Emerging Infections 4 is the fourth of an annual series of books based on ICAAC Symposia on Emerging Infections. It provides a complete and updated discussion of new and emerging infectious diseases, covering both basic science and clinical topics. The editors are in the forefront of the scientific and clinical communities dealing with emerging pathogens. This book and the series will be valuable to a wide range of people working in microbiology, infectious diseases, epidemiology, public health, and clinical medicine.