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Using Bacteria to Deworm HorsesBy Kentucky Equine Research Staff · October 6, 2015

In the face of a persistent increase in resistance of equine internal parasites to available chemical dewormers, Martin Nielsen, D.V.M., Ph.D., is choosing a different approach to parasite control. Nielsen, an assistant professor at the University of Kentucky, is literally fighting fire with fire, using bacteria to naturally eradicate parasites in horses.

“In a project that we refer to as, ‘Let the Germs Get the Worms,’ we are using proteins produced by the bacterium Bacillus thuringiensis to kill strongyle larvae,” Nielsen explained.

Strongyles are known to be developing resistance to a number of chemical dewormers, including popular products containing pyrantel and benzimidazoles, including fenbendazole.

In the preliminary phases of their research, Nielsen and colleagues cultured strongyle parasite larvae in the laboratory and exposed them to different doses of the protein Cry5B obtained from B. thuringiensis.

“We found that Cry5B has potent activity, successfully killing strongyle larvae in a laboratory setting using cultured larvae. It even killed parasite populations that are known to be resistant to chemical dewormers,” shared Nielsen.

He added, “The next step is to take our laboratory results and see if the protein can kill strongyle larvae in vivo and determine the safety of this protein in live horses. Further, we plan on testing this protein on ascarids as well. We are hopeful for positive results considering this technology has already proven effective in pigs.”

The researchers are enthusiastic about this deworming option and are actively raising research dollars to fund their work through crowdfunding. Researchers anticipate it will take another five years before the technology is available to horse owners.