It is estimated that more than 500 million people throughout the world are infected with one of the six kinds of hepatitis viruses. Although hepatitis can be fatal, many people who are infected never show symptoms and don't realize they have the virus. This fact makes it easy for people to unknowingly spread the disease to others, especially through sexual contact. This book examines each of the six hepatitis viruses, focusing on how they cause infection, how they spread from one person to another, how they reproduce, and how our body's immune system tries to fight them. Also discussed are the ways that hepatitis-which has no cure-may be prevented or treated. Infectious diseases affect everyone. Although not all are fatal, each disease causes a degree of harm and discomfort to those that it afflicts, and can sometimes have long-lasting consequences. Each book in the series Deadly Diseases and Epidemics takes the reader through all aspects of infectious diseases-from the history of the disease and its method of infection, to its treatment and prevention. The books provide a foundation for understanding the basics of microbiology, immunology, and epidemiology.