Cover photograph (Copyright © 2015, American Society for Microbiology. All Rights Reserved.): Infiltration of F4/80-positive (red) macrophages in liver of Sv129S6 mouse following oral infection with Salmonella enterica serovar Typhimurium. The image shows increased F4/80-positive (red) liver sinusoidal macrophages (Kupffer cells) at 3 weeks postinfection (×50 original magnification). The arrow indicates an F4/80-positive sinusoidal hemophagocytic macrophage in the infected liver. (See related article on page 2290.)