Samples Sought For Donkey Besnoitiosis Research

Researchers at the Cornell University College of Veterinary Medicine are seeking help from owners to better understand an emerging donkey disease: besnoitiosis.

According to SallyAnne L. Ness, DVM, a large animal internal medicine resident at Cornell, researchers are seeking potentially affected donkeys to study as well as herds of donkeys to test for the presence of the virus.

"In the fall of 2010, two Pennsylvania donkeys were donated to the Cornell University Hospital for Animals after samples sent to the Pennsylvania Animal Diagnostic Laboratory revealed infection with Besnoitia bennetti—a rare protozoan parasite closely related to Sarcocystis, Toxoplasma, and Neospora," Ness explained in an informational article she penned. "In the wake of those two cases, researchers at Cornell University have diagnosed multiple infected donkeys across several Northeastern states, plus Tennessee, Texas, Minnesota, Michigan, Oregon, and Washington. As the number of identified cases continues to grow, it appears that besnoitiosis may be emerging as an important infectious disease of donkeys in the United States."

Affected donkeys develop tiny cysts (about 1 mm in diameter) in various external locations including the face, legs, ears, and perineum, and internally in the nasopharynx. Currently, there are no treatment options available.

"There are currently studies under way at Cornell University investigating epidemiological risk factors for the development and transmission of besnoitiosis within donkey populations," Ness said. "Additionally, the utility of serology as a diagnostic screening test for identifying infected donkeys is being evaluated.

"Further investigations are needed to gain a better understanding of disease transmission, treatment, and ultimately prevention," she added. "Although besnoitiosis has not yet been reported in horses in North America, cases have been described in Africa, and the potential for similar infections in the United States cannot be excluded as a possibility."

Donkey owners who would like to have their herd examined for the presence of besnoitiosis or who believe a donkey is infected by the protozoa are asked to contact Ness at or 607/253-3100. Histologic and serologic samples can be shipped; however, arrangements must be made prior to shipping. 

About the Author

Erica Larson, News Editor

Erica Larson, news editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in eventing with her OTTB, Dorado.

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