New infection with heterotypic hepatitis C virus in a patient with long-term hepatitis C virus eradication

Molecular and contextual markers of hepatitis C virus and drug abuse

The spread of hepatitis C virus (HCV) infection involves a complex interplay of social risks, and molecular factors of both virus and host. Injection drug abuse is the most powerful risk factor for HCV infection, followed by sexual transmission and additional non-injection drug abuse factors such as co-infection with other viruses and barriers to treatment. It is clearly important to understand the wider context in which the factors related to HCV infection occur. This understanding is required for a comprehensive approach leading to the successful prevention, diagnosis, and treatment of HCV. An additional consideration is that current treatments and advanced molecular methods are generally unavailable to socially disadvantaged patients. Thus, the recognition of behavioral/social, viral, and host factors as components of an integrated approach to HCV is important to help this vulnerable group. Equally important, this approach is key to the development of personalized patient treatment - a significant goal in global healthcare. In this review, we discuss recent findings concerning the impact of drug abuse, epidemiology, social behavior, virology, immunopathology, and genetics on HCV infection and the course of disease.

Hepatitis C virus infection and injection drug users: prevention, risk factors, and treatment

Injection drug users (IDUs) are the largest group of persons infected with hepatitis C virus (HCV), with a prevalence of 50%-90%. The transmission of HCV is not the effect of the drug injected but of sharing contaminated equipment. For the sake of prevention, we have to know which factors are more likely to lead to HCV seroconversion and which particular situations and environments are risk factors for equipment sharing. As far as therapy is concerned, some studies have shown that treatment for HCV infection in IDUs during substitution treatment for drug dependency is as successful as is treatment of patients who are not IDUs. Screening and early treatment of IDUs could play an important role in controlling HCV infection. The rate of reinfection may not as high as supposed. All studies dealing with treatment for HCV infection in IDUs have stressed the necessity of collaboration among hepatologists and specialists in addiction medicine, social workers, and psychotherapists.

Infrequent reinfection after successful treatment for hepatitis C virus infection in injection drug users

We followed-up 18 injection drug users for a mean of 33.8 months (range, 4-55 months) after successful treatment for hepatitis C virus (HCV) infection. Fifteen (83%) of the patients remained HCV RNA-negative, 1 patient was not tested, and 2 patients had test results positive for HCV RNA. The estimated rate of reinfection as a result of injection drug use was 0-4.1 cases per 100 person-years (cumulative incidence, 0%-12.6% at 48 months after completion of treatment). Of 50 patients originally treated, 15 (30%) were HCV RNA-negative 3 years later.

Hepatitis C virus replication kinetics in chimpanzees with self-limited and chronic infections

The availability of molecular beacon-based, real time polymerase chain reaction (PCR) and a semi-automated sample extraction procedure have made it possible for us to retrospectively examine HCV replication kinetics in HCV naive chimpanzees infected during the past 20 years. We compared these in 17 animals that developed chronic infection, and in 21 that developed self-limited infection. No differences were found in infecting dose, or replication kinetics in the acute phase between these two types of infection. An unanticipated finding was the fact that 10 of 17 animals developing chronic infection partially controlled virus replication for 48 +/- 48 weeks after typical acute phase viraemia, and prior to development of chronic infection. Twenty-nine out of 30 (29/30) sera, which were negative by quantitative PCR during the downregulated period, were, however, positive by the more sensitive Genprobe isothermal transcription-mediated amplification (TMA) assay. Thus, downregulation was not complete. Ten animals showing self-limited infection showed complete resolution of viraemia by TMA assay. Quasispecies analysis revealed that in all, except one case, the virus reappearing after downregulation was essentially identical to that of the originally infecting virus.