Lawsonia

Proliferative enteropathy (PE), also known as ileitis, is an infectious disease caused by the obligate intracellular bacterium Lawsonia intracellularis. The disease is endemic in swine herds, and it is characterized by thickening of the intestinal mucosa due to intestinal crypt epithelial cell proliferation. Mild-to-severe diarrhea and weight loss are the major clinical signs observed in affected animals. Two major clinical forms of PE have been described: proliferative hemorrhagic enteropathy (PHE) and porcine intestinal adenomatosis (PIA). Economic losses due to PE have been associated with negative impacts on slaughter weight, feed conversion efficiency, space utilization, and an increase in the usage of antimicrobials. Diagnosis has primarily been based on clinical signs, proliferative lesions, and detection of L. intracellularis by polymerase chain reaction (PCR) or immunohistochemistry. In addition to antimicrobial therapy, vaccination has been the main strategy to prevent and reduce the clinical signs associated with L. intracellularis infection.