Replacement of hepatitis C virus genotype 1b by genotype 2 over a 10-year period in Venezuela

Background: Changes in hepatitis C virus (HCV) genotype distribution with time have been reported in several countries. Goals: To explore eventual changes in HCV genotype distribution in Venezuela over a 10 years period. Study: HCV genotype was determined by direct sequencing of the 5' noncoding region, in 236 isolates circulating in patients treated during years 2005 to 2006. Genotype distribution was compared with the one observed in 43 patients followed during years 1994 to 1996. Results: The prevalence HCV genotype I and 2 was 70% and 26%, respectively, in patients followed during years 1994 to 1996. The frequency of genotype 2 was significantly increased to 41 % (P = 0.04) in patients treated during years 2005 to 2006. A significant reduction in HCV genotype lb prevalence (48% to 27%, P = 0.01) was also observed after this 10 years period, whereas the prevalence of HCV genotype I a did not change over time (22% vs. 27%, NS). Transfusion was more significantly associated with infection with HCV genotype 1b than with other genotypes (52% vs. 20%, P 0.002). Conclusions: HCV subtype lb seems to have been displaced by HCV genotype 2 in a relatively short period, without increase in the frequency of genotype 3. The low frequency of HCV genotype 3 in Venezuela might be due to the fact that intravenous drug use in Venezuela is less common than in other countries. The implementation of anti-HCV testing in blood banks since 1994 in Venezuela, might have contributed to the reduction in the frequency HCV genotype lb infection.