Epsilon Archive for Student Projects

Abstract

Proliferative enteropathy is a group of disease conditions in pigs where the disease may vary from subclinical to critical with bloody loose feces. The etiological agent is the obligate intracellular bacteria Lawsonia intracellularis.
L. intracellularis infects enterocytes from jejunum to colon. The bacteria is taken into cells and start to replicate and cause a massive proliferation of immature enterocytes. There are several aspects in the pathogenesis of proliferative enteropathy that today remain unclear. As an example, it is not yet established how the bacteria invade cells. How the massive proliferation of enterocytes is induced after bacterial uptake into cells also remains unclear. It has been suggested that the uptake of bacteria could be a type of receptor mediated endocytosis and that the massive proliferation is the result of a bacterial regulation of cell differentiation- and/or apoptosis genes.
The different conditions are porcine intestinal adenomatosis/chronic proliferative enteropathy, proliferative hemorrhagic-/acute hemorrhagic enteropathy, necrotic enteritis and regional ileitis. In all conditions there is a thickening of the mucosa in the affected portion of the intestine due to a massive proliferation of immature enterocytes. In addition to this basic lesion additional changes are seen in proliferative hemorrhagic-/acute hemorrhagic enteropathy, necrotic enteritis and regional ileitis.
How L. intracellularis give rise to disease and how it induce the macroscopic lesions is still unknown and further research is therefore important.