广西地区丙型肝炎病毒的基因型分布与流行病学特征

Hepatitis C virus genotype/subtype distribution and evolution among Chinese blood donors: Revealing recent viral expansion

Hepatitis C virus (HCV) genotype (GT) distribution in China shows significant geographical and demographic difference. As a routinely tested virus in Chinese blood bank systems, rare molecular epidemiology research in blood donors is reported. Our purpose is to investigate the HCV GT/subtypes distribution, phylogenetic analysis and population genetics in Chinese blood donors. Anti-HCV screen positive samples and donor demographics were collected. HCV Core and E1 gene fragments were amplified by RT-PCR, followed by sequencing and phylogenetic analysis to determine HCV GTs/subtypes using MEGA 7.0. The population genetics were performed using Arlequin v3.0 and Beast v1.10.4. SPSS Statistics 17.0 software was used to analyze the correlation between HCV GTs/subtypes distribution and demographic characteristics. 419 and 293 samples based on Core and E1 gene respectively were successfully amplified. HCV la, lb, 2a, 3a, 3b, 6a, 6e and 6n were found, and the corresponding proportions were 0.66% (3/455), 58.68% (267/455), 17.80% (81/455) and 5.05% (23/455), 3.52% (16/455), 12.31% (56/455), 0.88% (4/455) and 0.66% (3/455). Samples from Guangxi showed the most abundant genetic diversity with 8 subtypes were found. The number of haplotypes in HCV-1b is higher than 2a and 6a. The negative Tajima's D and Fu's Fs values of HCV-1b, 2a and 6a suggested the population expansion of those HCV subtypes. The distribution of HCV GT showed significant statistical difference by age and ethnicity. Conclusion: An abundance of HCV genetic diversity was found in Chinese blood donors with mainly 1b and then 2a subtype. There were significant geographical and demographic differences in HCV GTs/subtypes among Chinese blood donors. HCV subtype 1b has stronger viability and HCV subtype 6a has experienced significant expansion.

Hepatitis C Virus in mainland China with an emphasis on genotype and subtype distribution

Due to the low fidelity of the RNA-dependent RNA polymerase, Hepatitis C virus (HCV) mutates quite frequently. There are seven genetically divergent genotypes (GTs) distributed in the world, each of which contains several closely related subtypes. The peer-reviewed literatures reporting the prevalence rate of HCV GTs in Chinese hospitalized patients were identified by systematic searching of three electronic databases, and the prevalence rates were pooled through 137 qualified studies. The significant difference between HCV GT and HCV viral load and severity of hepatitis were analyzed under Chi-squared or Fisher's exact test. Data from epidemiological studies on hospitalized patients demonstrated that HCV GTs 1-6 have been found in China, of which 1b (62.78%(95% CI: 59.54-66.02%)) and 2a (17.39% (95% CI: 15.67-19.11%)) are the two predominant subtypes. HCV GTs and subtypes exhibits significant regional divergence. In North, Northwest, Northeast, East (except Jiangxi province) and Central China (except Hunan province), HCV-1b, 2a remain the two predominant subtypes; South China shows the most abundant genetic diversity that 14 subtypes were found, and HCV-3 in the Southwest China remains higher prevalent subtype than the other regions. In addition, co-infection in Liaoning province of Northeast China is the most diverse with 10 co-infection types, and Tibet has the highest rate of co-infection. The associations between HCV GTs and patients group, severity of illness and antiviral treatment efficacy were also discussed in this review.

Assessment of HCV genotypes in Yunnan Province of Southwest China

Recently, we reported that the frequency of hepatitis C virus (HCV) genotypes and subtypes has rapidly changed among intravenous drug users (IDUs) in Yunnan Province over the last 5 years; this is especially true for subtype 6a which has increased in frequency from 5 to 15%. Here, we assessed 120 HCV-positive plasma samples from the general population (GP). HCV NS5B fragments were amplified and sequenced by PCR. We identified four HCV genotypes (1, 2, 3 and 6) and seven HCV subtypes (1b, 2a, 3a, 3b, 6a, 6n, and 6k) in this population. Genotype 3 was predominant, with a distribution frequency of 0.484, followed by genotype 1 (0.283), genotype 6 (0.133) and genotype 2 (0.100). HCV subtypes 3b (frequency 0.292) and 1b (frequency 0.283) were the most common subtypes. A comparison of the current data with previous results reported for IDUs showed that the distribution frequencies of genotypes 1, 2 and 6 were significantly different between patients in the GP and IDUs (P < 0.05). Among the HCV subtypes, the distribution frequencies of 1b, 2a, 6a, and 6n were significantly different between patients in the GP and IDU groups (P < 0.05). Moreover, Phylogenetic analyses showed that HCV subtype 6a strains isolated from IDUs and the GP were intermixed and not separately clustered. HCV subtype 6a was predominant not only among IDUs but also among those in the GP in the Guangdong Province and Vietnam. However, HCV subtype 6a was predominant only among IDUs and not among those in the GP in the Yunnan and Guangxi Provinces. Our results indicate that the HCV subtype 6a could rapidly spread across China.