Determination of hepatitis C virus subtype prevalent in Sindh, Pakistan: a phylogenetic analysis.

Hepatitis is a major public health issue, affecting 10-17 million people worldwide, with its prevalence continuously increasing. The Hepatitis C virus (HCV) is responsible for liver related diseases, which include liver cirrhosis, hepatocellular carcinoma, and chronic hepatitis. Pakistan is experiencing a serious rise in HCV cases. This study aimed to assess the prevalence and distribution of HCV genotypes in Sindh, Pakistan. Serum samples from HCV-positive patients were collected from various local hospitals in Sindh. These samples were first screened for HCV antibodies using ELISA. Samples that tested positive for HCV RNA underwent further genotyping through sequencing using the standard Sanger method. The genotypes were identified by comparing the sequences with those available in the National Center for Biotechnology Information (NCBI) database, and a phylogenetic tree was constructed. The phylogenetic analysis showed that all isolates in this study were clustered with genotypes 3a and 3b, except for one sequence that was clustered with genotype 1a. No isolates were found to be clustered with reference genomes of genotypes 2, 4, 5, 6, and 7 suggesting that genotype 3a is endemic in this region. The analyzed sequences demonstrated a 98% similarity with reference and isolated sequences. In summary, sequencing of the HCV 5' UTR essential for identifying the predominant genotype of HCV RNA in the Sindh region Further research on the distribution of HCV genotypes in other regions of Pakistan could aid in improving screening processes, identifying more effective treatment options, and developing suitable prevention strategies.

Community-Based Screening for Hepatitis B and C Infectivity Using Two Quantitative Antigens to Identify Endemic Townships.

Screening and linkage to care are essential to achieve viral hepatitis elimination before 2030. The accurate identification of endemic areas is important for controlling diseases with geographic aggregation. Viral activity drives prognosis of chronic hepatitis B and hepatitis C virus infection. This screening was conducted in Chiayi County from 2018-2019. All residents aged 30 years or older were invited to participate in quantitative HBsAg (qHBsAg) and HCV Ag screening. Among the 4010 participants (male:female = 1630:2380), the prevalence of qHBsAg and HCV Ag was 9.9% (396/4010) and 4.1% (163/4010), respectively. High-prevalence townships were identified, three for qHBsAg > 15% and two for HCV Ag > 10%. The age-specific prevalence of qHBsAg was distributed in an inverse U-shape with a peak (16.0%, 68/424) for subjects in their 40 s; for HCV, prevalence increased with age. Concentrations of qHBsAg < 200 IU/mL were found in 54% (214/396) of carriers. The rate of oral antiviral treatment for HCV was 75.5% (114/151), with subjects younger than 75 years tending to undergo treatment (85.6% vs. 57.4%, p < 0.001). QHBsAg and HCV Ag core antigens can reflect the concentration of the viral load, which serves as a feasible screening tool. Using quantitative antigen screening for hepatitis B and C in community-based screening, two hyperendemic townships were identified from an endemic county.

A Highly Divergent Hepacivirus Identified in Domestic Ducks Further Reveals the Genetic Diversity of Hepaciviruses.

Hepaciviruses represent a group of viruses that pose a significant threat to the health of humans and animals. During the last decade, new members of the genus Hepacivirus have been identified in various host species worldwide, indicating the widespread distribution of genetically diversified hepaciviruses among animals. By applying unbiased high-throughput sequencing, a novel hepacivirus, provisionally designated Hepacivirus Q, was discovered in duck liver samples collected in Guangdong province of China. Genetic analysis revealed that the complete polyprotein of Hepacivirus Q shares 23.9-46.6% amino acid identity with other representatives of the genus Hepacivirus. Considering the species demarcation criteria for hepaciviruses, Hepacivirus Q should be regarded as a novel hepacivirus species of the genus Hepacivirus within the family Flaviviridae. Phylogenetic analyses also indicate the large genetic distance between Hepacivirus Q and other known hepaciviruses. Molecular detection of this novel hepacivirus showed an overall prevalence of 15.9% in duck populations in partial areas of Guangdong province. These results expand knowledge about the genetic diversity and evolution of hepaciviruses and indicate that genetically divergent hepaciviruses are circulating in duck populations in China.

A Novel Subtype of Bovine Hepacivirus Identified in Ticks Reveals the Genetic Diversity and Evolution of Bovine Hepacivirus.

Hepaciviruses represent a group of viruses that pose a significant threat to the health of humans and animals. New members of the genus Hepacivirus in the family Flaviviridae have recently been identified in a wide variety of host species worldwide. Similar to the Hepatitis C virus (HCV), bovine hepacivirus (BovHepV) is hepatotropic and causes acute or persistent infections in cattle. BovHepVs are distributed worldwide and classified into two genotypes with seven subtypes in genotype 1. In this study, three BovHepV strains were identified in the samples of ticks sucking blood on cattle in the Guangdong province of China, through unbiased high-throughput sequencing. Genetic analysis revealed the polyprotein-coding gene of these viral sequences herein shared 67.7-84.8% nt identity and 76.1-95.6% aa identity with other BovHepVs identified worldwide. As per the demarcation criteria adopted for the genotyping and subtyping of HCV, these three BovHepV strains belonged to a novel subtype within the genotype 1. Additionally, purifying selection was the dominant evolutionary pressure acting on the genomes of BovHepV, and genetic recombination was not common among BovHepVs. These results expand the knowledge about the genetic diversity and evolution of BovHepV distributed globally, and also indicate genetically divergent BovHepV strains were co-circulating in cattle populations in China.

Expression of HCV genotype-4 core antigen in prokaryotic E. coli system for diagnosis of HCV infection in Egypt.

BACKGROUND: Egypt has a high prevalence of hepatitis C virus (HCV) infection with 92.5% of genotype-4. AIM: This study aimed to clone and express the core gene of HCV genotype-4 for using it to develop a highly sensitive, specific, and cost-effective diagnostic assay for detecting HCV infection. METHODS: Using synthetic HCV genotype-4 core gene, pET15b as E. coli expression vector, and 1 mM lactose as inducer, the HCV core protein (MW 17 kDa) was expressed in the form of inclusion bodies (IBs) that was purified and solubilized using 8 M guanidinium HCl. The recombinant core protein was in vitro refolded by a rapid dilution method for further purification using weak cation exchange liquid chromatography. The immunogenicity of the purified protein was tested by ELISA using 129 serum samples. RESULTS: The recombinant core protein was successfully expressed and purified. The results also showed that the in-house anti-HCV core assay is accurate, specific (~96.6%), and highly sensitive (~100%) in accordance with the commercial ELISA kit. CONCLUSION: The sensitivity, specificity, and reproducibility of the developed assay were high and promising to be used as a screening assay for detecting HCV infection.

First identification and genomic characterization of equine hepacivirus sub-type 3 strain in China.

Equine Hepacivirus (EqHV) is a newly discovered equine virus that is classified under the Hepacivirus genus of the Flaviviridae family. There are three sub-types of EqHV worldwide namely; sub-types 1-3. The majority of EqHV sub-type 1 strains were found in China. While different sub-types have been found in Japan and USA, therefore, to investigate whether the other sub-types of EqHV strains were present in China, a total of 60 horse serum samples were collected and screened for EqHV RNA through RT-PCR. The results revealed that 19 serum samples were RNA-positive (19/60) and the EqHV detection rate was 31.67%. One EqHV strain named GD23 was obtained and its near-complete genome sequence was acquired. Analysis of nucleotide p-distance with reference to the entire polyprotein gene revealed that GD23 was classified into sub-type 3. In addition, the phylogenetic analysis demonstrated that GD23 was clustered together with EqHV strains of sub-type 3 in other countries. The present study is the first to identify an EqHV sub-type 3 strain in China.

Fluoxazolevir inhibits hepatitis C virus infection in humanized chimeric mice by blocking viral membrane fusion.

Fluoxazolevir is an aryloxazole-based entry inhibitor of hepatitis C virus (HCV). We show that fluoxazolevir inhibits fusion of HCV with hepatic cells by binding HCV envelope protein 1 to prevent fusion. Nine of ten fluoxazolevir resistance-associated substitutions are in envelope protein 1, and four are in a putative fusion peptide. Pharmacokinetic studies in mice, rats and dogs revealed that fluoxazolevir localizes to the liver. A 4-week intraperitoneal regimen of fluoxazolevir in humanized chimeric mice infected with HCV genotypes 1b, 2a or 3 resulted in a 2-log reduction in viraemia, without evidence of drug resistance. In comparison, daclatasvir, an approved HCV drug, suppressed more than 3 log of viraemia but is associated with the emergence of resistance-associated substitutions in mice. Combination therapy using fluoxazolevir and daclatasvir cleared HCV genotypes 1b and 3 in mice. Fluoxazolevir combined with glecaprevir and pibrentasvir was also effective in clearing multidrug-resistant HCV replication in mice. Fluoxazolevir may be promising as the next generation of combination drug cocktails for HCV treatment.

Impact of virus subtype and host IFNL4 genotype on large-scale RNA structure formation in the genome of hepatitis C virus.

Mechanisms underlying the ability of hepatitis C virus (HCV) to establish persistent infections and induce progressive liver disease remain poorly understood. HCV is one of several positive-stranded RNA viruses capable of establishing persistence in their immunocompetent vertebrate hosts, an attribute previously associated with formation of large-scale RNA structure in their genomic RNA. We developed novel methods to analyze and visualize genome-scale ordered RNA structure (GORS) predicted from the increasingly large data sets of complete genome sequences of HCV. Structurally conserved RNA secondary structure in coding regions of HCV localized exclusively to polyprotein ends (core, NS5B). Coding regions elsewhere were also intensely structured based on elevated minimum folding energy difference (MFED) values, but the actual stem-loop elements involved in genome folding were structurally poorly conserved, even between subtypes 1a and 1b. Dynamic remodeling was further evident from comparison of HCV strains in different host genetic backgrounds. Significantly higher MFED values, greater suppression of UpA dinucleotide frequencies, and restricted diversification were found in subjects with the TT genotype of the rs12979860 SNP in the IFNL4 gene compared to the CC (nonexpressing) allele. These structural and compositional associations with expression of interferon-λ4 were recapitulated on a larger scale by higher MFED values and greater UpA suppression of genotype 1 compared to genotype 3a, associated with previously reported HCV genotype-associated differences in hepatic interferon-stimulated gene induction. Associations between innate cellular responses with HCV structure and further evolutionary constraints represent an important new element in RNA virus evolution and the adaptive interplay between virus and host.

Prevalence of Hepatitis C Virus in an Endemic Area of Thailand: Burden Assessment toward HCV Elimination.

Chronic hepatitis C virus (HCV) infection can lead to liver cirrhosis and hepatocellular carcinoma. To eliminate HCV infection in an endemic area, an epidemiological baseline of the current HCV infection in the population is required. We therefore aimed to evaluate the HCV burden in the Thai Province of Phetchabun, which has the highest HCV infection rate in the country. Toward this, a province-wide district-based representative sampling of 4,769 individuals ages 35-64 years previously shown to represent high-risk age-groups were tested for anti-HCV antibodies using the automated chemiluminescent microparticle assays. Active HCV infection and subsequent genotyping were determined from serologically reactive samples by amplification of the HCV core gene. We found that 6.9% (327/4,769) were anti-HCV positive, of which 75.8% (248/327) had detectable HCV RNA and 5.8% (19/327) were in the presence of hepatitis B virus coinfection. Nucleotide sequencing and phylogenetic analysis revealed that HCV genotype 6 was the most prevalent (41%, 101/248), followed by genotype 3 (31%, 78/248), and genotype 1 (28%, 69/248). Socioeconomic and demographic factors including male gender, education, and agricultural work were associated with HCV seropositivity. From these results, we defined the regional HCV genotypes and estimated the HCV burden necessary toward the implementation of pan-genotypic direct-acting antivirals, which may be appropriate and effective toward the diversity of genotypes identified in this study. Micro-elimination of HCV in Phetchabun may serve as a model for a more comprehensive coverage of HCV treatment in Thailand.

A cross-sectional study of real life data of HCV from Turkey south region.

INTRODUCTION: This study investigated demographic characteristics and the prevalence of viremia among anti-HCV-positive patients. METHODOLOGY: Hospital records of adult patients with anti-HCV positivity between June 2016 and October 2018 were screened retrospectively. Demographic characteristics, genotype distribution, history of injection drug use (IDU), treatment data of HCV RNA-positive patients were investigated. RESULTS: The rate of anti-HCV seropositivity was 1.7% and 54.5% of these were viremic. 69.5% of the 869 viremic patients were male. The mean age was 62 ± 15 (18-95) years for women and 42 ± 19 (18-90) years for men (p < 0.0001). 42.7% of these patients had IDU history. Regarding age, patients with IDU history accounted for 95% of the 18-29 age group. The most common genotype in patients younger than 40 was genotype 3, and genotype 1b in those older than 40. Only 52% of viremic patients had received DAA therapy. Also, 62.2% of patients aged < 40 and 36% of patients > 40 did not receive treatment (p < 0.0001). The SVR12 rate in patients receiving DAA treatment and follow-up was 100%; SVR24 was 99.5%. CONCLUSIONS: A shift in the demographic structure of HCV-infected patients due to the changing trends of the HCV transmission mode was observed in this study. On the other hand, the proportion of patients who received DAA therapy was low. A substantial proportion of untreated patients were young with a history of IDU. This indicates that without strategies targeting the patients, the patient load due to HCV-related cirrhosis and hepatocellular carcinoma may persist in the future.

Substitution of the CD81 Binding Site and ß-Sandwich Area in E2 of HCV in Cambodia.

The high genetic variability of hepatitis C virus (HCV) is the main obstacle to developing a vaccine. E2 has attracted attention for vaccine development because targeting this protein could potentially overcome issues related to the genetic diversity of HCV. In this study, we analyzed HCV genes in the general population of Cambodia and investigated the E2 locus as a candidate for vaccine development. HCV sero-epidemiological surveys were conducted between the period 2010 and 2014, with an HCV RNA-positive rate of 1.3% (11/868). Follow-up blood samples were collected from four anti-HCV- and HCV RNA- positive patients (genotype 1b: 2 cases, 6e: 1 case, 6r: 1 case) after 4.12 years. Analysis of HCV full-length nucleotide sequences in paired specimens revealed that the mutation rates of HCV genotypes 1b and 6e/6r were 1.61-2.03 × 10-3 and 2.52-2.74 × 10-3 substitutions/site/year, respectively. Non-synonymous substitutions were detected in HVR1, the front layer of the CD81 binding site, and the ß-sandwich, but not in the N-terminal region or adjacent to the CD81 binding site. Therefore, we conclude that the CD81 binding site is a promising locus for HCV vaccine development.

Hepatitis-C Virus and Cirrhosis: An Overview from Khyber Pakhtunkhwa Province of Pakistan.

Hepatitis C virus (HCV) leads to liver cirrhosis and carcinoma worldwide. The data of HCV cirrhotic patients were collected from hospitals of Peshawar in the period from 2015 to 2018. A total sample of 267 patients, in the age limit (>19 and <87 years) were found to be cirrhotic and HCV positive. The samples were analyzed through different tests, that is, raised alkaline phosphatase (410 IU/L), aspartate aminotransferase (209 U/L), and reverse transcription-polymerase chain reaction (PCR) viral load (>5,000,000 IU/mL). The mean and standard deviation (SD) of alanine transaminase and alpha fetoprotein were noted, (121.46 ± 29.23) and (43.09 ± 28.08), respectively. Samples of HCV cirrhotic patients (59.6% males and 40.4% females) were included and their mean age and SD of the patients was 49.62 ± 12.65 years. The Child-Turcotte-Pugh Score system was assessed on the base of liver disease. High blood pressure was observed in 26.2%, low in 40.8%, and normal in 33% of patients. The ascites was recorded high in 59% patients (male 38.6%, female 20.6%) and the level of albumin was abnormal in 64.5% patients. Furthermore, multiplex PCR was run to determine HCV genotypes. The frequency of HCV genotype 3a was 47.9%, 2a and 3b was 11%, 1a was 6%, and 1b was 1%; 4.1% were mixed genotypes and 18.7% were untypable genotypes in these patients. The HCV genotype 3a was found a major prevalent genotype in Khyber Pakhtunkhwa patients and it was observed that the HCV cirrhosis issue was significantly increased in the province.

Impact of hepatitis C virus genotype 3 on liver disease progression in a Chinese national cohort.

BACKGROUND: Hepatitis C virus (HCV) genotype 3, particularly subtype 3b, is increasing in prevalence and distribution in China. This study evaluated the prevalence, regional distribution, clinical characteristics, host factors, treatment outcomes, and disease progression of patients with HCV genotype 3 in China. METHODS: A 5-year follow-up was preceded by a cross-sectional study. Treatment choices were at the discretion of treating physicians. Estimated infection time to overall-disease-progression (defined by ≥1 of: newly diagnosed cirrhosis; cirrhosis at baseline, Child-Turcotte-Pugh score increased 2 points or more; progression from compensated cirrhosis to decompensated cirrhosis; hepatocellular carcinoma; liver transplantation; or death) was calculated using the Kaplan-Meier method. Cox regression analyses were conducted to evaluate the risk factors for disease progression. RESULTS: The cross-sectional study enrolled 997 patients, including 91 with HCV genotype 3 infection. Among them, subtype 3b (57.1%) was more dominant than subtype 3a (38.5%). Five hundred and twelve patients were included into the follow-up phase. Among patients analyzed for estimated infection time to overall-disease-progression, 52/304 (17.1%) patients with HCV genotype 1 and 4/41 (9.8%) with HCV genotype 3 (4/26 with genotype 3b, 0/13 with genotype 3a, and 0/2 with undefined subtype of genotype 3) experienced overall-disease-progression. Patients with HCV genotype 3 were younger than those with genotype 1 (mean age: 39.5 ±â€Š8.7 vs. 46.9 ±â€Š13.6 years) and demonstrated more rapid disease progression (mean estimated infection time to overall-disease-progression 27.1 vs. 35.6 years). CONCLUSIONS: HCV genotype 3, specifically subtype 3b, is associated with more rapid progression of liver disease. Further analysis to compare HCV subtype 3a and 3b is needed in high prevalence regions. TRIAL REGISTRATION: NCT01293279, https://clinicaltrials.gov/ct2/show/NCT01293279; NCT01594554, https://clinicaltrials.gov/ct2/show/NCT01594554.

Further Evidence for in Utero Transmission of Equine Hepacivirus to Foals.

(1) Background: Equine hepacivirus (EqHV), also referred to as non-primate hepacivirus (NPHV), infects horses-and dogs in some instances-and is closely related to hepatitis C virus (HCV) that has infected up to 3% of the world's human population, causing an epidemic of liver cirrhosis and cancer. EqHV also chronically infects the liver of horses, but does not appear to cause serious liver damages. Previous studies have been looking to identify route(s) of EqHV transmission to and between horses. (2) Methods: In this retrospective study, we sought to evaluate the prevalence of vertical transmission taking place in utero with measuring by quantitative RT-PCR the amounts of EqHV genome in samples from 394 dead foals or fetuses, paired with the allantochorion whenever available. (3) Results: Detection of EqHV in three foals most likely resulted from a vertical transmission from the mares to the fetuses, consistent with the in utero transmission hypothesis. In support of this observation, the presence of EqHV genome was found for the first time in two of the allantochorions. (4) Conclusions: As seemingly benign viruses could turn deadly (e.g., Zika flavivirus) and EqHV happens to have infected a significant proportion of the world's horse herds, EqHV infectious cycle should be further clarified.

Molecular dynamics and docking reveal the potency of novel GTP derivatives against RNA dependent RNA polymerase of genotype 4a HCV.

AIM: To work on Hepatitis C Virus (HCV), one of the major causes of liver cirrhosis and hepatocellular carcinoma, polymerase of genotype 4a that have no solved structures deposited in the protein data bank (PDB) yet. Understanding the dynamics and testing some novel inhibitors are also covered. MATERIALS AND METHODS: Molecular Dynamics Simulation (MDS) is performed for a period of 1 µs on comparatively modeled then validated NS5b of subtype 4a. Following MDS analysis, molecular docking is performed to test the inhibitory performance of eight novels suggested guanosine derivatives using 181 different conformations of the protein model gathered during the MDS run after the equilibration period. KEY FINDINGS: The results yield that the eight modified, at position 2', GTP derivatives (fluorine, Hydroxyl, and sulphonyl oxydanyl) have binding energies comparable to the parent molecule, GTP. Besides, the eight suggested compounds have lower binding energies (and hence better in binding) compared to sofosbuvir (a drug approved by FDA in 2013 against HCV) and ribavirin (a wide range acting antiviral drug used before against HCV). SIGNIFICANCE: Combined molecular dynamics and molecular docking are able to test the hypothesis of HCV polymerase dynamics doesn't affect the nucleotides (or nucleotide inhibitors) binding to its active site. Despite the reported highly dynamic subtype 4a of HCV; all the nucleotide inhibitors under the study are able to, tightly, bind to NS5b of genotype 4a. This behavior is reported before for the Zika virus polymerase, as well.

Construction and characterization of Genotype-3 hepatitis C virus replicon revealed critical genotype-3-specific polymorphism for drug resistance and viral fitness.

Hepatitis C virus (HCV), a major causative agent of chronic hepatitis, is a positive-stranded RNA virus and has a high degree of genetic diversity due to its error-prone RNA-dependent RNA polymerase. Development of direct-acting antiviral agents (DAAs) has greatly improved the therapeutic outcome of chronic hepatitis C patients. However, naturally existing resistance-associated variants (RAVs) or occurrence of resistance-associated substitutions (RASs) in the HCV genome may impose a challenge to the long-term success of the DAA-based therapies. Genotype-3 HCV is the most difficult genotype to treat by DAAs, but the underlying molecular mechanisms remain to be explored. Here we developed a novel genotype-3a subgenomic replicon PR87A7 by screening a HCV cDNA pool amplified from a patient serum RNA. PR87A7 replicon displayed strong resistance to anti-NS3 DAAs, mainly owing to a genotype-3-specific polymorphism 168Q in NS3. Introduction of NS3 168Q into a genotype-2a JFH1 strain rendered resistance to anti-NS3 DAAs while greatly diminished the viral replication, and yet this fitness defect can be rescued by additional genotype-3-specific polymorphism. In conclusion, we developed a novel genotype-3a subgenomic replicon by a functional screening approach, and revealed genotype-3-specfic amino acid residues that confer resistance to anti-NS3 DAAs while retaining viral fitness.

Presence of a Novel Subtype of Bovine Hepacivirus in China and Expanded Classification of Bovine Hepacivirus Strains Worldwide into 7 Subtypes.

The newest member of the Hepacivirus genus, bovine hepacivirus (BovHepV), was first identified in cattle in 2015 and is a novel hepacivirus C virus (HCV)-like virus. This virus has been detected in five countries so far and is classified into four subtypes. Bovine serum is commonly used for cell cultures and is considered the major source of viral contamination of pharmaceutical products. In this study, bovine serum samples were collected from seven countries located in Asia, America, Oceania, and Europe and were tested for BovHepV RNA using nested PCR, in order to: (i) obtain more knowledge on the geographical distribution and subtypes of BovHepV; and (ii) detect the potential contamination of BovHepV in commercial bovine serum samples used for cell culture propagation. The results demonstrated that bovine serum samples from individual donor cattle in China contained BovHepV RNA. After PCR, sequencing, and assembly, the genomes of the Chinese BovHepV strains were obtained. Genetic analysis of the polyprotein gene revealed a protein identity of <77% and a nucleotide identity of <85% between the Chinese BovHepV strains and all other previously reported BovHepV strains. Using cut-off values for determination of HCV genotypes and subtypes, BovHepV strains worldwide were classified into one unique genotype and seven subtypes. The BovHepV strains identified in the present study were classified into a novel subtype, which was provisionally designated subtype G. The genetic relationships among the different BovHepV subtypes were further confirmed through phylogenetic analysis. The present study provides critical insights into BovHepV's geographical distribution and genetic variability.

Interferon lambda 4 impacts the genetic diversity of hepatitis C virus.

Hepatitis C virus (HCV) is a highly variable pathogen that frequently establishes chronic infection. This genetic variability is affected by the adaptive immune response but the contribution of other host factors is unclear. Here, we examined the role played by interferon lambda-4 (IFN-λ4) on HCV diversity; IFN-λ4 plays a crucial role in spontaneous clearance or establishment of chronicity following acute infection. We performed viral genome-wide association studies using human and viral data from 485 patients of white ancestry infected with HCV genotype 3a. We demonstrate that combinations of host genetic variants, which determine IFN-λ4 protein production and activity, influence amino acid variation across the viral polyprotein - not restricted to specific viral proteins or HLA restricted epitopes - and modulate viral load. We also observed an association with viral di-nucleotide proportions. These results support a direct role for IFN-λ4 in exerting selective pressure across the viral genome, possibly by a novel mechanism.

Rapid decrease in titer and breadth of neutralizing anti-HCV antibodies in HIV/HCV-coinfected patients who achieved SVR.

The main targets for neutralizing anti-hepatitis C virus (HCV) antibodies (HCV-nAbs) are the E1 and E2 envelope glycoproteins. We have studied the characteristics of HCV-nAbs through a retrospective study involving 29 HIV/HCV-coinfected patients who achieved sustained virological response (SVR) with peg-IFNα + ribavirin anti-HCV therapy. Plasma samples at baseline and week 24 after SVR were used to perform neutralization assays against five JFH1-based HCV recombinant viruses coding for E1 and E2 from genotypes 1a (H77), 1b (J4), 2a (JFH1), 3a (S52) and 4a (ED43). At baseline, the majority of plasma samples neutralized 1a, 1b, 2a, and 4a, but not 3a, genotypes. Twenty-four weeks following SVR, most neutralizing titers declined substantially. Furthermore, titers against 3a and 2a were not detected in many patients. Plasma samples with high HCV-nAb titers neutralized all genotypes, and the highest titers at the starting point correlated with the highest titers at week 24 after SVR. In conclusion, high titers of broad-spectrum HCV-nAbs were detected in HIV/HCV-coinfected individuals, however, those titers declined soon after SVR.

A highly divergent hepacivirus-like flavivirus in domestic ducks.

Using random amplification and reverse transcription-PCR, a novel RNA virus was detected in sera of domestic ducks. The full genome of the virus was determined for three strains, identifying the first hepacivirus-like flavivirus in birds. The virus, that we tentatively named duck hepacivirus-like virus (DuHV), possesses several unique molecular features, such as possession of the largest hepacivirus-like polyprotein gene and a Pegivirus A-like internal ribosome entry site. Sequence comparisons and phylogenetic and sliding-window analyses indicated that DuHV is most closely related to, but highly divergent from, the known hepaciviruses. DuHV was detected in 69.7 % of 185 serum samples from four duck species and in 31 of 33 flocks from five provinces of China, reflecting a high prevalence in duck populations and a wide geographical distribution. The detection of DuHV in the same flock in November 2018 and April 2019 suggested that persistent infection can be established in the infected ducks.