Rapid and Reliable Test for Diarrhea-Causing Toxin Identified

Toxins produced by the bacterium Clostridium difficile can cause diarrhea in adult horses and foals. The high economic impact associated with treatment costs, considerable animal losses to disease associated with mortality and debilitation, and the potential for spread of infection to other susceptible animals and even humans make this an important disease threat to the horse industry.

A rapid diagnosis is important to quickly institute appropriate therapy to increase recovery rates and minimize spread of disease.

"At present, the best way to diagnose C. difficile is the cytotoxicity assay (CTA), which is neither readily available nor particularly easy to quickly perform," explained study co-author Carlos Medina-Torres, DVM, MSc, a DVSc candidate at the Ontario Veterinary College at the University of Guelph. Torres presented on the topic at the American College of Veterinary Internal Medicine (ACVIM) Forum, held June 4-7 in San Antonio, Texas.

In an effort to improve the ability of clinicians to diagnose C. difficile in horses with diarrhea, Medina-Torres and colleagues obtained 72 fecal samples from hospitalized horses with acute diarrhea and compared the CTA results to the results of the C. DIFFICILE TOX A/B IITM ELISA (TECHLAB®, Inc; Blacksburg, Va), an enzyme-based test capable of detecting toxins produced by the bacterium C. difficile.

Of the 72 samples, 19 (26.4%) were positive for C. difficile toxins by the CTA test. Of these, 16 were also positive by the ELISA test indicating that both tests were equivalent in their ability to identify C. difficile-positive horses.

According to Medina-Torres, "This high level of agreement between the two tests suggests that this particular ELISA is a reliable test that can therefore be used in the clinic setting to rapidly diagnose C. difficile-associated diarrhea in horses."

A more rapid diagnosis means that appropriate treatment and infection control practices can also be more quickly initiated concluded Medina-Torres in the research abstract, "Validation of a Commercial Enzyme Immunoassay for Detection of the Presence of Clostridium difficile Toxins in Feces of Horses with Acute Diarrhea."

About the Author

Stacey Oke, DVM, MSc

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she's worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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