Mechanisms of porcine diarrheal disease

Abstract

JAVMA, Vol 231, No. 1, July 1, 2007 E disease continues to be a substantial problem in the swine industry, contributing to poor growth performance, increased morbidity and mortality rates, compromised welfare, and economic losses. Advances in the understanding of swine management, vaccine technology, and prophylactic antimicrobial regimens have substantially reduced the impact of certain diarrheal diseases of swine, but several pathogens continue to pose major challenges to the swine industry. Intensive management practices and changes in genetics have likely led to increased susceptibility of pigs to common enteric pathogens and the emergence of new pathogens that were once considered commensal. Several of these pathogens have not been fully characterized, or their pathophysiologic features are not well understood. Since a review of the mechanisms of diarrhea by Moon in 1978, the basic understanding of pathophysiologic mechanisms of diarrheal disease has increased considerably. Elucidation of the molecular basics of intestinal ion transport and how these molecular events become dysregulated by enteric pathogens have not only helped us better understand the disease process, but have also provided us with important information aiding in the development of diagnostic, management, and therapeutic strategies to combat these disorders. The objective of this report was to review the current understanding of the basic mechanisms of diarrheal diseases in swine, with particular emphasis on the ability of specific enteric pathogens to alter intestinal ion transport and fluid movement across intestinal epithelium. Although this review is focused on enteric diseases in pigs, basic mechanisms discussed apply to all veterinary species.