The Transmission Route and Selection Pressure in HCV Subtype 3a and 3b Chinese Infections: Evolutionary Kinetics and Selective Force Analysis

Prevalence and drug resistance analysis of hepatitis C virus genotypes in Heilongjiang, China

Hepatitis C still poses a threat to public safety, and there are few reports of hepatitis C virus (HCV) in Heilongjiang Province. Therefore, we aimed to study the epidemiology and resistance-associated substitutions (RASs) of HCV in Heilongjiang and explore the efficacy of treatment. 7019 specimens from Heilongjiang Province were subjected to the genotype identification. The Autoregressive Integrated Moving Average (ARIMA) model was utilized to predict HCV infection trends from 2024 to 2030. The Sanger sequencing was performed on samples of genotype(GT) 1b and 2a to investigate RASs. Phylogenetic analysis was conducted to assess the similarity of local HCV sequences with those from other countries. In addition, we tracked the effect of patients treated with DAAs and the relationship between efficacy and RASs. The predominant HCV subtypes in Heilongjiang were 1b (47.51 %) and 2a (43.85 %). From 2012 to 2023, the proportions of GT2a, GT3a, GT3b, and GT6a gradually increased. And the prevalence of GT2a will exceed that of GT1b over the next seven years. The proportion of RASs in GT1b and GT2a NS5A region was 73.47 % and 15.22 %, respectively. And the proportion of RASs in GT1b NS5B region was 100 %. Local HCV sequences exhibited phylogenetic relationships with sequences from other countries. The GT1b R30Q and GT2a C92S were correlated with drug efficacy. K107R and P206S, which have not been reported in the literature, were also related to drug efficacy. The epidemiology of HCV genotypes in Heilongjiang is becoming increasingly diverse. HCV GT1b has a large variety and a high proportion of RASs, and patients infected with this genotype of HCV need to be sequenced before treatment.

Global Origin and Spatiotemporal Spread of Hepatitis C Virus Epidemic Genotypes/Subtypes: A Complete Genome-Based Phylodynamic and Phylogeographic Analyses

Hepatitis C virus (HCV) is a pathogenic virus of global health concern. The phylodynamics of HCV genotypes/subtypes 1a, 1b, 2, and 3 are explored only for specific geographic regions. However, their genome based global origin and detailed spatiotemporal spread, have yet to be extensively studied. To study the global evolution of "epidemic" HCV genotypes/subtypes, we screened all available HCV complete genome sequences (n = 2744) from 27 countries worldwide for over four decades. We used representative sequences (n = 516) for phylodynamic and phylogeographic analyses, examining HCV worldwide origin, transmission, and spatiotemporal spread. We are the first to study the global phylogeography of genotype 2. The evolutionary rates for genotype/subtype 1a, 1b, 2, and 3 are 1.109 × 10-3, 1.096 × 10-3, 5.013 × 10-3 and 1.483 × 10-3 substitutions/site/year respectively. We deduced tMRCAs and origin location of respective HCV genotype/subtype as 1909.21 (United States), 1893.36 (Japan), 981.76 (France), and 1714.89 (India). We estimated their migration pattern with time to and from different continents. The origin location of genotype 2 was estimated to be France instead of previous postulated African origin. This can be related to slave trade, French colonization, and previous studies on specific geographic regions only. HCV genotypes/subtypes showed transmission and expansion due to factors like World War II, iatrogenic infections, "baby boomer" population, inefficient medical screening, intravenous drug use, decline due to antiviral therapy introduction. Our study provides novel and extensive information about the evolutionary history and spatiotemporal spread of the HCV genotypes responsible for most infections worldwide.

Full-length sequence analysis of hepatitis C virus genotype 3b strains and development of an in vivo infectious 3b cDNA clone

IMPORTANCE

HCV genotype 3b is a difficult-to-treat subtype, associated with accelerated progression of liver disease and resistance to antivirals. Moreover, its prevalence has significantly increased among persons who inject drugs posing a serious risk of transmission in the general population. Thus, more genetic information and antiviral testing systems are required to develop novel therapeutic options for this genotype 3 subtype. We determined the complete genomic sequence and complexity of three genotype 3b isolates, which will be beneficial to study its biology and evolution. Furthermore, we developed a full-length in vivo infectious cDNA clone of genotype 3b and showed its robustness and genetic stability in human-liver chimeric mice. This is, to our knowledge the first reported infectious cDNA clone of HCV genotype 3b and will provide a valuable tool to evaluate antivirals and neutralizing antibodies in vivo, as well as in the development of infectious cell culture systems required for further research.

The distribution of hepatitis C viral genotypes shifted among chronic hepatitis C patients in Yunnan, China, between 2008-2018

OBJECT

The hepatitis C virus (HCV) is prevalent across China, with a distinctive genotypic distribution that varies by geographical region and mode of transmission. Yunnan is one such geographical region wherein the local population continues to experience a high level of HCV infection, severely straining public health resources. This high prevalence is likely due to the increased incidence of intravenous drug use in that region, as Yunnan is a major point of entry for illegal heroin into China.

METHODS

We investigated 510 individuals with chronic HCV infections in Yunnan Province from 2008 through 2018. Using reverse transcription PCR and Sanger sequencing to amplify and sequence samples. Bayesian analyses was performed to estimate the common ancestors and Bayesian skyline plot to estimate the effective viral population size. Molecular network was conducted to explore the characteristics of HCV transmission.

RESULTS

We successfully amplified and sequenced a total of 503 viral samples and genotyped each as either 3b (37.6%), 3a (21.9%), 1b (19.3%), 2a (10.5%), HCV-6 (10.1%), or 1a (0.6%). Over this 11-year period, we observed that the proportion of 3a and 3b subtypes markedly increased and, concomitantly, that the proportion of 1b and 2a subtypes decreased. We also performed Bayesian analyses to estimate the common ancestors of the four major subtypes, 1b, 2a, 3a, and 3b. Finally, we determined that our Bayesian skyline plot and transmission network data correlated well with the changes we observed in the proportions of HCV subtypes over time.

CONCLUSIONS

Taken together, our results indicate that the prevalence of HCV 3a and 3b subtypes is rapidly increasing in Yunnan, thus demonstrating a steadily growing public health requirement to implement more stringent preventative and therapeutic measures to curb the spread of the virus.