High prevalence of infection with a single hepatitis C virus genotype in a small rural community of Argentina.

BACKGROUND: During the years preceding this study, we noticed a relatively unusual high number of individuals with elevated alanine aminotransferase (ALT) levels in O'Brien, a small rural town in Argentina. Moreover, four individuals from this town underwent liver transplantation owing to hepatitis C virus (HCV)-induced liver cirrhosis. These findings prompted us to conduct a large population-based survey to evaluate the prevalence of HCV in this community. METHODS AND RESULTS: A total of 1637 individuals were studied. The overall HCV-seroprevalence was 5.7% (93/1637), being slightly higher in men (45/769; 5.9%) than in women (48/868; 5.5%). HCV seroprevalence increased with age, reaching a peak rate of 23.9% among individuals between 61 and 70 years of age. HCV RNA was present in 82.7% of all HCV seropositive individuals identified and 100% of them were infected with genotype 1b. ALT elevations were detected in 44% of HCV+ patients and were only observed among viremic individuals. Hepatitis B virus infection was also prevalent (52%) among HCV-seropositive patients. The most common risk factor associated with HCV transmission identified was the apparent use of inadequately sterilized glass syringes by a health care provider serving the community; however, other risk factors may have also played a role in the dissemination of HCV. CONCLUSIONS: Our findings provide an explanation for the relative high number of individuals with elevated ALT levels observed in this community and form the basis of future prospective studies on the natural history of genotype 1b infection.

In vitro detection of dissimilar amounts of hepatitis C virus (HCV) subtype-specific RNA genomes in mixes prepared from sera of persons infected with a single HCV genotype.

The level of in vitro detection of viral genomes in mixes with two different hepatitis C virus (HCV) subtypes was investigated by artificially mixing previously measured subtype-specific HCV RNA genomes. The RNAs in these mixtures were reverse transcribed and then PCR amplified by using two sets of primers corresponding to the 5' untranslated region and digested with endonucleases to analyze the restriction fragment length polymorphism patterns. This approach facilitated detection of a wider range of type-specific HCV genomes than originally described, beyond equimolar concentrations of contributing HCV subtypes. Moreover, by using computerized image analysis, this study also demonstrated that the true contribution of each virus type-and consequently of mixed infections-may be underestimated when only visual observation is carried out. These results may be useful for comparing data obtained from this and other currently used methodologies.