Genotype Distribution of Hepatitis C Virus in São Paulo, Brazil: Rare Subtype Found

To the Editor: Genotypes 1, 2, and 3 of the hepatitis C virus (HCV) are widely distributed throughout Western countries and the Far East ( Japan, China, Taiwan, Thailand). Types 5 and 6 are mainly confined to South Africa and Southeast Asia, respectively, in contrast to type 4, which is predominant in the Middle East and Central Africa. 1-3 To investigate the prevalence and distribution of HCV genotypes in Brazil, 348 subjects from four different populations were studied: 34 anti-HCV-positive blood donors, 23 hemophiliacs, 40 renal-transplant recipients, and 251 chronic hepatitis C (CH-C) patients. HCV genotyping was performed in serum samples of 239 (95%) out of 251 CH-C patients and of all blood-donor and hemophiliac samples by a reverse hybridization assay (Line Probe Assay -INNO-LiPA HCV or INNO-LiPA HCV II, second generation, Innogenetics, Ghent, Belgium), in which a reverse transcriptase-polymerase chain reaction (RT-PCR) product of the 5untranslated region (5UTR) is hybridized with probes from various HCV genotypes. 2 Twelve samples, of the 251 sera from the CH-C patients, and all from the renal-transplant patients were tested by a serotyping assay (HCV Serotyping Assay 1-6, Murex Diagnostics, Dartford, UK). 2 The genotyping results of the 348 HCV isolates, on the basis of the line probe and/or serotyping assays, are shown in Table Four different types were found, and their overall prevalence was 63% for type 1, 4.3% for type 2, 31.3% for type 3, and 0.3% for type 4. Four subjects revealed mixed infections: two cases within types (1a 1b in a renaltransplant recipient and 2a 2b in a CH-C patient), and two cases across types (1b 3a in a blood donor and in a CH-C patient). A similar distribution was observed for each of the four populations, as a general rule; the exceptions were genotypes 2 for the renal-transplant recipients and 3 for the hemophiliacs, whose frequencies were found to be approximately double (13%) and half (15%), respectively, their values in the other populations.