Hepatitis C virus (HCV) is a leading cause of liver cancer and cirrhosis, and Egypt has possibly the highest HCV prevalence worldwide. In this article we use a newly developed Bayesian inference framework to estimate the transmission dynamics of HCV in Egypt from sampled viral gene sequences, and to predict the public health impact of the virus. Our results indicate that the effective number of HCV infections in Egypt underwent rapid exponential growth between 1930 and 1955. The timing and speed of this spread provides quantitative genetic evidence that the Egyptian HCV epidemic was initiated and propagated by extensive antischistosomiasis injection campaigns. Although our results show that HCV transmission has since decreased, we conclude that HCV is likely to remain prevalent in Egypt for several decades. Our combined population genetic and epidemiological analysis provides detailed estimates of historical changes in Egyptian HCV prevalence. Because our results are consistent with a demographic scenario specified a priori, they also provide an objective test of inference methods based on the coalescent process.

Hepatitis B virus (HBV) is classified into genotypes A^F, which is important for clinical and etiological investigations. To establish a simple genotyping method, 68 full-genomic sequences and 106 S gene sequences were analyzed by the molecular evolutionary method. HBV genotyping with the S gene sequence is consistent with genetic analysis using the fullgenomic sequence. After alignment of the S sequences, genotype specific regions are identified and digested by the restriction enzymes, HphI, NciI, AlwI, EarI, and NlaIV. This HBV genotyping system using restriction fragment length polymorphism (RFLP) was confirmed to be correct when the PCR products of the S gene in 23 isolates collected from various countries were digested with this method. A restriction site for EarI in genotype B was absent in spite of its presence in all the other genotypes and genotype C has no restriction site for AlwI.Only genotype E is digested with NciI, while only genotype F has a restriction site for HphI. Genotype A can be distinguished by a single restriction enzyme site for NlaIV, while genotype D digestion with this enzyme results in two products that migrates at 265 and 186 bp. This simple and accurate HBV genotyping system using RFLP is considered to be useful for research on HBV.z 1999 Federation of European Biochemical Societies.

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.

Background: The response rates and duration of peginterferon alpha (PEG-IFN-a) and ribavirin combination therapy in chronic hepatitis C genotype 4, the prevalent genotype in the Middle East and Africa, are poorly documented. Aims: To compare the efficacy and safety of 24, 36, or 48 weeks of PEG-IFN-a-2b and ribavirin therapy in chronic hepatitis C genotype 4. Methods: In this prospective, randomised, double blind study, 287 patients with chronic hepatitis C genotype 4 were randomly assigned to PEG-IFN-a-2b (1.5 mg/kg) once weekly plus daily ribavirin (1000-1200 mg) for 24 weeks (group A, n = 95), 36 weeks (group B, n = 96), or 48 weeks (group C, n = 96) and followed for 48 weeks after completion of treatment. Early viral kinetics and histopathological evaluation of pre-and post treatment liver biopsies were performed. The primary end point was viral clearance 48 weeks after completion of treatment. Results: Sustained virological response was achieved in 29%, 66%, and 69% of patients treated with PEG-IFN-a-2b and ribavirin for 24, 36, and 48 weeks, respectively, by intention to treat analysis. No statistically significant difference in sustained virological response rates was detected between 36 and 48 weeks of therapy (p = 0.3). Subjects with sustained virological response showed greater antiviral efficacy (e) and rapid viral load decline from baseline to treatment week 4 compared with non-responders and improvement in liver histology. The incidence of adverse events was higher in the group treated for 48 weeks. Conclusion: PEG-IFN-a-2b and ribavirin for 36 or 48 weeks was more effective in the treatment of chronic hepatitis C genotype 4 than treatment for 24 weeks. Thirty six week therapy was well tolerated and produced sustained virological and histological response rates similar to the 48 week regimen.

A phylogenetic analysis, using the open reading frame I sequence of 93 TT viruses (TTV) obtained from various geographical areas, indicated that the virus could be classified into six different genotypes including three hitherto unreported genotypes. The high reliability of the six clusters was confirmed by bootstrap analysis. On the basis of these sequence data, a new simple genotyping assay based on a restriction fragment length polymorphism of TTV was developed. Using the enzymes NdeI and PstI, followed by cleavage with NlaIII or MseI, it was possible to distinguish between the six TTV genotypes. This system will provide the framework for future detailed epidemiological and clinical investigations.