Hepatitis C virus genotyping based on Core and NS5B regions in Cameroonian patients

A decade-long retrospective study of hepatitis C virus genetic diversity in Cameroon, 2013-2023: presence of a high proportion of unsubtypable and putative recombinant HCV strains

While treatment options for hepatitis C virus (HCV) infection have expanded considerably over the past decade thanks to the development of pan-genotypic therapies, genotype testing remains a prerequisite for treatment in sub-Saharan African countries, including Cameroon, where multiple HCV genotypes and subtypes exist. The main objective of this study was to describe the trend in the distribution of HCV genotypes and subtypes from 2013 to 2023 in the Cameroonian population. Viral loads were determined using the Abbott real-time assay, and genotyping/subtyping was based on nested and semi-nested reverse transcription polymerase chain reaction (RT-PCR) amplification of the regions encoding the core and non-structural protein 5B (NS5B) regions, respectively, followed by sequencing and phylogenetic analysis. A total of 512 patients with NS5B and core sequencing results were included in our study. Genotyping revealed a predominance of both genotype 4 (38.48%) and genotype 1 (37.11%), followed by genotype 2, detected in 22.46% of patients. Interestingly, 10 samples (1.95%) had discordant genotypes in both regions, suggesting the presence of putative recombinant forms of HCV. Twelve different subtypes were detected during the study period, with a predominance of subtypes 4f (18.95%) and 1e (16.02%). Furthermore, phylogenetic analysis failed to assign a subtype to a relatively high proportion of sequences (38.67%) for the two genomic regions, and their classification was limited to genotype assignment. The frequency distribution of HCV genotypes did not show any statistical difference according to year or sex. These results confirm the genetic diversity of HCV in Cameroon and the potential for the generation of recombinant strains.

'Unusual' HCV genotype subtypes: origin, distribution, sensitivity to direct-acting antiviral drugs and behaviour on antiviral treatment and retreatment

The high genetic diversity of hepatitis C virus (HCV) has led to the emergence of eight genotypes and a large number of subtypes in limited geographical areas. Currently approved pangenotypic DAA regimens have been designed and developed to be effective against the most common subtypes (1a, 1b, 2a, 2b, 2c, 3a, 4a, 5a and 6a). However, large populations living in Africa and Asia, or who have migrated from these regions to industrialised countries, are infected with 'unusual', non-epidemic HCV subtypes, including some that are inherently resistant to currently available direct-acting antiviral (DAA) drugs due to the presence of natural polymorphisms at resistance-associated substitution positions. In this review article, we describe the origin and subsequent global spread of HCV genotypes and subtypes, the current global distribution of common and unusual HCV subtypes, the polymorphisms naturally present in the genome sequences of unusual HCV subtypes that may confer inherently reduced susceptibility to DAA drugs and the available data on the response of unusual HCV subtypes to first-line HCV therapy and retreatment. We conclude that the problem of unusual HCV subtypes that are inherently resistant to DAAs and its threat to the global efforts to eliminate viral hepatitis are largely underestimated and warrant vigorous action.

Hepatitis C virus subtype diversity and transmission clusters characteristics among drug users in Zhuhai, South China

BACKGROUND

Hepatitis C virus (HCV) infection poses a major public health challenge globally, especially among injecting drug users. China has the world's largest burden of HCV infections. However, little is known about the characteristics of transmission networks among drug user populations. This study aims to investigate the molecular epidemiology and transmission characteristics of HCV infections among drug users in Zhuhai, a bustling port city connecting Mainland China and its Special Administrative Regions.

METHODS

Participants enrolled in this study were drug users incarcerated at Zhuhai's drug rehabilitation center in 2015. Their sociodemographic and behavioral information, including gender, promiscuity, drug use method, and so forth, was collected using a standardized questionnaire. Plasmas separated from venous blood were analyzed for HCV infection through ELISA and RT-PCR methods to detect anti-HCV antibodies and HCV RNA. The 5'UTR fragment of the HCV genome was amplified and further sequenced for subtype identifications and phylogenetic analysis. The phylogenetic tree was inferred using the Maximum Likelihood method based on the Tamura-Nei model, and the transmission cluster network was constructed using Cytoscape3.8.0 software with a threshold of 0.015. Binary logistic regression models were employed to assess the factors associated with HCV infection.

RESULTS

The overall prevalence of HCV infection among drug users was 44.37%, with approximately 19.69% appearing to clear the HCV virus successfully. Binary logistic regression analysis revealed that those aged over 40, engaging in injecting drug use, and being native residents were at heightened risk for HCV infection among drug user cohorts. The predominant HCV subtypes circulating among those drug users were 6a (60.26%), followed by 3b (16.7%), 3a (12.8%), 1b (6.41%) and 1a (3.85%), respectively. Molecular transmission network analysis unveiled the presence of six transmission clusters, with the largest propagation cluster consisting of 41 individuals infected with HCV subtype 6a. Furthermore, distinct transmission clusters involved eight individuals infected with subtype 3b and seven with subtype 3a were also observed.

CONCLUSION

The genetic transmission networks revealed a complex transmission pattern among drug users in Zhuhai, emphasizing the imperative for a targeted and effective intervention strategy to mitigate HCV dissemination. These insights are pivotal for shaping future national policies on HCV screening, treatment, and prevention in port cities.

Glycylglycine promotes the solubility and antigenic utility of recombinant HCV structural proteins in a point-of-care immunoassay for detection of active viremia

BACKGROUND

Although E. coli is generally a well-opted platform for the overproduction of recombinant antigens as heterologous proteins, the optimization of expression conditions to maximize the yield of functional proteins remains empirical. Herein, we developed an optimized E. coli (BL21)-based system for the overproduction of soluble immunoreactive HCV core/envelope proteins that were utilized to establish a novel immunoassay for discrimination of active HCV infection.

METHODS

The core/E1-E2 genes were amplified and expressed in E. coli BL21 (DE3) in the absence/presence of glycylglycine. The antigenic performance of soluble proteins was assessed against 63 HCV-seronegative (Ab-) sera that included normal and interferent sera (HBV and/or chronic renal failure), and 383 HCV-seropositive (Ab+) samples that included viremic (chronic/relapsers) and recovered patients' sera. The color intensity (OD450) and S/Co values were estimated.

RESULTS

The integration of 0.1-0.4M glycylglycine in the growth media significantly enhanced the solubility/yield of recombinant core and envelope proteins by ~ 225 and 242 fold, respectively. This was reflected in their immunoreactivity and antigenic performance in the developed immunoassay, where the soluble core/E1/E2 antigen mixture showed 100% accuracy in identifying HCV viremic sera with a viral RNA load as low as 3800 IU/mL, without cross-reactivity against normal/interferent HCV-Ab-sera. The ideal S/Co threshold predicting active viremia (> 2.75) showed an AUC value of 0.9362 (95% CI: 0.9132 to 0.9593), with 87.64, 91.23% sensitivity and specificity, and 94.14, 82.11% positive and negative predictive values, respectively. The different panels of samples assayed with our EIA showed a good concordance with the viral loads and also significant correlations with the golden standards of HCV diagnosis in viremic patients. The performance of the EIA was not affected by the immunocompromised conditions or HBV co-infection.

CONCLUSION

The applicability of the proposed platform would extend beyond the reported approach, where glycylglycine, low inducer concentration and post-induction temperature, combined with the moderately-strong constitutive promoter enables the stable production of soluble/active proteins, even those with reported toxicity. Also, the newly developed immunoassay provides a cost-effective point-of-care diagnostic tool for active HCV viremia that could be useful in resource-limited settings.

903 Protein Saver cards: the best alternative for dried blood spot storage at room temperature for HCV RNA

Hepatitis C virus (HCV) infection remains a global health problem, detected only in the early stages by molecular tests. Molecular tests detect HCV RNA, which is very prone to degradation by ribonucleases, reason why blood samples must be transported and stored at − 20 °C, or even − 70 °C for long-term storage. Flinders Technology Associates (FTA) cards are a useful sampling collecting device for dry blood spot (DBS) storage, especially for low and middle-income countries (LMIC). In this study, we analyzed viral HCV RNA integrity for long-term storage at room temperature compared to − 20 °C using two different types of cards for DBS: FTA Classic and 903 Protein Saver cards. For this purpose, DBS were prepared on these cards using blood or plasma samples from HCV infected patients, and samples were analysed by conventional RT-PCR. Our results showed that 903 Protein Saver cards are the best and cheapest alternative for DBS storage at room temperature. In these conditions, we found that HCV RNA integrity lasted for up to 9 months.

Distribution of hepatitis C virus genotypes in Punjab region, Pakistan, based on a study of 4177 specimens

Hepatitis C virus (HCV) is a heterogenetic infectious agent that affects a huge proportion of population around the globe. Diverse distribution of multiple subtypes of HCV makes it mandatory and remarkably imperative to understand the genotypic distribution in target population. It could serve as an indictive guideline for the improvement of diagnostic methodologies, and development of effective therapies against this viral infection, in order to improve the infected patients' quality of life. This study included HCV infected patients presented to the diagnostic facility of the Centre for Applied Molecular Biology, University of Punjab, Lahore, between 2016 and 2019. During the 4 years of study, samples were collected from 4177 subjects. Our data revealed no significant differences regarding the prevalence of various genotypes between genders in the adult population. Genotyping was carried out by following the Ohno protocol. The obtained results shown that genotype 3a is the most frequent genotype and accounts for 66.29% of cases. Among other genotypes, 1a is 2.11%, 1b is 0.07%, 3b is 1.89%, 5a is 0.02%, while genome of 28.23% patients was untypable; 1.22% of the samples were non-detectable as viremic. An important concern is that this untypable genome in HCV infected patients may indicate possible mutation of HCV.

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.

Achieving a high cure rate with direct-acting antivirals for chronic Hepatitis C virus infection in Cameroon: a multi-clinic demonstration project

Objectives

Highly effective direct‐acting antivirals (DAAs) for Hepatitis C treatment are largely inaccessible in sub‐Saharan Africa. Data on treatment feasibility and outcomes in clinical settings are limited. We assessed the feasibility of achieving a high (≥90%) cure rate with DAAs in six gastroenterology clinics in Cameroon.

Methods

Patients with chronic Hepatitis C virus (HCV) infection were treated for 12 or 24 weeks with ledipasvir/sofosbuvir, ledipasvir/sofosbuvir/ribavirin or sofosbuvir/ribavirin, depending on the stage of liver disease and HCV genotype. The cure rate was defined as the proportion of patients with a sustained virological response 12 weeks after treatment completion (SVR12) among all treatment completers.

Results

We identified 190 HCV RNA positive patients between September‐2017 and August‐2018, 161 (84.7%) of whom started treatment. 105 (65.2%) were female, median age was 61.3 years [IQR = 55.9–66.9] and 11 (6.8%) were HIV‐positive. Median plasma HCV RNA was 6.0 log₁₀ IU/mL [IQR = 5.6–6.4]. HCV genotypes identified were 1 (34.8%), 2 (13.7%), 4 (50.9%), 1 and 4 (0.6%); 46 (28.6%) strains of 160 single‐genotype infections were non‐subtypeable. Of 158 treatment completers, 152 (96.2%, 95%CI = 91.9–98.6%) achieved SVR12. Six patients did not achieve SVR12: five carried HCV with NS5A resistance mutations and one with NS5B resistance mutations. Three patients died before and two after treatment completion. The most common adverse events were asthenia (12.0%), headache (11.4%) and dizziness (18.9%).

Conclusion

High cure rates of Hepatitis C with DAAs are achievable in clinical settings of Cameroon. However, the accessibility and provision of HCV screening, diagnosis, treatment, monitoring and care should be addressed for large‐scale implementation.