Alter MJ. Mast EE. Moyer LA. Margolis HS.
Division of Viral and Rickettsial Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, Georgia, USA.
Hepatitis C virus (HCV) has emerged as a major cause of chronic liver disease worldwide. The widespread endemicity of HCV infection is the result of a combination of factors, including those related to the genetic diversity of the virus and the host response and those related to the specific settings and behaviors that have facilitated transmission. Most people who contract HCV infection become persistently infected, and the mechanism by which persistent infection is established seems to be related to the lack of development of an effective neutralizing immune response. The magnitude of the spread of HCV infection primarily is related to specific risk factors for transmission. The most important human behavior related to the transmission of HCV has been injection drug use, which in many developed countries has been the leading source of HCV infection during the past 20 to 30 years. The recognition of the clinical importance of HCV infection has resulted in a substantial amount of attention and resources rapidly directed toward developing new and improved therapies. The perception, however, of the public health importance of HCV infection is still limited. Despite the knowledge that injection drug use is the major source of HCV infection in the United States, this message has not been included in prevention and treatment programs, and the resources needed to support strong public health programs have yet to be identified.
Division of Infectious Diseases and Geographic Medicine, Stanford University School of Medicine, California, USA.
Helicobacter pylori infection causes peptic ulcer disease, gastric adenocarcinoma, gastric lymphoma, and probably nonulcer dyspepsia. Although the prevalence of infection is declining over time, the organism still infects approximately one half of the world's population. Only a minority will ever suffer serious consequences from their infection. This article reviews current knowledge about H. pylori and presents some of the dilemmas surrounding clinical and public health approaches to this widespread pathogen.