Hepatitis Virus

Primary members HAV HBV HCV HDV HEV

Hepatitis A Virus (HAV) Picornaviridae Hepatovirus fecal-oral transmission

Biological Properties Size and Shape –27nm –spherical –+ssRNA –no envelope –icosahedral –only one serotype

Biological Properties Cultivation –animal inoculation: primates –cell cultivation: NO CPE Resistance: Strong –resistance: low pH, organic solvents and detergents, heat, water –Sensitivity: chloride

Pathogenicity Source: humans Transmission: the oral-fecal route Pathogenesis –little impairment to gut –mainly replicate in liver

Pathogenicity Clinical findings: acute, rarely chronic –Asymptomatic –Acute hepatitis A Results – recovery –fulminant hepatitis

Immunity Anti-HAV IgM Anti-HAV IgG

Microbiological Diagnosis anti-HAV IgM: early infection anti-HAV IgG: prior infection or vaccination

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

Prevention and Treatment Prevention –general rules: Improved hygiene –Special measures: effective killed vaccines Treatment –no –Supportive care –immune globulin

Hepatitis B Virus (HBV) Hepadnavirus family DNA genome special replication Multiple clinical findings

Biological Properties Size and Shape –40nm –enveloped –partly double stranded, circle DNA –3.2 kb

Biological Properties Structure –large spherical particle or Dane particle an intact, mature, and infectious HBV virion Composition –small spherical particle –tubular particle

Biological Properties genetic and antigenic compositions –S region HBsAg, PreS2 Ag, PreS1 Ag –C region HBeAg, HbcAg –P region DNA polymerase, retrotranscriptase, and RNase H –X region HBxAg

( ( ( ccc-DNA Covalently closed circular RNA Precore, L, M, S + X proteins Capsid protein P protein Reverse transcription Golgi RNA pregenome cap 

Biological Properties Replication Cultivation – No Resistance: strong –Resistance: organic solvent, low pH, Low temperature, drying, UV, 70% alcohol –Sensitivity: autoclaving, chloride

Pathogenicity Source: human Transmission –Blood transmission –Maternal-infant transmission –Sexual contact –Close contact

Pathogenicity Pathogenesis –immune-mediated –type Ⅱ hypersensitivity –type Ⅲ hypersensitivity –type Ⅳ hypersensitivity –

Pathogenicity Clinical Findings –Clinical types: acute, chronic, severe hepatitis, hepatocirrhosis, chronic carrier –Carcinogenesis: hepatocellular carcinoma

Carcinogenesis The evidence –Hepatoma incidence in hepatitis B patients is higher than that in non- hepatitis B patients. –The possibility of detection of HBV infection in hepatoma patients is higher than that of normal people. –Integrated HBV DNA (X region) can be found in hepatocyte nucleus of hepatoma. –Animal hepatitis viruses can induce hepatoma in animals, and integrated viral DNA can also be found in hepatocyte nucleus.

Carcinogenesis The related mechanisms –toxic materials –enhanced multiplication of liver cell –HBxAg

Immunity CMI HI –HBsAg –Anti-HBs

Antigen-Antibody detection Members –HBsAg, anti-HBs –HBeAg, anti-HBe –anti-HBc IgM / IgG

Antigen-Antibody detection Screen blood donor Help diagnose hepatitis B Help judge the prognosis and outcome Investigate epidemiology of hepatitis B and detect chronic carriers or asymptomatic carriers. Judge people’s immunity level and effect of vaccination.

Interpretation of antigen and antibody HBsAg –the presence of HBV infection anti-HBs –previous HBV vaccination or previous infection which has recovered –the individual obtains protection against re- infection.

Interpretation of antigen and antibody HBeAg –the multiplication of HBV virion –the patient serum is highly infectious –Persistent high titer indicates chronic conversion anti-HBe –patient is recovering and get some immunity to HBV

Interpretation of antigen and antibody anti-HBc IgM –acute hepatitis B or a recent HBV infection in which replication of virion presents anti-HBc IgG –previous HBV infection or chronic HBV infection

Interpretation of antigen and antibody The HBV Panel - Interpretation

Prevention and Treatment Prevention –General measures –Active immunity: subunit vaccine –Passive immunity: Anti-HBV immune globulin Treatment –Supportive care: major

Hepatitis C Virus (HCV) Flaviviridae Biological Properties –30 to 60nm –Icosahedral –+ssRNA –envelope – high variation: HCV quasispecies

Pathogenicity source: patients transmission: blood Clinical findings –Acute –Chronic –Cirrhosis –hepatocellular carcinoma

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