1、 Epidemic jaundice described by Hippocrates in 5th century BC Jaundice reported among recipients of human serum and yellow fever vaccines in 1930s and 1940s Australian antigen described in 1965 Serologic tests developed in 1970sHepatitis BHepatitis B VirusHepadnaviridae family (DNA)Numerous antigeni
2、c componentsHumans are only known hostMay retain infectivity for at least 1 month at room temperature200 million carriers worldwideEstablished cause of chronic hepatitis and cirrhosisHuman carcinogen - cause of up to 80% of hepatocellular carcinomasHepatitis B Virus InfectionHBsAgHBcAgHBeAgHepatitis
3、 B VirusHepatitis B Clinical FeaturesIncubation period 6 weeks to 6 months (average 120 days)Nonspecific prodrome of fever, malaise, headache, myalgiaIllness not specific for hepatitis BAt least 50% of infections asymptomaticFulminant hepatitisHospitalizationCirrhosisHepatocellular carcinomaDeathHep
4、atitis B ComplicationsChronic Hepatitis B Virus InfectionChronic viremiaResponsible for most mortalityOverall risk 10%Higher risk with early infectionRisk of Chronic HBV Carriage by Age of InfectionHepatitis B Epidemiology Reservoir Human. Endemic Transmission BloodborneSubclinical casestransmit Com
5、municability 1-2 months beforeand after onset ofsymptomsChronic carriers Hepatitis B Perinatal Transmission* If mother positive for HBsAg and HBeAg70%-90% of infants infected90% of infected infants become chronic carriers If positive for HBsAg only20% of infants infected90% of infected infants become chronic carriers*in the absence of postexposure prophylaxis
