Epidemiological studies on hepatitis C virus infection: detection, prevalence, exposure and prevention.

Highly sensitive and specific tests for HCV infection are now available for epidemiological studies. These include: (1) the second-generation ELISA or agglutination technique with supplemental testing; (2) serotyping of antibody; (3) detection of HCV-RNA by RT-nested double PCR with the 5' noncoding region for the highest sensitivity; (4) quantitation of HCV-RNA; (5) genotyping using specific primers in the core region, and (6) sequence analysis of E2/NS1 hypervariable region 1 to identify homology among HCV isolates. Transmission of HCV is commonly done by percutaneous routes, although the route in a significant proportion of sporadic infections is unknown. Sexual transmission and perinatal transmission appear to be relatively infrequent.