High proportion of hepatitis C virus genotypes 1 and 3 in a large cohort of patients from Southern Brazil.

Hepatitis C virus (HCV) isolates have been divided into six genotypes (1 to 6). The duration of hepatitis C standard treatment is 48 weeks for patients infected with HCV genotype 1 vs 24 weeks for those infected with genotypes 2 and 3. A total of 1544 HCV isolates from chronic patients living in the southern Brazilian states of Rio Grande do Sul (RS, n=627) and Santa Catarina (SC, n=917) were genotyped by restriction fragment length polymorphism (RFLP) of polymerase chain reaction (PCR) products. In RS, 338 (53.9%; 95% CI 50.0-57.8%), 34 (5.4%; 95% CI 3.8-7.4%) and, 255 (40.7%; 95% CI 36.9-44.6%) samples were from genotypes 1, 2, and 3, respectively. In SC, 468 (51%; 95% CI 47.8-54.2%), 26 (2.9%; 95% CI 1.9-4.1%) and, 423 (46.1%; 95% CI 42.9-49.3%) samples were from genotypes 1, 2, and 3, respectively. Genotyping results were confirmed by direct nucleotide sequencing of PCR products derived from 68 samples, without any discrepancy between PCR-RFLP and nucleotide sequencing methods. In conclusion, almost half of the hepatitis C patients from South of Brazil are infected by genotypes 2 and 3 and, these results have important consequential therapeutic implications as they can be treated for only 24 weeks, not 48.