INFLAMMATON OF THE LIVER

Hepatitis A-B Viruses part І Dr. Osama AL Jiffri

HEPATITIS A VIRUS

HEPATITIS VIRUS Hepatitis A-B-D-C-F-E Hepatitis A and E Viruses do not persist in the liver There is no evidence of progression to chronic liver damage Hepatitis B, D, C, may be associated with persistent infection and progression to chronic liver disease

Hepatitis A Virus: Structure and Classification  Picornavirus  genus : Hepatovirus  Member of the Enterovidae  Offcially referred to as enterovirus 72 The virions have cubic symmetry and are 27nm Naked icosahedral capsid SS RNA (7400 nucleotides) Single serotype worldwide Humans only reservoir

Hepatitis A Structure

Fecal-oral transmission Mode: Close personal contact (e.g., household contact, sex contact, child day-care centers) Contaminated food, water (e.g., infected food handlers, contaminated raw oysters) HEPATITIS A VIRUS TRANSMISSION

GEOGRAPHIC DISTRIBUTION OF HEPATITIS A VIRUS INFECTION

Hepatitis A: Pathogenesis Incubation 4 weeks (range 2-6 weeks) Particularly in young children Replicates in hepatocytes (little damage to cells) released via bile to intestines 7-10 days prior to clinical symptoms

Hepatitis A: Clinical Features-1 –An acute illness with: Clinical illness usually starts with a few days of malaise, loss of appetite, fatigue, abdominal pain, nausea, vomiting) jaundice or elevated serum aminotransferase (AST, ALT) levels, dark urine, light stool Adults usually more symptomatic Patients are infective while they are shedding the virus in the stool- usually before the onset of symptoms Complete recovery 99% (rarely can be fulminant)

Week Response Clinical illness ALT IgM IgG HAV in stool Infection Viremia EVENTS IN HEPATITIS A VIRUS INFECTION

Hepatitis A Diagnosis Detection of anti HAV IgM antibody by an ELISA or Radioimmunoassay test Liver enzyme test

PREVENTING HEPATITIS A Hygiene (e.g., hand washing) Sanitation (e.g., clean water sources) Immune globulin (pre- and post-exposure) (older passive vaccination) Hepatitis A vaccine (pre-exposure)

Hepatitis A Treatment Supportive- no specific role of antiviral therapy Lifelong immunity likely after infection or vaccination

HEPATITIS A VACCINES 1 st dose at time 0 2 nd dose 6-12 months afterwards

Hepatitis A Vaccine Vaccine is recommended for the following persons 2 years of age and older: –Travelers to areas with increased rates of hepatitis A - Persons with chronic liver disease –Children living in areas with increased rates of hepatitis A

Hep A : Passive Immunization Hepatitis A immune globulin can be given up to 2 weeks after an exposure Immunity temporary (4-5 months) Also given in travelers leaving for endemic area on short notice (ie not enough time for the vaccine to be effective)

Hepatitis B Virus

HBV: Structure Family : Hepadnaviridae (Hepatitis DNA viruses) complete virion 42nm enveloped virus and double-shelled Dane particle (consist only of excess surface antigen) Hepatitis B core antigen (HBcAg) Hepatitis B e antigen (HBeAg) Genome consists Circular double stranded DNA Length of 3200 nucleotides Virus stable and resist environmental factors

CDC and HI Vand Hepatitis.com, 2002 HBV: Epidemiology Worldwide Distribution Acute and Chronic infections 1. Center for Disease Control

Geographic Distribution of Chronic HBV Infection HBsAg Prevalence  8% - High 2-7% - Intermediate <2% - Low

Sexual Parenteral Perinatal Hepatitis B Virus Modes of Transmission

Hepatitis B Virus in Various Body Fluids HighModerate Low bloodsemenurine serumvaginal fluidfeces wound exudatessalivasweat tears breast milk

Risk Factors for Acute Hepatitis B Heterosexual* (41%) Homosexual Activity (9%) Household Contact (2%) Health Care Employment (1%) Other (1%) Unknown (31%) Injecting Drug Use (15%)

HBV Pathogenesis Virus enters hepatocytes via blood Immune response (cytotoxic T cell) responsible for clinical syndrome 5 % of adults become chronic carriers (HBsAg> 6 months) Higher rate of hepatocellular carcinoma in chronic carriers, Hepatitis B surface antibody likely confers lifelong immunity Hepatitis B e Ag indicates high transmissibility Hepatitis B e Ab indicates low transmissibility

Hepatitis B - Clinical Features Incubation period: Average days Clinical illness (jaundice):less common in young children Acute case-fatality rate:0.5%-1% Chronic infection: <5 yrs, 30%-90%  5 yrs, 2%-10% ( More likely in asymptomatic infections) 15 to 25% of chronically infected patients will die from chronic liver disease

Outcome of Hepatitis B Virus Infection by Age at Infection Symptomatic Infection Chronic Infection Age at Infection Chronic Infection (%) Symptomatic Infection (%) Birth 1-6 months7-12 months 1-4 years Older Children and Adults

Possible Outcomes of HBV Infection Acute hepatitis B infection Chronic HBV infection 3-5% of adult-acquired infections 95% of infant- acquired infections Cirrhosis Chronic hepatitis 12-25% in 5 years Liver failure Hepatocellular carcinoma 6-15% in 5 years 20-23% in 5 years Death

Acute Hepatitis B Virus Infection with Recovery Typical Serologic Course Weeks after Exposure Titer Symptoms HBeAg anti-HBe Total anti-HBc IgM anti-HBc anti-HBs HBsAg

Progression to Chronic Hepatitis B Virus Infection Typical Serologic Course Weeks after Exposure Titer IgM anti-HBc Total anti- HBc HBsAg Acute (6 months) HBeAg Chronic (Years) anti-HBe Years

Current Treatment Options for HBV Interferon alfa (Intron A) Lamivudine (Epivir HBV) Adefovir dipivoxil (Hepsera)

Prevent perinatal HBV transmission (HBs Ag screening of pregnant women) Routine vaccination of all infants Vaccination of children, adolescents, and adults in high-risk groups Control of Hepatitis B

Hepatitis B Vaccine Infants: several options that depend on status of the mother –If mother HBsAg negative: birth, 1-2m,6-18m –If mother HBsAg positive: vaccine and Hep B immune globulin within 12 hours of birth, 1-2m, <6m Adults –0,1, 6 months Vaccine recommended in –All those aged 0-18 –Those at high risk

Hepatitis B High Risk Groups Persons with multiple sex partners or diagnosis of a sexually transmitted disease Men who have sex with men Sex contacts of infected persons Injection drug users Household contacts of chronically infected persons Infants born to infected mothers Infants/children of immigrants from areas with high rates of HBV infection Health care and public safety workers Hemodialysis patients

Hepatitis B: Passive Immunization Infants of surface antigen positive mothers Exposures to infected blood or infected body fluids in individuals who are unvaccinated, unknown vaccination, or known non-responders. –Ideally within 24 hours –Probably not effective >7days post exposure

سيرة ذاتية أخرى ● نماذج منشورات FID العنوانالوصف تاريخ الإضافة 6370 فيروسات محاضرة رقم (1) Papilloma viruses and Poxviruses 11/7/ :43:56 PM تحميل الملف 6373 فيروسات محاضرة رقم (2) Viral Agents Causing Gastroent eritis 11/7/ :53:55 PM تحميل الملف BIOSAFE TY-01 12/26/ :15:12 PM تحميل الملف BIOSAFE TY-02 12/26/ :39:23 PM تحميل الملف الملفات