Molecular Epidemiology of HCV Genotypes among Injection Drug Users in Taiwan

• Main Authors: Huang-Jie Lin, 林皇傑
• Other Authors: Shiau-Ting Hu
• Format: Others
• Language: zh-TW
• Published: 2007
• Online Access: http://ndltd.ncl.edu.tw/handle/09907255199493692194

碩士 === 國立陽明大學 === 微生物及免疫學研究所 === 95 === The numbers of injection drug users (IDUs) infected with human immunodeficiency virus type 1 (HIV-1) increased rapidly in the past few years in Taiwan. According to our previous study, the HIV epidemic among Taiwanese IDUs was mainly caused by a circulating recombinant form (CRF) 07_BC that originated from Yunnan Province of mainland China. In addition, more than 90% of Taiwanese IDUs have been infected with hepatitis C virus (HCV). Therefore, the aims of this study were 1. To study the HCV genotypes in HIV-infected IDUs in Taiwan; 2. To compare the distribution of HCV genotypes in IDUs infected with different HIV-1 subtypes; 3. To trace the origin of new HCV genotypes in Taiwan; 4. To compare different HCV genotyping assays. One hundread and eighty HCV seropositive IDUs were selected from a group of HIV-1-infected IDUs for this study. This group of IDUs consists of 150 CRF07_BC infected IDUs (50 each from northern, central, and southern Taiwan) and 30 IDUs infected with either HIV-1 CRF01_AE or subtype B type. RNA was extrated from the plasma samples and reverse transcription and polymerase chain reaction (RT-PCR) with multiplex subtype-specific primers were used for HCV genotyping. In addition, phylogenetic analyses using nucleotide sequences from HCV core, E1 or NS5B genes were also conducted to determine the HCV genotypes and subtypes. The results showed that among 168 IDUs whose plasma samples contained HCV RNA signals, the rates for single, double, triple, quadruple, penta-, hexa- and hepta-subtype infections were 26.2%, 21.4%, 29.8%, 9.5%, 4.2%, 3.6% and 0.6%, respectively. In total, 416 HCV strains of the following genotypes were found from 168 patients (2.5 strains per person): 1a (33), 1b (70), 2a (90), 2b (34), 3a (36), 3b (24), 4 (48), 5a (14), 6a (51), 6n (5), 6r (3) and recombinant (8). It was interesting that after 2002 there were an apparent rise in average rates of HCV strains infected per person. If we used the date of HIV diagnosis to analyze the distribution of different genotypes from 1995 to 2005, genotypes 4, 5a, 6a, 6n, 6r and recombinant strains did not emerged until 2002 or 2003. Phylogenetic tree analysis of HCV Core and NS5B genes demonstrated that 5 subtype 6n and 3 subtype 6r were identified and they which clustered with 6n from kunming (km42) and unassigned 6(r) (gz52557) from Guangzhou respectively. Regarding HBV infection, 20% of HIV-1-infected IDUs were co-infected with HBV. Phylogenetic analysis showed 83.3% were B subtype and 17.3% were C subtype. In conclusion, this study demonsated that the HCV genotypes among Taiwanese IDU population were very diversed and complicated, while most of the HBV infections in the same population originated from vertical transmission. Futher studies were needed to understand the impact of these coinfections to the AIDS desease progression of this cohort.