The First Complete Genome Sequences of Hepatitis C Virus Subtype 2b from Latin America: Molecular Characterization and Phylogeographic Analysis

The hepatitis C virus (HCV) has remarkable genetic diversity and exists as eight genotypes (1 to 8) with distinct geographic distributions. No complete genome sequence of HCV subtype 2b (HCV-2b) is available from Latin American countries, and the factors underlying its emergence and spread within the continent remain unknown. The present study was conducted to determine the first full-length genomic sequences of HCV-2b isolates from Latin America and reconstruct the spatial and temporal diversification of this subtype in Brazil. Nearly complete HCV-2b genomes isolated from two Brazilian patients were obtained by direct sequencing of long PCR fragments and analyzed together with reference sequences using the Bayesian coalescent and phylogeographic framework approaches. The two HCV-2b genomes were 9318 nucleotides (nt) in length (nt 37-9354). Interestingly, the long RT-PCR technique was able to detect co-circulation of viral variants that contained an in-frame deletion of 2022 nt encompassing E1, E2, and p7 proteins. Spatiotemporal reconstruction analyses suggest that HCV-2b had a single introduction in Brazil during the early 1980s, displaying an epidemic history characterized by a low and virtually constant population size until the present time. These results coincide with epidemiological data in Brazil and may explain the low national prevalence of this subtype.

Detection of HCV genome in peripheral blood mononuclear cells of Iranian seropositive and HCV RNA negative in plasma of patients with beta-thalassemia major: Occult HCV infection

Beta (β) thalassemia major is a genetic blood disorder with a deficiency in the hemoglobin beta chain, requiring blood transfusion therapy. Multiple blood transfusions increase the risk of transmitting blood-borne infections. The aim of this study is to determine the frequency of hepatitis C virus (HCV) infection in Iranian individuals with β-thalassemia major. A total of 164 patients with β-thalassemia major were recruited for this study. HCV RNA testing was done on plasma and peripheral blood mononuclear cells (PBMCs) from the HCV seropositive samples (with reverse transcriptase-nested polymerase chain reaction [PCR] method using primers from the 5'-untranslated region [UTR]), and all HCV RNA positive samples were genotyped by the restriction fragment length polymorphism assay. For confirmation of the HCV genotyping in PBMCs of occult HCV infection [OCI]-positive patients, the PCR products of two different regions of HCV (5'-UTR and nonstructural protein 5B [NS5B]) were sequenced. Of 164 patients, 29.3% were positive for anti-HCV antibodies, and HCV RNA was detected in the plasma specimens of 13.4% patients and in the PBMC samples of 15.2% participants. The genomic HCV-RNA was detected in PBMC samples in 3 (6.3%) of the total 48 individuals who were HCV seropositive, and plasma HCV-RNA negative (occult HCV infection). The subtypes of HCV in the plasma and PBMC samples of three participants were not identical. This study shows that among this group of Iranian patients with β-thalassemia major, 13.4% had active HCV infection and 6.3% had occult HCV infection as evidenced by HCV RNA detected in PBMC specimens. Therefore, the design of a prospective study that focuses on the diagnosis of OCI can be very valuable and provide more information.

Population dynamics of hepatitis C virus subtypes in injecting drug users on methadone maintenance treatment in China associated with economic and health reform

The extensive genetic heterogeneity of hepatitis C virus (HCV) requires in-depth understanding of the population dynamics of different viral subtypes for more effective control of epidemic outbreaks. We analysed HCV sequences data from 125 participants in Wuhan, China. These participants were newly infected by subtype 1b (n=13), 3a (n=15), 3b (n=50) and 6a (n=39) while on methadone maintenance treatment (MMT). Bayesian phylogenies and demographic histories were inferred for these subtypes. Participants infected with HCV-1b and 3a were clustered in well-supported monophyletic clades, indicating local subepidemics. Subtypes 3b and 6a strains were intermixed with other Chinese isolates, as well as isolates from other Asian countries, reflecting ongoing across geographic boundary transmissions. Subtypes 1b and 3a declined continuously during the past ten years, consistent with the health and economic reform in China, while subtype 3b showed ongoing exponential growth and 6a was characterized by several epidemic waves, possibly related to the recently growing number of travellers between China and other Asian countries. In conclusion, results of this study suggest that HCV subtype 3b and 6a subepidemics in China are currently not under control, and new epidemic waves may emerge given the rapid increase in international travelling following substantial economic growth.