Hepatitis Viruses Class Notes

Hepatitis Viruses Hepatitis A • Formerly known as infectious hepatitis • Improved sanitation and the hepatitis A vaccine are the most effective • Transmission • Fecal-oral route • Ingestion of contaminated food and water or through direct contact with an infectious person 1 • Diagnosis • HAV-specific IgM and IgG antibodies in the blood • RT-PCR: to detect the hepatitis A virus RNA • Treatment • No specific treatment • Maintaining comfort and adequate nutritional balance • Infection may be slow and may take several weeks or months • • Prevention • Improved sanitation, food safety and immunization • Inactivated hepatitis A vaccine • 1 or 2 doses • Nearly 100% protective 1 month after vaccination • People at increased risk: • Travelers to countries where the virus is endemic; • Men who have sex with men • People with chronic liver disease 2 Viral Hepatitis B • Identified as serum hepatitis • Symptoms begin an average of 90 days (range: 60–150 days) after exposure • Presence of signs and symptoms varies by age • Asymptomatic: <5 years and newly infected immunosuppressed adults • Symptomatic: 30%–50% of persons aged ≥5 years Clinical finding • Acute Hepatitis • Loss of appetite, nausea, vomiting, body aches, mild fever, dark urine, jaundice, Itchy skin • Illness lasts for a few weeks and then gradually improves • Fulminant Hepatitis • More severe liver disease and may die • May be entirely asymptomatic • Chronic Hepatitis • Asymptomatic or may be associated with a chronic inflammation of the liver • Cirrhosis over a period of several years • Increases the incidence of hepatocellular carcinoma (liver cancer) • Membranous glomerulonephritis (MGN) Diagnosis • Serology • Serum or blood: • Antigens • Frequently HBsAg • Antibodies 3 • PCR 4 Transmission: • Vertical transmission (such as through childbirth) • Early life horizontal transmission (bites, lesions, and sanitary habits) 5 • Adult horizontal transmission (sexual contact, intravenous drug use) Prevention • Hepatitis B vaccine • 2 type: • Plasma obtained from patients • Recombinant DNA technology • It provides protection for 85-90% of individuals, and lasts for 23 years • two, three (0,1,6 month), or four dose • Hepatitis B immune globulin (HBIG) 6 Viral Hepatitis D Prevention • HDV-HBV co-infection: • HBV vaccine or post exposure prophylaxis (Hepatitis B Immune Globulin) • Only way to prevent HBV-HDV super infection is to educate chronic HBV carriers 7 Viral Hepatitis C Transmission • Infected blood and blood products. 8 • Transfusions and the use of shared, unsterilized, or poorly sterilized needles, syringes and injection equipment or paraphernalia • Injection drug use is the most common 9 Prevention • Screen the blood supply, encourage health professionals to take precautions when handling blood and body fluids, and inform people about high-risk behaviors. • Promote needle exchange among injection drug users. • Vaccines and immunoglobulin products do not exist 10 Viral Hepatitis E Pathogenesis • Incubation period ranges from 2 weeks to 2 months. • It replicates in the cytoplasm of hepatocytes and is released into the bile and blood • Fulminant disease in pregnancy • Mortality of HEV has varied in different reports but has been as high as 1%, compared to 0.2% for hepatitis A. • Mortality of hepatitis E in pregnancy reach 20%. Epidemiology • Person-to-person spread from cases to contacts • Transmission via exposure to blood has been documented • Zoonotic transmission of HEV has been documented • Water-borne hepatitis in developing countries • the disease is more severe in pregnant women 11 • Fulminant hepatitis E causes mortality pregnant women • Clean water supply and cooking meats to a temperature that inactivates HEV • HEV inactivated at 56°C • Lack of a reliable cell culture system 12