Genotypes of hepatitis C virus in Guangxi province, southern China

Changes in epidemiological patterns of HCV infection and their impact on liver disease over the last 20 years in Greece

The aim of this study was to investigate the relative frequency of hepatitis C virus (HCV) genotypes in Greek patients with chronic infection as well as possible secular changes in their distribution in relation to modes of transmission, age and time at acquisition of the infection and other variables. We evaluated 434 unselected patients, 241 males and 193 females with a median age of 46.2 years (18-75), with chronic HCV infection presenting during the period 1996-2000. HCV infection was confirmed by the detection of HCV-RNA by polymerase chain reaction (PCR), while HCV genotyping was performed by the Inno-LiPA assay. Liver biopsies were evaluated according to Ishak's scoring system. Of 434 patients, 167 had a history of blood transfusion [post-transfusion hepatitis (PTH)], 80 were i.v. drug users and in 187 the route of infection remained unknown. The overall distribution of HCV genotypes 1, 2, 3 and 4 was 47, 8.3, 27 and 15.2%, respectively. Genotype 3 was common in younger adults and i.v. drug users, whereas genotype 1 predominated in older people and PTH patients (P < 0.001 for both). Infection acquired before 1981 (group A) was related to transfusion and genotype 1, while after 1981 (group B) with i.v. drug use and genotype 3 (P < 0.01). Biopsy was available in 369 (85%) patients, of whom 22.5% had cirrhosis; 29.8% in group A and 9.9% in group B. In a multivariate analysis, cirrhosis was strongly associated with the duration of infection (P = 0.013). Our study revealed a change of HCV genotype distribution in the last 20 years among Greek patients with chronic HCV infection as a result of epidemiological changes in HCV transmission. The presence of cirrhosis was associated only with the duration of infection. These observations have impact both on prevention and treatment.

Hepatitis C virus genotype distribution in China: predominance of closely related subtype 1b isolates and existence of new genotype 6 variants

To determine hepatitis C virus (HCV) genotype distribution in China, a total of 148 HCV RNA positive serum samples were collected from nine geographic areas and subjected to RT-PCR followed by direct DNA sequencing and phylogenetic analysis of the core, E1, and NS5B regions. HCV was genotyped in 139 (93.9%) samples. Among them subtype 1b was the most predominant [66% (92/139)] followed by 2a [14% (19/139)]. Of 92 subtype 1b isolates, 35 (38%) and 30 (33%) formed two clusters, designated groups A and B. Group A was prevalent throughout China, while group B was predominant in the central and southern regions. In three cities in the Pearl River Delta, subtype 6a replaced 2a as the second most predominant subtype, and in Kunming (southwest) multiple HCV genotypes/subtypes were present. New variants of HCV genotype 6 were discovered in three samples from Kunming and one in Guangzhou in the Pearl River Delta.

Hepatitis C virus genetic variability: pathogenic and clinical implications

HCV is variable because of the properties of the viral RdRp, high levels of replication, and large population sizes. The Darwinian evolution of HCV has been characterized by the emergence of the HCV genotypes, including six main types and a large number of subtypes. The study of HCV genotype epidemiology provides useful information on the worldwide HCV epidemics. The HCV genotype is an important predictor of the response to IFN-alpha-based antiviral therapy, and genotype determination is currently used to tailor treatment indications. In addition, HCV circulates and behaves in infected individuals as mixtures of closely related but distinct viral populations referred to as quasispecies. This particular nature of the virus influences its transmission, the pathogenesis of liver disease and extra-hepatic manifestations, and the outcome during and after antiviral therapy or after transplantation for HCV-related end-stage liver disease. Further studies are needed to understand better the implications of HCV quasispecies diversity in the pathophysiology of HCV infection.

Hepatitis C virus seroconversion and genotype prevalence in patients and staff on chronic hemodialysis

The prevalence of hepatitis C virus (HCV)-RNA positivity among hemodialysis patients varies between 10 and 70%. Few previous surveys revealed high frequency of seroconversion of HCV-RNA-negative patients over the years of hemodialysis. Only few studies reported HCV genotype variability. We evaluated all 65 patients on chronic hemodialysis in our dialysis unit. All sera positive to anti-HCV on ELISA were retested by reverse transcriptase polymerase chain reaction to HCV-RNA. Sixteen patients were found anti-HCV positive on ELISA, and 8 of them were also PCR positive. Three of these eight patients seroconverted during the year 1995. Four patients had both 1a and 1b genotypes of HCV, coexistence of genotypes 1b and 4a in one patient and genotypes 1a, 1b and 2a in the remaining three patients. Mean serum aminotransferase, duration of dialysis, and number of blood units transfused were significantly higher in the HCV-PCR-positive patients compared with the HCV-PCR-negative patients. Because strict isolation methods were initiated at the end of 1995, not one new case of HCV among dialysis patients was found in 1998, although new hemodialysis patients were diagnosed as having HCV. In conclusion, genotypes 1a and 1b, as is true for the general population in Israel, were also the predominant genotypes among hemodialysis patients; the coexistence of more than one genotype is common among hemodialysis patients; seroconversion is common among these patients and strict isolation methods are efficient and should be recommended.