Phylogenetic characterization of genotype 4 hepatitis C virus isolates from Argentina

Genotyping of HCV RNA reveals that 3a is the most prevalent genotype in mardan, pakistan

The clinical outcomes of patients infected with hepatitis C virus (HCV) range from acute resolving hepatitis to chronic liver diseases such as liver cirrhosis or hepatocellular carcinoma. Identification of the infecting virus genotype is indispensable for the exploration of many aspects of HCV infection, including epidemiology, pathogenesis, and response to antiviral therapy. 1419 individuals were screened for anti-HCV in this study, of which 166 (11.7%) were found reactive by ICT (Immunochromatographic test). These 166 anti-HCV positive and 26 normal individuals were further analyzed. RNA was extracted from serum and reverse-transcribed to cDNA and the core region of HCV genome was targeted and amplified by multiplex PCR. HCV RNA was detected in 121 individuals, of which 87 were male and 34 were female. Genotype 3a was the most prevalent among all the genotypes observed followed by 3b. Genotypes 1a, 2a, and 2b were found in 10.89%, 13.22%, and 6.61% patients, respectively. 25.41% of the HCV RNA positive samples were not typed. 6.05% of patients were found having mixed genotypes. These findings will not only help the physicians to prescribe more appropriate treatment for the HCV infection but will also draw the attention of health-related policy makers to devise strategies to curb the disease more effectively.

Molecular epidemiology and putative origin of hepatitis C virus in random volunteers from Argentina

AIM: To study the subtype prevalence and the phylogenetic relatedness of hepatitis C virus (HCV) sequences obtained from the Argentine general population, a large cohort of individuals was analyzed.

METHODS: Healthy Argentinian volunteers (n = 6251) from 12 provinces representing all geographical regions of the country were studied. All parents or legal guardians of individuals younger than 18 years provided informed written consent for participation. The corresponding written permission from all municipal authorities was obtained from each city or town where subjects were to be included. HCV RNA reverse transcription-polymerase chain reaction products were sequenced and phylogenetically analyzed. The 5’ untranslated region (5’UTR) was used for RNA detection and initial genotype classification. The NS5B polymerase region, encompassing nt 8262-8610, was used for subtyping.

RESULTS: An unexpectedly low prevalence of HCV infection in the general population (0.32%) was observed. Our data contrasted with previous studies that reported rates ranging from 1.5% to 2.5%, mainly performed in selected populations of blood donors or vulnerable groups. The latter values are in keeping with the prevalence reported by the 2007 Argentinian HCV Consensus (approximately 2%). HCV subtypes were distributed as follows: 1a (25%), 1b (25%), 2c (25%), 3a (5%), and 2j (5%). Two isolates ascribed either to genotype 1 (5%) or to genotype 3 (5%) by 5’UTR phylogenetic analysis could not be subtyped. Subtype 1a sequences comprised a highly homogeneous population and clustered with United States sequences. Genotype 1b sequences represented a heterogeneous population, suggesting that this genotype might have been introduced from different sources. Most subtype 2c sequences clustered close to the 2c reported from Italy and Southern France.

CONCLUSION: HCV has a low prevalence of 0.32% in the studied general population of Argentina. The pattern of HCV introduction and transmission in Argentina appears to be a consequence of multiple events and different for each subtype.

An overview about hepatitis C: a devastating virus

Hepatitis C (HCV) is the disease that has affected around 200 million people globally. HCV is a life threatening human pathogen, not only because of its high prevalence and worldwide burden but also because of the potentially serious complications of persistent HCV infection. Chronicity of the disease leads to cirrhosis, hepatocellular carcinoma and end-stage liver disease. HCV positive hepatocytes vary between less than 5% and up to 100%, indicating the high rate of replication of viral RNA. HCV has a very high mutational rate that enables it to escape the immune system. Viral diversity has two levels; the genotypes and Quasiaspecies. Major HCV genotypes constitute genotype 1, 2, 3, 4, 5 and 6 while more than 50 subtypes are known. All HCV genotypes have their particular patterns of geographical distribution and a slight drift in viral population has been observed in some parts of the globe.

High prevalence of infection with a single hepatitis C virus genotype in a small rural community of Argentina

BACKGROUND

During the years preceding this study, we noticed a relatively unusual high number of individuals with elevated alanine aminotransferase (ALT) levels in O'Brien, a small rural town in Argentina. Moreover, four individuals from this town underwent liver transplantation owing to hepatitis C virus (HCV)-induced liver cirrhosis. These findings prompted us to conduct a large population-based survey to evaluate the prevalence of HCV in this community.

METHODS AND RESULTS

A total of 1637 individuals were studied. The overall HCV-seroprevalence was 5.7% (93/1637), being slightly higher in men (45/769; 5.9%) than in women (48/868; 5.5%). HCV seroprevalence increased with age, reaching a peak rate of 23.9% among individuals between 61 and 70 years of age. HCV RNA was present in 82.7% of all HCV seropositive individuals identified and 100% of them were infected with genotype 1b. ALT elevations were detected in 44% of HCV+ patients and were only observed among viremic individuals. Hepatitis B virus infection was also prevalent (52%) among HCV-seropositive patients. The most common risk factor associated with HCV transmission identified was the apparent use of inadequately sterilized glass syringes by a health care provider serving the community; however, other risk factors may have also played a role in the dissemination of HCV.

CONCLUSIONS

Our findings provide an explanation for the relative high number of individuals with elevated ALT levels observed in this community and form the basis of future prospective studies on the natural history of genotype 1b infection.

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.

Hepatitis C virus infection in infants and children from Argentina

Hepatitis C virus (HCV) infection is uncommon in children, and its natural history is still unknown. Our aim was to analyze exposure to HCV in 48 infants and children in Argentina and to evaluate consecutive samples in 26 of them to study the outcome of HCV infection in early stages. HCV viremia, as determined by reverse transcription-PCR (RT-PCR) from the 5' untranslated region, showed continuously positive, occasionally positive, and negative patterns during follow-up. Restriction fragment length polymorphism was performed on RT-PCR-positive samples to evaluate HCV genotype. Genotype 1 turned out to be predominant, and no patient displayed a genotype shift during the observation period. Perinatal HCV infection was predominantly observed in patients born to mothers coinfected with HCV and human immunodeficiency virus. HCV viral load was detected by means of the AMPLICOR MONITOR, version 2.0, kit. No correlation was observed between HCV viral load and alanine aminotransferase and aspartate aminotransferase levels, although we detected a trend towards higher levels among patients displaying consecutive positive HCV RT-PCR results. Our results demonstrate that pediatric HCV infection is characterized by high viral loads and diverse HCV viremia patterns, independent of both age and route of transmission in the population under study. Further research is necessary to determine whether the high rate of HCV replication is related to virus variability or to host immune response.

Hepatitis C virus isolates from Argentina disclose a novel genotype 1-associated restriction pattern

Hepatitis C virus isolates which disclosed a novel genotype 1-associated restriction pattern by restriction fragment length polymorphism analysis were characterized. Except for a mother and child pair, the patients were unrelated. Sequence analysis showed a G-->A substitution leading to a new RsaI recognition site. Phylogenetic analysis revealed that these isolates constitute a novel genetic lineage within the main cluster of genotype 1 strains.

Evolutionary study of HVR1 of E2 in chronic hepatitis C virus infection

Hypervariable region 1 (HVR1) of the hepatitis C virus (HCV) genome was directly sequenced from 12 chronically infected patients who had not responded to interferon (IFN) treatment. Due to the quasispecies nature of HCV circulating genomes, serum samples from four patients showing different evolutionary characteristics were further analysed. Serial samples from each patient were taken before, soon after and 14-23 months after a 6 month IFN treatment. HVR1 from each sample was amplified, cloned and the clones sequenced. For each patient, a phylogenetic analysis of the clones was performed and quasispecies complexity and genetic distances were calculated. The amino acid sequences and predicted antigenic profiles were analysed. The pre-treatment samples of the different patients presented dissimilar genetic quasispecies composition. For three of the patients, we showed that, regardless of the complexity or diversity of the viral populations before treatment, they evolved towards genetic diversification following selective pressure. Once the environment became stable, the entire population tended towards homogeneity. The fourth patient represented a case where different components of the quasispecies coexisted for long periods without replacement. We propose herein that the evolution of HVR1 of E2 is more likely to be directed by selection of clearly different subpopulations (modification of quasispecies equilibrium) than by a continuous mechanism related to the successive accumulation of point mutations. The prevalence of a quasispecies shift mechanism was revealed by the cloning analysis during the follow-up period of the evolutionary process.