Cover photograph (Copyright © 2005, American Society for Microbiology. All Rights Reserved.): Scanning electron micrograph of primary cultured rabbit tracheal epithelial cells following 5 min of coincubation with virulent wild-type Bordetella bronchiseptica. In this model for early host-pathogen interactions, wild-type B. bronchiseptica preferentially adheres to cilia and is rarely seen bound to aciliated cells or aciliated portions of ciliated cells. Bacteria have been pseudocolored pink for easier visualization. (Magnification, ×6,000.) (Special assistance on scanning electron microscopy by M. K. McCuskey is acknowledged.) (See related article on page 3618.)