Corynebacterium equi enteritis in foals.

The research article discusses two cases of intestinal damage in foals, caused by the bacterium Corynebacterium equi, which is typically associated with respiratory diseases.

Study Objective and Background

• The main objective of the study was to investigate the unusual manifestation of Corynebacterium equi infection in foals. Instead of respiratory disease, in these cases, the foals experienced significant intestinal damage.
• Corynebacterium equi is a bacteria pathogen often linked to respiratory disease in foals, but in two reported cases, it appeared to have a different effect, causing acute and chronic intestinal conditions.

Findings and Observation

• In both foals, the only observable lesion in the small intestine was necrosis of Peyer’s patches. Peyer’s patches are part of the immune system found in the small intestine.
• Each foal showed distinct symptoms and damage to the large intestine. The foal with acute disease had noticeable green-tan focal necrosis and thickened mucosa, while in the chronic case, the mucosa was thickened, rugose (wrinkled) and had a mottled red-tan appearance.
• Further analysis of the tissue showed villous atrophy (shrinking of finger-like projections in the intestine), mucosal necrosis (cell death in the lining of the intestine), mesenteric lymph node necrosis (cell death in a type of immune cell), and a large number of immune cells known as macrophages, which were filled with gram-positive pleomorphic bacilli, a type of bacteria.

Further Investigation

• In addition to histological examination, electron microscopy of the intestinal mucosa revealed binary fission (a type of asexual reproduction) in macrophages, as well as free bacilli in the lamina propria (a layer of loose connective tissue found below the epithelium of organs, including the intestines).
• The findings suggest that Corynebacterium equi can cause severe intestinal damage in foals, beyond its traditional association with respiratory diseases.
• The study provides new evidence for understanding the range of diseases associated with Corynebacterium equi infection in foals and suggests further research is needed to fully understand the disease mechanism.