Distribution of HCV genotypes among different exposure categories in Brazil

Abstract

Hepatitis C virus (HCV) infection is widespread and responsible for more than 60% of chronic hepatitis cases. HCV presents a genetic variability which has led to viral classification into at least 6 genotypes and a series of subtypes. These variants present characteristic geographical distribution, but their association with different responses to treatment with interferon and severity of disease still remains controversial. The aim of this study was to investigate the patterns of distribution of HCV genotypes among different exposure categories in Brazil. Two hundred and fifty anti-HCV positive samples were submitted to HCV-RNA detection by RT-PCR and their genotype was determined by restriction fragment length polymorphism (RFLP) analysis. In addition, the genotype/subtype of 60 samples was also determined by a reverse hybridization assay. HCV 1 was the most prevalent (72.0%), followed by type 3 (25.3%), HCV 2 (2.0%) and HCV 4 (0.7%). The HCV genotype distribution varied among the different exposure categories, with HCV 1 being more frequent among blood donors, hemophiliacs and hemodialysis patients. A high frequency of HCV 3 was observed in cirrhotic patients, blood donors from the South of Brazil and injecting drug users (IDUs). The general distribution of the HCV genotype in Brazil is similar to that in other regions of the world.

Trends in HCV prevalence, risk factors and distribution of viral genotypes in injecting drug users: findings from two cross-sectional studies

“…High frequencies of subtypes 1a and 3a are commonly found in IDUs compared to other exposure categories [3,20]. The distribution of HCV genotypes found in the present study corroborates these findings.…”

“…Moreover, viral genotypes have been associated with different routes of transmission [20]. Recently, a changing pattern of HCV genotype distribution has been described in Europe, with increasing frequencies of HCV 1a, 3a and 4 infections (the latter especially in IDUs) [3].…”

Association of hepatitis C virus NS5B variants with resistance to new antiviral drugs among untreated patients

“…Genotypes 2 and 3 are also often observed in this population, but genotypes 4 and 5 are more rare (Campiotto et al 2005). Therefore, it was interesting to find two samples of genotype 4 in our study population, as it was previously described as a rare genotype in rJ (Oliveira et al 1999). The sequence fragment analysed in this study encompassed NS5B codons 228-336, including enzyme motifs B and C. Three major domains constitute the structure of the rNA-dependent rNA polymerase, NS5B: fingers, palm and thumb (ranjith- Kumar & Kao 2006).…”

Serological, epidemiological and molecular aspects of hepatitis C virus infection in a population from Londrina, PR, Brazil, 2001-2002

“…These results are in agreement with the literature, with genotype 1 being the most common HCV genotype in North and South America, Europe and Asia 27 . In a previous study carried out in a Brazilian population consisting of different HCV exposure categories, genotype 1 was detected in 72% of the subjects, type 2 in 2%, type 3 in 25.3%, and type 4 in 0.7% 21 . Differences in the distribution profile of the HCV subtypes in the different geographical regions of Brazil have been reported, with subtype 1b being the most prevalent in the southeast area followed by subtype 1a, subtypes 1b and 3a being the most frequent in the northeast area, and subtype 1a being the most common in the center-west region, followed by subtype 3a 18 .…”

“…Prevalence is lower in populations highly selected by previous screening for risk factors associated with the infection, such as blood donors, and is higher among groups highly exposed to parenteral transmission of the virus, such as intravenous drug users or hemodialysis patients 2,13,21,29 . In Brazil, available data usually refer to large centers 8,12,22 .…”