[The distribution of hepatitis C virus genotype 1a in Yanbian area]

To investigate the distribution of Hepatitis C Virus (HCV)genotype 1a in Yanbian area, Jilin province.

The genotypes of the serum specimens of 47 patients with HCV from Yanbian area were determined by Scheme ABC of RFLP based on HCV 5' noncoding region (5'NCR). The samples of type 1a (Y2, Y4, Y6, and Y8) were amplified from the 5'NCR and NS5B regions by RT-PCR, and then sequenced directly. These sequences were subjected to phylogenetic analysis with 27 reference sequences of HCV complete genomes from GenBank.

44 specimens were HCV RNA positive, among which 19 specimens (43.2%) were of the type 1a/1b, 12 (27.3%) were of the type 1b, 8 (18.2%) were of the type 2a/1b, 4 (9.1%) were of the type 1a, and 1 (2.3%) was of the type 2a, however, the genotypes 2b and 3 approximately 6 lacked. The phylogenetic analysis for 1a samples showed that according to 5'NCR they belonged to type 1a, while on NS5B belonging to type 1b. The most nucleotide identity of 5'NCR was respectively 0.990, 0.990, 0.990, and 0.990 between Y2, Y4, Y6, Y8 and the isolate HC-J1 (genotype 1a), while that of NS5B was respectively 0.936, 0.957, 0.936, and 0.936 between Y2, Y4, Y6, Y8 and the isolate HC-J4 (genotype 1b).

In Yanbian area the distribution of HCV genotype is different from those in other areas and 1a/1b has even replaced 1b as the most HCV genotype here. The results of genotyping 1a on 5'NCR and NS5B are completely inconsistent. This phenomenon may be the consequence of recombination in evolution.