Immunology of inflammatory diseases of the bowel.

During the past century, research on animal diseases has focused on the characterization of specific etiologies and disease control strategies. Many diseases affecting domestic animals have been successfully controlled using various methods, including vaccination, management, vector control, or antimicrobial agents. A number of microorganisms have proven resistant to these efforts. Control of these organisms requires the development of new strategies. As practitioners and researchers, we need to consider approaches that encompass the entire realm of disease expression from molecular to immune responses and interactions with other functional systems (e.g., endocrine, neurologic, and vascular systems). We need a basic understanding of effective immune responses enabling the tailoring of vaccines to produce the desired response. This tailoring of host responses is augmented by the use of vaccines that use host growth factors, cytokines, or costimulatory molecules to bias the ensuing response. Intestinal microbial flora of food-producing animals can be managed to optimize health and minimize colonization by pathogenic organisms, especially zoonotic agents. New systems for the delivery of cytokines and other factors that favor optimal intestinal health and homeostasis need to be researched and evaluated. With time, it is likely that our clients and the consumers will be less tolerant of antibiotic usage. They will be more aware of the zoonotic potential of many microbes that colonize food animals. Food safety issues will be a continuing concern, as will the protection of our water supply from contamination from feedlots and pasture runoff. We are in the dawn of a new century, and, it is hoped, a new era of discovery of enteric disease pathogenesis and control.