Scientists Study Bloodworm-Associated Colic in Horses

Most bloodworm-associated colic patients did not exhibit severe colic signs, which could make this potentially deadly condition difficult to diagnose, researchers found.

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bloodworm-associated colic
Surgeons performed exploratory laparotomy in 21 horses, 11 of which were euthanized due to their presumed poor prognosis. | Photo: Courtesy Dr. Tina Holberg Pihl

The bloodworm, Strongylus vulgaris, is small enough to fit into horses’ arteries, but it can cause big—even life-threatening—problems for its equid hosts. Researchers have determined that the survival rates for horses with bloodworm-associated nonstrangulating intestinal infarctions (NSII) are poor whether they’re treated medically or surgically.

As bloodworms migrate through the horse’s intestinal arteries, they cause damage that leads to clotting. When the clots detach or large amounts of larvae build up in smaller arteries, blockages can occur. The result is intestinal wall infarction and inflammation, a condition called NSII or thromboembolic colic.

“If left untreated the intestine will rupture and the horse will die from shock,” said Tina Holberg Pihl, DVM, an associate professor at the University of Copenhagen, in Denmark

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Written by:

Katie Navarra has worked as a freelance writer since 2001. A lifelong horse lover, she owns and enjoys competing a dun Quarter Horse mare.

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