Absence of detectable hepatitis B antigen (HBAg) in the commercial oyster, Crassostrea gigas Thunberg, in Hong Kong

Abstract

The locally grown commercial oyster in Hong Kong, Crassostrea gigas Thunberg, is faecally polluted particularly in the summer months at a time when oyster consumption and the incidence of viral hepatitis similarly increase. Whole oysters and isolates of tissues including the digestive diverticula and mantle fluids, in unconcentrated or concentrated forms were examined by counterimmunoelectrophoresis for the presence of the hepatitis-B antigen (HBAg); No antigen was detected in samples examined on a monthly basis over a one year period nor those examined hourly for one day in mid-summer. HBAg may not have been detected since the pollution of the oyster beds was considered to be predominantly of animal rather than human origin.