Primary inflammatory alimentary diseases in equids can be categorized mainly by the anatomic location affected (eg, upper alimentary canal, stomach, and small and large intestines) or by the underlying cause (eg, mechanical, parasitic, toxic, and immune-mediated causes).1–5 Previous studies5–8 show that Salmonella spp and Clostridium difficile are the most important infectious causes of inflammation in the alimentary tract of equids, and such infections are mainly characterized clinically by colic and diarrhea and pathologically by enteritis, typhlitis, or colitis, alone or in combination. Other infectious agents (eg, Rhodococcus equi, Clostridium perfringens, rotavirus, and coronavirus) and parasites (eg, Strongylus spp) can also affect the digestive system of equids and cause enterocolitis, typhlitis, or both.8 In addition, toxicoses from toxins (eg, oleandrin [the toxic principle of Nerium oleander]4,9) or drugs (eg, NSAIDs8) can affect the digestive tract and result in ulcerative to severe inflammatory lesions.
Although the ability to determine the underlying cause of enteric diseases in equids has increased over time, mainly because of the implementation of more specific and sensitive diagnostic tools, the diagnosis of these conditions is still challenging.8 The difficulty is associated with the facts that different underlying causes, including etiologic agents, can result in similar clinical signs and lesions and that some of the etiologic agents can also be found in the intestines of clinically normal equids. Relatedly, the most common clinical sign of digestive disorders in horses is colic, which is defined as a gastrointestinal disease that causes signs of abdominal pain.10,11 The incidence of colic in horses in the United States has been reported12 as 4.2 events/100 horses/y, and colic is the second most common cause of death after old age. However, to our knowledge, neither the incidences of the inflammatory intestinal disturbances producing colic nor the main underlying causes of inflammatory gastrointestinal lesions are known for horses and other equids in California. Such knowledge would be useful to improve diagnostic and surveillance strategies for gastrointestinal diseases in horses and other equids. Therefore, the purpose of the study presented here was to determine the incidences and underlying causes of FIILs and the demographic characteristics of affected equids necropsied at any of the CAHFS facilities between January 1, 1990, and April 16, 2013.
This manuscript represents a portion of the thesis submitted by the senior author to the School of Veterinary Medicine, University of California-Davis, as partial fulfillment of the requirements for the Master of Preventive Veterinary Medicine degree.
Supported in part by the Consejo Nacional de Tecnología y Ciencia: “Becarios en el Extranjero,” the government of Mexico.
The authors declare that there were no conflicts of interest.
Presented in abstract form at the 56th Annual Meeting of the American Association of Veterinary Laboratory Diagnosticians, San Diego, October 2013.
The authors thank Dr. Santiago Diab for constructive criticism of the manuscript.
California Animal Health and Food Safety Laboratory
Fatal intestinal inflammatory lesion
SPSS Statistics, version 20, IMB Corp, Armonk, NY.
3. Cohen ND, Vontur CA, Rakestraw PC. Risk factors for enterolithiasis among horses in Texas. J Am Vet Med Assoc 2000;216:1787–1794.
4. Renier AC, Kass PH, Magdesian KG, et al. Oleander toxicosis in equids: 30 cases (1995–2010). J Am Vet Med Assoc 2013;242:540–549.
5. Uzal FA, Plattner BL, Hostetter JM. Alimentary system. In: Maxie, MG, ed. Jubb, Kennedy, Palmer's pathology of domestic animals. 6th ed. St Loius: Elsevier, 2016;69–128.
6. Ernst NS, Hernandez JA, MacKay RJ, et al. Risk factors associated with fecal Salmonella shedding among hospitalized horses with signs of gastrointestinal tract disease. J Am Vet Med Assoc 2004;225:275–281.
7. Diab SS, Songer G, Uzal FA. Clostridium difficile infection in horses: a review. Vet Microbiol 2013;167:42–49.
8. Uzal FA, Diab SS. Gastritis, enteritis, and colitis in horses. Vet Clin North Am Equine Pract 2015;31:337–358.
9. Galey FD, Holstege DM, Plumlee KH, et al. Diagnosis of oleander poisoning in livestock. J Vet Diagn Invest 1996;8:358–364.
10. Lavoie JP, Hinchcliff K. Colic in foals. In: Blackwell's five-minute veterinary consult: equine. 2nd ed. Ames, Iowa: Blackwell, 2007;192–193.
12. APHIS. Incidence of colic in US horses. Available at: www.aphis.usda.gov/animal_health/nahms/equine/downloads/equine98/Equine98_is_Colic.pdf. Accessed Aug 13, 2018.
13. Rotily M, Roze S. What is the impact of disease prevalence upon health technology assessment? Best Pract Res Clin Gastroenterol 2013;27:853–865.
14. Squire MM, Riley TV. Clostridium difficile infection in humans and piglets: a ‘One Health’ opportunity. Curr Top Microbiol Immunol 2013;365:299–314.
15. Diab SS, Kinde H, Moore J, et al. Pathology of Clostridium perfringens type C enterotoxemia in horses. Vet Pathol 2012;49:255–263.
16. Macias-Rioseco M, Beingesser J, Uzal FA. Freezing or adding trypsin inhibitor to equine intestinal contents extends the lifespan of Clostridium perfringens beta toxin for diagnostic purposes. Anaerobe 2012;18:357–360.
17. Diab SS. Rodriguez -Bertos A, Uzal FA. Pathology and diagnostic criteria of Clostridium difficile enteric infection in horses. Vet Pathol 2013;50:1028–1036.