HCV genotypes distribution in patients from Botucatu, Bauru and Assis, Sao Paulo State, Brazil

Hepatitis C is an infectious disease with variable clinical evolution, generally slow and progressive, caused by a RNA virus termed HCV (hepatitis C virus). This virus presents a structure composed by an external envelop, protein core, and a single strand RNA with approximately 9,5 Kb. RNA virus usually present a high mutation level resulting in diverse genomic sequences, and owing to these various genotypes and subtypes are evolved. HCV genotypes 1, 2 and 3 have been worldwide disseminated, being types 4 and 5 specially in Africa, and type 6 has been found in Asia. In Brazil the mostly frequent genotypes are 1, 2, and 3. The present study evaluated 1.018 plasma samples anti-HCV positive on ELISA assay, and HCV RNA positive by means of RT-PCR (Roche registered ). These plasma samples were sent from following cities of Sao Paulo state: Botucatu (N=508), Bauru (N= 415), and Assis (N= 95). Genotyping was performed by means of LiPA (Line probe assay - Bayer) which allows to analyze six HCV genotypes, and the most common subtypes. HCV genotypes regional distribution was 62.9% of genotype 1, and 34.5% of genotype 3. Genotype 2 was found in Botucatu and Bauru regions only in a frequency of 2.1%, and genotype 5 was shown in Botucatu (0.2%) only. HCV subtypes distribution was as follow: in Botucatu region - subtype 1a (25%), 1b (29.3%), 1a/1b (3.5%), 2b (0.6%), 3a (35.0%), 5a (0.2%); in Bauru region-subtypes 1a(31.1%), 1b (27.2%), 1a/1b (2.4%), 2b (1.9%), 2a/2c (0.2%), 3a (32.3%); in Assis region - subtypes 1a (26.3%), 1b (26.3%), 1a/1b (2.1%), 3a (41.1%). The used genotyping technique did not allow to perform the subtypes characterization in 4.1% of samples. The HCV genotypes distribution in these Sao Paulo state regions was similar to those observed in other Brazilian and world sites, although some regional differences on HCV subtypes were observed, such as the occurrence of African genotypes (5 and 5a) in Botucatu region.