50# Worldwide carrier rate 300 million# 1,50,000 new cases/year in U.S.# Replication defectiveFulminant hepatits 0.3-3%; 20% in pregnant women# Clinical disease: mild or asympto- matic; rare after childhood# 300,000 new infections/year in U.S.# Most important cause of transfusion related hepatitis# Dependent on HBV coinfection for multiplicationTransmission:# Fecal-oral raw shellfish (concen- trate virus)# Parental, close personal contact# Transfusion# Parenteral, close personal contactParenteral, close personal contactWaterborneYoung adults # Not shed in semen, aliva, urine# Shed in stool 2 weeks before onset of jaundice and 1 week after# Dialysis# Needle-sticks# IV-drug use# Male homosexual activity# Route of transmission undetermined in 40-50% of cases Incubation2-6 weeks4-6 weeks2-26 weeks4-7 weeks in superinfection2-8 weeksCarrier stateNone1% blood donors1%1-10% in drug addictsUnknownProgression to chronic hepatitisNone5-10% acute infections>50%">