Trichomonads and Brachyspira murdochii infection in pigs with colitis

Published: December 12, 2024

By: M. Culhane 1, F. Giannitti 2, C. Gebhart 3, J. Sarradell 4, K. Sverlow 5 / 1 Veterinary Population Medicine Department, University of Minnesota College of Veterinary Medicine; 2 Veterinary Diagnostic Laboratory, University of Minnesota; 3 Veterinary Diagnostic Laboratory, University of Minnesota College of Veterinary Medicine, St. Paul, United States; 4 Facultad de Ciencias Veterinarias, Universidad Nacional de Rosario, Casilda, Santa Fe, Argentina; 5 California Animal Health and Food Safety Laboratory.

Summary

Keywords: colitis, diarrhea, trichomonads

Introduction:

Gastrointestinal disease is one of the leading causes of clinical signs in growing and finishing pigs. We herein describe several diagnostic cases of finisher pig colitis wherein both novel and common pathogens were discovered.

Materials and Methods:

Necropsies of 5 pigs, 10-13 weeks of age, with diarrhea and weight loss, were performed at two swine farms, each housing > 15,000 growing pigs. Tissue samples including colon were submitted to the UMN-VDL between 12/19/2014 and 1/9/2015.

Results:

Histologic examination of the colon in all cases revealed moderate (cases 1-4) to mild (case 5) proliferative colitis with intralesional trichomonads. Brachyspira murdochii was isolated from the colon and detected by immunohistochemistry in cases 3-5, but not in cases 1-2. Positive immunoreactivity for Trichomonas spp. in sections of colon was observed in cases 1-2 by immunohistochemistry, performed at UC-Davis. Trichomonas spp. were present in the lumen of dilated and hyperplastic mucosal glands, invading the lamina propria, and rarely in the cytoplasm of goblet cells and enterocytes. Trichomonads were also found within the cytoplasm of mucosal gland and proprial macrophages (phagocytosis), suggesting elicitation of an innate immune response.

Conclusion:

Common causes of colitis in pigs also include Lawsonia intracellularis and Salmonella enterica; however, they were not detected in these 5 index cases. Interestingly, L. intracellularis and/or Salmonella spp. were detected in the colons of several pigs submitted subsequently from both farms (data not shown).

Lesions in these pigs were consistent with an infectious colitis. Trichomonads infection with or without Brachyspira murdochii co-infection was diagnosed in all cases. Both agents have been considered facultative enteric pathogens in swine. Whether this co-infection was the inciting factor for the colitis is controversial. We speculate that the severity of colonic lesions induced is greater when both pathogens are present.

Disclosure of Interest: None Declared.

Published in the proceedings of the International Pig Veterinary Society Congress – IPVS2016. For information on the event, past and future editions, check out https://www.theipvs.com/future-congresses/.

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