Equine Infectious Disease Research Laboratory

Lawsonia intracellularis

Equine proliferative enteropathy (EPE) is a disease of foals caused by the obligate intracellular organism Lawsonia intracellularis. This emerging disease affects mainly weanling foals and causes fever, lethargy, peripheral edema, diarrhea, colic and weight loss. The diagnosis of EPE may be challenging and relies on the presence of hypoproteinemia, thickening of segments of the small intestinal wall observed on abdominal ultrasonography, positive serology and molecular detection of L. intracellularis in feces. Although the clinical entity, diagnostic work-up and treatment of EPE are well established and described, the epidemiology for this disease has remained largely unaddressed. Our research group was initially involved with this disease in the epidemiological investigation of a sporadic case. This publication reported for the first time the potential role of domestic animals in the transmission of L. intracellularis to foals. This case set up a series of investigations aimed at further documenting the exposure rate of foals residing on endemic farms, the role of domestic and wild animals in the transmission of L. intracellularis to foals and the humoral immune response and fecal shedding in weanling foals following oral and intra-rectal administration of an avirulent live vaccine of L. intracellularis. The latest work represents an important contribution to the prevention of this debilitating disorder. Since no vaccines are labelled for use in the equine species, we use a commercially available swine product. With the support of Boehringer Ingelheim Vetmedica, the manufacturer of the avirulent live L. intracellularis vaccine, our laboratory has determined the safety and efficacy of this vaccine and also investigated alternative routes of vaccine administration. 

We are in the process of further investigating the use of this vaccine by refining the vaccine protocol and by determining the vaccine efficacy via experimental infection and field vaccine trails. Our laboratory is further investigating the epidemiology of this disease by pursuing potential candidate reservoir hosts and validating new diagnostic assays.

Review article (PDF)

PUSTERLA, N. and C. GEBHART. Equine Proliferative Enteropathy caused by Lawsonia intracellularis. Equine Vet. J. 21, 415-419.
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