To precisely investigate the distribution of Hepatitis C Virus in Korea sequencing for the 222 bp (nt: 7975-8196) of NS5B and additionally for the 76 bp of E1 was conducted. Universal primers which were expected to be able to look for any HCV type were designed. Of a total of fifty-six anti-HCV positive sera which were composed of thirty-three PCR typing-positive, eleven PCR typing-negative and ten still not typing-tried, fifty-four were RT-PCR-positive for the NS5B and of the rest two sera RT-PCR-negative for the NS5B, one was positive for the E1. Fifty-five RT-nested PCR-positive samples were directly sequenced after PCR amplification or sequenced after cloning. Based on their nucleotide sequence data, sequence homologies were analyzed with consensus sequences for all HCV types identified to date and the phylogenetic tree was constructed. Of fifty-five sequenced, type 1a, 1b, 2a, 2b, and 7a were found, 3, 24, 24, 1, and 1, respectively. Of twenty-one PCR typing-negative and still untyped, eighteen were sequenced and their distribution is the following - 1a: 1, 1b: 8, 2a: 8, and 7a: 1. One of the three 1a's seems to be a Korea-native type. Another intriguing case is the fact that type 7a which has been found only in Vietnam was also found in Korea. This is the first report that Korea-native HCV 1a and type 7a were found in Korea, although those results remain to be verified. Reverse dot blot typing was also tried and well consistent with sequencing. It revealed that two samples known as a single infection, 1a or 1b, were 1a+1b-coinfected. It remains to be further studied whether the coinfection is really true or not.
