Validation of an ileitis mucosal homogenate seeder pig model to study the natural transmission oiLawsonia intracellularis in grow-finish pigs

摘要

Ileitis or PPE (Porcine Proliferative Enteropathy) or Lawsonia intracellularis is considered the most common grow-finish enteric disease of North American swine. There are three forms of the disease: (1) acute (PHE-Porcine Hemorrhagic Enteropathy), (2) chronic (PIA-Porcine Intestinal Adenomatosis), and (3) subclinical. The subclinical form is by far the most prevalent. Ileitis mucosal homogenate challenge models have been used to test antibiotic efficacy since the mid-90's.' The classic FDA approvedileitis challenge model is given to 4-6 week old pigs at a 109 dose per pig to consistently cause 3-10% ileitis mortality and significant clinical signs of gauntness and/or diarrhea in about 80% of the control pigs.' Pigs challenged at older ages of 10-20 weeks do not reproduce similar clinical signs, with the majority of pigs being subclinical. However, performance loss and ileitis positive diagnostics are still very evident in these subclinical carrier pigs. Since the majority of ileitis occurs in the grow-finish pig and transmits naturally through a population, a mucosal homogenate seeder pig model given to 10 week old pigs was evaluated in this study.