General Information: Lawsonia intracellularis PHE/MN1-00 was isolated from intestinal mucosal lesions in pigs that had proliferative enteropathy (PE). When introduced into health pigs, this organism produced the clinical and histological signs of PE. Causative agent for proliferative enteropathy in swine. This organism causes proliferative enteropathy (ileitis) in swine and other domesticated animals resulting in severe losses each year. This obligate intracellular pathogen infects the mucosa of the lower intestinal tract by initially infecting crypt cells, which are precursors that normally grow and divide in order to replace the epithelial cells. Once infection occurs, the crypt cells are stimulated to grow and divide abnormally, resulting in the proliferative phenotype. In severe cases of the disease the entire bowel can become affected and persist for up to 40 days, greatly affecting the host animal.