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

Objective To determine the prevalence of hepatitis G virus (HGV) carriage in Queensland blood donors. Design Cross‐sectional survey with retrospective longitudinal study of HGV‐positive donors. Setting Brisbane Red Cross Blood Bank, 1995. Subjects 100 consecutive blood donors attending the Blood Bank on two days in October 1995 and 20 blood donors with a raised plasma alanine aminotransferase (ALT) level on their last donation. Outcome measures Presence of HGV RNA by reverse transcription polymerase chain reaction (RT‐PCR) in currently donated blood and in blood samples archived for up to 34 months. RT‐PCR used two different reverse transcription methods and three different specific sets of primers and probes. Results Five of the 120 blood donors were positive for HGV RNA by all RT‐PCR methods (four of the 100 with normal ALT levels [4%] and one of the 20 with raised ALT levels [5%]). Retrospective testing of archived samples showed that four of these five had been persistently HGV RNA‐positive for at least two years, while the fifth had been HGV RNA‐negative on two donations before becoming HGV RNA‐positive. No risk factors were identified for this donor. Conclusions A relatively large number of Queensland blood donors (4%) are persistently HGV RNA‐positive.

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The presence of hepatitis E virus-specific antibodies (anti-HEV) was determined in selected Australian groups. Anti-HEV was detected initially using a recombinant antigen-based enzyme immunoassay (EIA). It was found that 1 of 279 (0.4%) blood donors, 14 of 182 (7.7%) Indochinese refugees, 2 of 89 (2.2%) sera submitted for amoebic serology (generally people who had visited developing countries), 1 of 13 (7.7%) patients with non-A, non-B hepatitis, none of 7 (0%) patients with fulminant non-A, non-B hepatitis, and none of 33 (0%) control sera were repeatedly reactive by the HEV EIA. The positive sera were subjected to further testing using a supplemental immunoblot. Preliminary data suggest that while potentially large numbers of people infected with HEV are entering Australia, no compulsive evidence was found in these particular groups for endemic HEV infection in Australia. This is the first seroepidemiological survey of HEV in Australia.