A novel hepatitis C virus (HCV) subtype from Somalia and its classification into HCV clade 3

Origin of hepatitis C virus genotype 3 in Africa as estimated through an evolutionary analysis of the full-length genomes of nine subtypes, including the newly sequenced 3d and 3e

We characterized the full-length genomes of nine hepatitis C virus genotype 3 (HCV-3) isolates: QC7, QC8, QC9, QC10, QC34, QC88, NE145, NE274 and 811. To the best of our knowledge, NE274 and NE145 were the first full-length genomes for confirming the provisionally assigned subtypes 3d and 3e, respectively, whereas 811 represented the first HCV-3 isolate that had its extreme 3' UTR terminus sequenced. Based on these full-length genomes, together with 42 references representing eight assigned subtypes and an unclassified variant of HCV-3, and 10 sequences of six other genotypes, a timescaled phylogenetic tree was reconstructed after an evolutionary analysis using a coalescent Bayesian procedure. The results indicated that subtypes 3a, 3d and 3e formed a subset with a common ancestor dated to ~202.89 [95% highest posterior density (HPD): 160.11, 264.6] years ago. The analysis of all of the HCV-3 sequences as a single lineage resulted in the dating of the divergence time to ~457.81 (95% HPD: 350.62, 587.53) years ago, whereas the common ancestor of all of the seven HCV genotypes dated to ~780.86 (95% HPD: 592.15, 1021.34) years ago. As subtype 3h and the unclassified variant were relatives, and represented the oldest HCV-3 lineages with origins in Africa and the Middle East, these findings may indicate the ancestral origin of HCV-3 in Africa. We speculate that the ancestral HCV-3 strains may have been brought to South Asia from Africa by land and/or across the sea to result in its indigenous circulation in that region. The spread was estimated to have occurred in the era after Vasco da Gama had completed his expeditions by sailing along the eastern coast of Africa to India. However, before this era, Arabians had practised slave trading from Africa to the Middle East and South Asia for centuries, which may have mediated the earliest spread of HCV-3.

Full-length genome sequences of five hepatitis C virus isolates representing subtypes 3g, 3h, 3i and 3k, and a unique genotype 3 variant

We characterized the full-length genomes of five distinct hepatitis C virus (HCV)-3 isolates. These represent the first complete genomes for subtypes 3g and 3h, the second such genomes for 3k and 3i, and of one novel variant presently not assigned to a subtype. Each genome was determined from 18-25 overlapping fragments. They had lengths of 9579-9660 nt and each contained a single ORF encoding 3020-3025 aa. They were isolated from five patients residing in Canada; four were of Asian origin and one was of Somali origin. Phylogenetic analysis using 64 partial NS5B sequences differentiated 10 assigned subtypes, 3a-3i and 3k, and two additional lineages within genotype 3. From the data of this study, HCV-3 full-length sequences are now available for six of the assigned subtypes and one unassigned. Our findings should add insights to HCV evolutionary studies and clinical applications.

Full-length sequences of 11 hepatitis C virus genotype 2 isolates representing five subtypes and six unclassified lineages with unique geographical distributions and genetic variation patterns

In this study, we characterized full-length hepatitis C virus (HCV) genome sequences for 11 genotype 2 isolates. They were isolated from the sera of 11 patients residing in Canada, of whom four had an African origin. Full-length genomes, each with 18-25 overlapping fragments, were obtained by PCR amplification. Five isolates represent the first complete genomes of subtypes 2d, 2e, 2j, 2m and 2r, while the other six correspond to variants that do not group within any assigned subtypes. These sequences had lengths of 9508-9825 nt and each contained a single ORF encoding 3012-3106 aa. Predicted amino acids were carefully inspected and unique variation patterns were recognized, especially for a 2e isolate, QC64. Phylogenetic analysis of complete genome sequences provides evidence that there are a total of 16 subtypes, of which 11 have been described here. Co-analysis with 68 partial NS5B sequences also differentiated 18 assigned subtypes, 2a-2r, and eight additional lineages within genotype 2, which is consistent with the analysis of complete genome sequences. The data from this study will now allow 10 assigned subtypes and six additional lineages of HCV genotype 2 to have their full-length genomes defined. Further analysis with 2021 genotype 2 sequences available in the HCV database indicated that the geographical distribution of these subtypes is consistent with an African origin, with particular subtypes having spread to Asia and the Americas.

Determination of HCV genotypes and viral loads in chronic HCV infected patients of Hazara Pakistan

Hepatitis C Virus (HCV) genotype and viral load are two significant predictive variables knowledge of which might persuade treatment decisions. The objective of the present study was to identify the distribution of different HCV genotypes circulating in the study area and to estimate viral load in chronically HCV infected patients. Out of total 305 HCV positive patients, 177 (58%) were males and 128 (42%) were females. Frequency breakup of the HCV positive patients was 169, 69, 38 and 29 from Abbottabad, Mansehra, Haripur and Battagram districts respectively. Out of the total 305 tested serum samples, 255 (83.06%) were successfully genotyped whereas 50 (16.4%) samples were found with unclassified genotypes. Among typable genotypes, 1a accounted for 21 (6.8%) 1b for 14 (4.6%), 2a for 4 (1.31%) 3a for 166 (54.42%) and genotype 3b for (8.19%). Twenty five (8.19%) patients were infected with mixed HCV genotypes. Viral load distribution was classified into three categories based on its viral load levels such as low (< 60, 0000 IU/mL), intermediate (60,0000-80,0000 IU/mL) and high (> 80,0000 IU/mL). The baseline HCV RNA Viral load in HCV genotype 3 infected patients was 50 (26.17%), 46 (24.08%) and 95 (49.73%) for low, intermediate and high categories respectively. For genotypes other than 3, these values for low, intermediate and high viral load categories were 50 (43.85), 35 (30.70) and 29 (25.43) respectively. Pre-treatment viral load in patients with untypable genotype was 19 (38.00%), 5 (20.00%) and 11 (44.00%) for low, intermediate and high viral load categories. Viral load distribution was also categorized sex wise; for males it was 58 (32.76%), 26 (14.68%) and 93 (52.54%) whereas for females it was 40 (31.25%), 34 (26.56%) and 54 (42.18%) for low, intermediate and high viral load respectively. In conclusion HCV genotype 3a is the most prevalent genotype circulating in Hazara Division like other parts of pakistan. Pre-treatment viral load is significantly high (p 0.014) in patients infected with HCV genotype 3 as compared to other genotypes.

Association of laboratory parameters with viral factors in patients with hepatitis C

Background and Aims

HCV infection may lead to hepatic fibrosis. In this study, we tried to determine whether there is any correlation of HCV genotypes and viral load to the clinical parameters such as ALT, AST, ALP, bilirubin, Hb level, patient's age and gender; and then correlated this association with disease progression in liver biopsy samples.

Methods

In cross-sectional and observational study, 6048 serum HCV RNA positive patients were chosen. The study consists of 53 months from March 2006 to September 2010. Patients were divided into three cohorts to validate our data. Statistical analysis and correlation of lab parameters with viral factors was determined by using SPSS version 16.

Results

The most prevalent genotype was 3 (70.9%) followed by 1 (13.3%) and 4 (7.4%), collectively. During Univariate analysis, in all cohorts; serum bilirubin, ALP, ALT and AAR showed significant correlation with genotypes, however multivariate analysis showed that all genotypes except 4a have no association with host biochemical markers. Disease progression was also independent of all genotypes. Serum ALP, ALT, bilirubin and viremea levels were significantly elevated in patients with genotype 4a. Viral load showed negative association with serum bilirubin (r = -0.112, P = 0.000) and ALP levels (r = -0.098, P = 0.000). We observed positive correlation of ALP and bilirubin levels, while negative associations of viral load with HCV liver disease progression.

Conclusion

Disease progression seems independent of the genotypes. Relationship between ALP and bilirubin with viral load may be an attractive marker to guess disease progression in patients with hepatitis C.

HCV genotype-specific correlation with serum markers: higher predictability for genotype 4a

Background

Several factors have been proposed to assess the clinical outcome of HCV infection. The correlation of HCV genotypes to possible serum markers in clinical prediction is still controversial. The main objective of this study was to determine the existence of any correlation between HCV genotypes to viral load and different clinical serum markers.

Methods

We performed a prospective cross-sectional and observational study. About 3160 serum HCV RNA positive patients were chosen from 4020 randomly selected anti-HCV positive patients. Statistical analysis was performed using the SPSS 16 software package. ROC (receiver operating characteristics) curves were used to compare diagnostic values of serum markers to predict genotypes.

Results

The most prevalent genotype was 3a (73.9%) followed by 1a (10.7%), 4a (6.4%) and 3b (6.1%) in Pakistani population. No correlation was found between viral load and serum markers for genotype 3a in a large no. of sample (n = 2336). While significant correlation was observed between viral load and AST in genotype 3b, ALP with viral load and ALT for genotype 1a. Patients with genotype 4a showed a significant inverse correlation with viral load and Hb level and AST with ALP. For genotype 4a, AUC (area under the curve) of ALT, ALP, AST, bilirubin, Hb level and viral load was 0.790, 0.763, 0.454, 0.664, 0.458 and 0.872 respectively.

Conclusions

In conclusion, there was a significant variable response of HCV genotypes with serum markers. Severity of disease is independent of serum marker level in genotype 3a, while the liver damage in genotype 4a may associate with viral cytopathic effect as well as the immune-mediated process. An index using six serum markers may correctly predict genotype 4a in patients with ≥75% accuracy.

HCV genotype distribution and possible transmission risks in Lahore, Pakistan

AIM: To investigate the prevalence of hepatitis C virus (HCV) genotypes and their association with possible transmission routes in the general population of Lahore, as the data exclusively related to this city is limited.

METHODS: Complete data regarding patient’s history, possible route of infection and biochemical tests was collected from the public hospital for 1364 patients. SPSS version 16 windows software was used for data analysis by univariate and multivariate techniques.

RESULTS: Age range ≤ 40 years showed high prevalence of HCV infection. HCV genotype 3a was dominant (55.9%), followed by 1a (23.6%), 4a (12.5%), 3b (3.2%), untypable (2.5%), 4b (1.2%) and mixed type (1.2%). Blood transfusion, dental surgery and barber shops were the main risk factors for HCV transmission. Genotype prevalence was independent of age (P = 0.971) and gender (P = 0.122) while risk factors showed a significant association with age (P = 0.000) and genotypes (P = 0.000). We observed an independent association of risk factors and genotype 3a, while patients with genotype 1 and 4 were mostly infected due to dental surgery blood transfusion and barber shops. Risk factors of intravenous drug use and sexual exposure were exclusively found in ≤ 40 years age group.

CONCLUSION: An increase in genotypes 1a and 4a suggest migration of people, possibly from Balochistan and the northern war-zone area. Government should focus on public education regarding infection routes.

Entire genome sequences of two new HCV subtypes, 6r and 6s, and characterization of unique HVR1 variation patterns within genotype 6

Hepatitis C virus genotype 6 currently contains 21 recognized subtypes, 6a-6u, for which 6r and 6s lack complete genome sequences. In this study, we entirely sequenced variants QC245 and QC66 from Cambodian immigrants in Canada representing subtypes 6r and 6s, respectively. The two genomes shared 75.3% nucleotide similarities to each other and 72.0-82.9% to 21 reference sequences representing subtypes 6a-6q, 6t-6u and variants km41 and gz52557. QC66 and QC245 displayed genome lengths of 9473 and 9450 nt and each contained a single open reading frame of 9051 nt. In 10 protein encoding regions QC245 and QC66 shared common sizes with TV249/6t and 537796/6l isolates, respectively. Phylogenetic analyses demonstrated that QC245 was more closely related to subtype 6f, but both QC66 and QC245 were subtypically different from all other genotype 6 subtypes. Our full-length sequence data confirmed the status of subtype 6r and 6s within genotype 6. Analysis of partial sequences revealed seven 6t and two 6s isolates that were all isolated from Cambodian immigrants. Analysis of the hypervariable region 1 sequences of 81 genotype 6 variants revealed two unique patterns of variation. First, most variants showed an amino acid deletion at the 4th position and second, many contained a basic residue at the 7th position. Possible roles of these two variation patterns are further discussed.

The phylogenetic analysis of hepatitis C virus isolates obtained from two Iranian carriers revealed evidence for a new subtype of HCV genotype 3

Classification of hepatitis C virus is based on phylogenetic analysis of the strains reported world wide. Different strains are classified within 6 major genotypes and several minor groups (subtypes). In addition to epidemiologic value of determining genotype/subtype of this virus, the result may change the therapeutic strategy used for a patient. During a survey on hepatitis C in Iran, we found two cases assigned as 1b genotype by PCR-RFLP on 5' UTR, but three based on core region sequencing. Fragments from 5' UTR, Core and NS5b regions were PCR-amplified and sequenced followed by phylogenetic analysis. Although the 5' UTR of this new strain is very similar to genotypes 1 and 6, analysis of core region classifies it in a separate branch of genotype 3, close to subtypes h and k. Further analysis of NS5b region put this new strain in a separate branch near other subtypes of genotype 3 and 4. These data are suggestive of a new subtype within genotype 3.

Genetic diversity and evolution of hepatitis C virus in the Latin American region

Hepatitis C virus (HCV) has been the subject of intense research and clinical investigations, as a consequence of the recognition of its major role in human disease. HCV evolution is a highly dynamic process. HCV exploits all known mechanisms of genetic variation, such as recombination and mutation, to ensure its survival. Like most RNA viruses, HCV circulates in vivo as a complex population of different but closely related variants, commonly referred to as a quasi species. This work describes the genetic variability of HCV in Latin America, with special emphasis on its diversification and recombination in this area of the world, and discusses how our knowledge of these issues can contribute to its control.

Consensus proposals for a unified system of nomenclature of hepatitis C virus genotypes

International standardization and coordination of the nomenclature of variants of hepatitis C virus (HCV) is increasingly needed as more is discovered about the scale of HCV-related liver disease and important biological and antigenic differences that exist between variants. A group of scientists expert in the field of HCV genetic variability, and those involved in development of HCV sequence databases, the Hepatitis Virus Database (Japan), euHCVdb (France), and Los Alamos (United States), met to re-examine the status of HCV genotype nomenclature, resolve conflicting genotype or subtype names among described variants of HCV, and draw up revised criteria for the assignment of new genotypes as they are discovered in the future. A comprehensive listing of all currently classified variants of HCV incorporates a number of agreed genotype and subtype name re-assignments to create consistency in nomenclature. The paper also contains consensus proposals for the classification of new variants into genotypes and subtypes, which recognizes and incorporates new knowledge of HCV genetic diversity and epidemiology. A proposal was made that HCV variants be classified into 6 genotypes (representing the 6 genetic groups defined by phylogenetic analysis). Subtype name assignment will be either confirmed or provisional, depending on the availability of complete or partial nucleotide sequence data, or remain unassigned where fewer than 3 examples of a new subtype have been described. In conclusion, these proposals provide the framework by which the HCV databases store and provide access to data on HCV, which will internationally coordinate the assignment of new genotypes and subtypes in the future.

A refined long RT-PCR technique to amplify complete viral RNA genome sequences from clinical samples: application to a novel hepatitis C virus variant of genotype 6

The goal of this study was to adapt a long RT-PCR technique to amplify large PCR fragments from the genome of hepatitis C virus (HCV) isolates using clinical samples. This was done by using a reverse transcriptase devoid of RNase H activity and a mixture of two antibody-bound thermostable polymerases to combine the high processivity of Taq and the high fidelity of Pwo with its 3'-->5' exonuclease activity. Other modifications included gentle handling during RNA extraction, the absence of tRNA and random primers, a two-step reverse transcription procedure to optimize cDNA synthesis, and increasing the annealing temperature for primers. With this approach, the HCV-1 genome (nucleotides 35-9282) was amplified consistently as two overlapping fragments of 5344 and 4675 bp from a pooled chimpanzee plasma sample containing approximately 10(6) genome copies of HCV RNA/ml. Using the conditions that we identified, 96% of the complete genomic sequence of a distinct HCV genotype 6 variant (km45) was determined from less than 300 microl of serum. This method should prove useful for molecular, epidemiological and clinical studies of hepatitis C where samples are limited but complete virus sequence is required, for example, identifying mutational hot spots of HCV under specific clinical conditions.

Genotype distribution and molecular epidemiology of hepatitis C virus in blood donors from southeast France

The genotype distribution of hepatitis C virus (HCV) in blood donors from southeast France was tracked for a period of 13 years (1991 to 2003). Virus genomes from 321 samples were analyzed by amplification and sequencing of the NS5b and E1 regions. The most frequent genotypes were 1b (30.2%), 1a (27.7%), and 3a (22.4%). Although it was less common, genotype 2 was characterized by the presence of strains belonging to 11 different subtypes, including 5 that had never been characterized. Genotypes 1a, 1b, 3a, and 4a presented typical "epidemic" profiles, with a large number of isolates per subtype and short mean genetic distances between isolates. Type 2 isolates displayed a typical "endemic" profile, with a large number of subtypes and very few isolates in each subtype. The epidemiology of HCV infection in southeast France changed radically during the study period in relation to modifications in the etiology of infection. We observed the emergence of new epidemic subtypes (subtypes 1a and 3) linked to intravenous drug use and a decrease in the types linked to blood transfusion and nosocomial infection (epidemic subtype 1b and endemic type 2). Comparison of strains from blood donors with strains from a cohort of inpatients in the same region during 2001 and 2002 demonstrated for the first time that the monitoring of blood donors is a generally valid indicator of HCV epidemiology in terms of genotype distribution.

An in vitro model of hepatitis C virus genotype 3a-associated triglycerides accumulation

BACKGROUND/AIMS

The hepatitis C virus (HCV) induces lipid accumulation in vitro and in vivo. Although clinical observations are consistent with a direct effect of HCV genotype 3a on lipid metabolism, experimental systems have focused on the expression of HCV proteins of genotype 1. To extend these observations, we established an in vitro model expressing the HCV core of different genotypes.

METHODS

The HCV core protein from patients with severe (genotype 3a) or no (genotypes 1b, 2a, 3h, 4h and 5a) liver steatosis was expressed in Huh7 cells. Core protein expression (by immunohistochemistry and immunoblot) and triglycerides accumulation (by Oil Red O stain and enzymatic measurement) were evaluated 48h after transfection.

RESULTS

Although triglyceride accumulation occurred with genotypes 1b, 3a and 3h, the genotype 3a core protein expression resulted in the highest level of accumulation (i.e. about 3-fold with respect to 1b, and 2-fold with respect to 3h). This effect was not related to core protein expression levels and was abolished by culturing cells in lipid-free medium.

CONCLUSIONS

Consistent with observations in chronic hepatitis C patients, the in vitro expression of HCV genotype 3a core protein is the ideal candidate model for studying the mechanisms of HCV-associated steatosis.

Hepatitis C virus subtyping by a core-envelope 1-based reverse transcriptase PCR assay with sequencing and its use in determining subtype distribution among Danish patients

A reverse transcriptase PCR (RT-PCR) assay using conserved primers deduced from the core-envelope 1 (C-E1) region of the hepatitis C virus (HCV) genome was developed for subtyping purposes. The sensitivity and specificity of this assay tested against two HCV reference panels containing genotype 1 through 5 subtypes were similar to those of an RT-PCR assay from the 5'-untranslated region (5'-UTR). The sensitivity of the RT-PCR typing assay in the more variable C-E1 region was, however, lower than that of the RT-PCR in the highly conserved 5'-UTR when testing multiple clinical samples. Thus, 71 (88%) of 81 consecutive samples from hospitalized Danish patients positive for HCV antibodies and RNA (5'-UTR) were positive also in the C-E1 RT-PCR assay. Phylogenetic analysis of the E1 sequences obtained by direct sequencing of HCV from two reference panels and 71 Danish patients allowed us to readily distinguish the subtypes. In contrast, phylogenetic analysis of their corresponding 5'-UTR sequences was able to predict only major genotypes. Three different genotypes and four subtypes were identified among Danish samples: 1a (43%), 1b (11%), 2b (6%), and 3a (39%). An isolate from a Somalian refugee was identified as a new HCV type related to Somalian isolates described as subtype 3h. The most common genotype in Denmark is genotype 1 (53%), which is the most difficult to treat. However, Denmark had the highest prevalence in Europe of subtype 3a, which responds more favorably to treatment. The described C-E1 RT-PCR with sequencing is suggested as an easy routine assay for definitive genotyping and subtyping of HCV.

Molecular evidence that the hepatitis C virus replicates in the oral mucosa

BACKGROUND/AIMS

Patients infected with the hepatitis C virus (HCV) often have extrahepatic manifestations, which significantly contribute to HCV-related morbidity, but whose pathogenesis is largely unknown. Our aim was to evaluate the HCV replication in oral mucosa of chronic hepatitis C patients.

METHODS

We collected oral mucosa specimens from 17 anti-HCV-positive and four anti-HCV-negative patients. Fifteen had oral lichen (12 anti-HCV-positive). Total mucosa RNA was extracted and analyzed for presence and titer of genomic and negative-strand HCV RNA. Findings were compared with clinical and pathological features.

RESULTS

Genomic and negative-strand HCV RNA were detected, respectively, in 12 of 17 (70.6%) and four of 17 (23.5%) specimens from the chronic hepatitis C patients. No negative-strand HCV RNA was detected in five anti-HCV-positive patients without lichen (including three with normal mucosa). Presence and titer of the negative-strand HCV RNA were independent of HCV genotype, serum viral load, and histological diagnosis of liver lesions. The phylogenetic analysis of the envelope 2 region cloned from a normal mucosa and the corresponding serum further suggested that only lichen tissues appear to harbor replicating HCV.

CONCLUSIONS

HCV may occasionally replicate in oral lichen tissue, possibly contributing to the pathogenesis of mucosa damage.