Epidemiology is the study of disease incidence. When we think of epidemiology, we most often think of infectious diseases or tracking down the cause of an epidemic. The same science that has been used to study human diseases has been applied to numerous animal diseases, and recently to the study of equine colic. Because there are so many causes for colic, epidemiology can be helpful in determining those things that are associated with an increased risk of colic. In some cases, it also can help identify the cause.

Mild episodes of colic often are described as gas colic, spasmodic colic, or ileus, depending on the consistency of feces and the character of bowel sounds heard on auscultation. Most of these mild cases of colic have no known cause, and frequently the veterinarian cannot determine which part of the intestine caused the pain. Other types of colic-such as colon impactions or intestinal obstruction due to displacement or strangulation-can be diagnosed by a rectal examination or surgery, but the actual cause or causes of these intestinal disorders often are not known.

Causes Of Colic

Infection with intestinal parasites is known to cause colic. Infection with Strongylus vulgaris once was reported as causing 90% of all colic in horses.10 Although this report never was substantiated by scientific studies, several reports have shown that Strongylus vulgaris larvae disturb intestinal movement, initiate inflammation, and stimulate blood clots in the arteries (thromboembolism) to the intestine.

With the availability of new medications to control intestinal parasites, colic due to Strongylus vulgar