of personal items such as toothbrushes and razors, tattooing and body piercing are also possible transmission pathways so careful thought of the person performing these procedures is recommended (PHAC b). Treatment There is no specific medical treatment for acute type B hepatitis (Main b). For chronic hepatitis B, there are six FDA-approved treatment options available namely alpha-interferon, pegylated interferon adefovir, entecavir, telbivudine and lamivudine. About 45% of persons on treatment achieve a sustained response ("Hepatitis", "Hepatitis B"). HEPATITIS C Etiology Hepatitis C that were once known as "non-A non-B hepatitis" is caused by a Flavivirus or hepatitic C virus (HCV) ("Hepatitis") which is found in the blood of persons who have this disease (New York State Department of Health c). Hepatitis C virus has been shown to be the causative agent of more than 90 percent of cases of non-A, non-B hepatitis associated with transfusion, intravenous drug abuse or other percutaneous exposures (Garcia, Frynomyer). In the 1960s, many "flower children" that practiced free love and abundant intravenous drug usage are now being diagnosed with HCV (Stellato). Epidemiology Hepatitis C infects an estimated 170 million people worldwide and 4 million in the United States. Co-infection with HIV is common and rates among HIV positive populations are higher. 10,000-20,000 deaths a year in the United States are from HCV; expectations are that this mortality rate will increase, as those who were infected by transfusion before HCV testing become apparent ("Hepatitis C"). Signs and Symptoms The incubation period is one to six months. Early symptoms include poor appetite, lack of interest in food, nausea, aching muscles and joints, and light fever. Later symptoms include yellowing of skin, mucous membranes, and white portions of the eyes; light-coloured stools; and dark urine. Once the late symptoms have developed, in most cases the patient quickly begins to get better. The disease typically lasts two to eight weeks (Main c). Hepatitis C may lead to a chronic form of hepatitis, culminating in cirrhosis. It can remain asymptomatic for 10-20 years. Patients with hepatitis C are prone to severe hepatitis if they contract either hepatitis A or B, so all hepatitis C patients should be immunized against hepatitis A and hepatitis B ("Hepatitis"). Diagnosis Current serologic testing techniques for identifying hepatitis C virus are rudimentary compared with those available for hepatitis B virus detection. A second-generation test that employs a recombinant immunoblot assay is more specific than the first-generation enzyme-linked immunosorbent assay (ELISA). It is anticipated that polymerase chain reactions and other newer techniques will enhance diagnostic capabilities (Bisceglie). Mode of Transmission The hepatitis C virus (HCV) is transmitted by blood-to-blood contact. In developed countries, it is estimated that 90% of persons with chronic HCV infection were infected through transfusion of unscreened blood or blood products or via injecting drug use. In developing countries, the primary sources of HCV infection are unsterilized injection equipment and infusion of inadequately screened blood and blood products ("Hepatitis C", Wright). In addition, perinatal transmission from infected mother to neonate has been demonstrated, but the risk is thought to be much lower than the risk of perinatal transmission of hepatitis B virus (Frymoyer). Recent data suggest transmission of HCV by breast feeding. Patients who have acquired HCV infection by sexual and household contact show a higher seropositive rate than the general population, as do patients receiving hemodialysis (Stellato). The risk of sexual transmission appears to be low but increases when a person is infected with both HIV and hepatitis C virus (Frymoyer). Persons at Risk Persons at highest risk for HCV infection include persons who ever injected illegal drugs, people who had blood transfusions, blood products, or organ donations before June, 1992, when sensitive tests for HCV were introduced for blood screening, and persons who received clotting factors made before 1987 (New York State Department of Health c). Other persons at risk for hepatitis C include long-term kidney dialysis patients, healthcare workers after exposures to the blood of an infected person, infants born to HCV infected mothers, people with high-risk sexual behavior or multiple partners, people who snort cocaine using shared equipment, and people who have shared toothbrushes, razors and other personal items with a family member that is HCV-infected (New York State Department of Health c). Prevention Prevention of hepatitis C infection is limited at the present time to screening blood for hepatitis C virus antibody. No vaccine is available for preexposure use, and the benefits of human immune globulin for postexposure prophylaxis are equivocal (Padilla). The CDC recommends barrier contraceptives for infected patients with multiple partners, but not for couples in a stable, monogamous sexual partnership (Frymoyer). Treatment There are no special medicines or antibiotics that can be used to treat people with the acute form of hepatitis C. The current treatment of choice is combination therapy using pegylated interferon and ribavirin (NWHIC). Interferon and pegylated interferon can be taken alone or in combination with ribavirin but the combination is currently the treatment of choice. Hence, it is important to know that treating hepatitis C is complex and is best to be handled by experienced physician in treating the disease (New York State Department of Health c). Understanding the three types of hepatitis virus - hepatitis A, hepatitis B, and hepatitis c, the characteristic to humans help determine the type of hepatitis present, route of transmission, how each virus affect the overall condition of the patient and the corresponding prevention and treatment to battle the disease. The study of hepatitis helps to deal and manage this condition as a whole. References Befeler, AS et al. Hepatitis B. Infect Dis Clin North Am 2000;14:617-32. Bisceglie, AM. "Serologic tests for hepatitis C." Liver Update Function Dis 1992;6:2-3. "Bloodborne Pathogens Section." Blood Safety Surveillance and Health Care Acquired Infections Division, Health Canada. 2003 Centers for Disease Control and Prevention. "Hepatitis A outbreak associated with green onions at a restaurant-Monaca, Pennsylvania." MMWR Morb Mortal Wkly Rep 2003;52:1155-7 "Hepatitis." en.wikipedia.org. 25 April 2007. "Hepatitis A." en.wikipedia.org. 25 April 2007. 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