This course introduces the fundamental mechanisms by which microbes interact with their hosts, spanning relationships that lead to both pathogenesis and mutulism. Students will explore microbial strategies for colonization, immune evasion, and disease causation, as well as beneficial interactions that support host health, development, and ecosystem function. Emphasis is placed on molecular, cellular, and ecological perspectives of host-microbe interactions, preparing students to understand how these processes shape outcomes in human, animal, and environmental contexts. Completing MICR 470/670 recommended. Dual-listing: MICR 450.