HEPATITIS-C VIRUS GENOTYPES IN AUSTRALIA

The relative distribution of Australian hepatitis C virus (HCV) genoty pes was determined for 500 isolates. Genotyping was performed using a commercial reverse phase hybridization assay after amplification of th e 5' untranslated region of HCV by the polymerase chain reaction. Aust ralian isolates comprised, predominantly, genotype 1 (55%) and genotyp e 3 (38%) with genotype 2 accounting for only 7%, Genotype 3a was the most common subtype, When the major risk groups of injecting drug user s or transfusion-acquired hepatitis C were compared, there was a signi ficantly higher incidence of genotype 1b in the transfusion-acquired g roup (P < 0.03). When the age of the patients was analysed, genotype 3 a was more prevalent in the 21-40-year age group than the 41-60-year a ge group (P < 0.05). There was no significant difference in genotype d istribution between males and females. HCV genotypes 1, 2 and 3 are mo st often found in developed countries but the relatively high prevalen ce of genotype 3a in Australia is unusual.