Todayโs path rounds are on ๐ฅ๐๐ซ๐ ๐ ๐ฌ๐ญ๐ซ๐จ๐ง๐ ๐ฒ๐ฅ๐๐ฌ!
๐๐ก๐๐ญ ๐ข๐ฌ ๐ข๐ญ?
๐๐๐ซ๐ ๐ ๐ฌ๐ญ๐ซ๐จ๐ง๐ ๐ฒ๐ฅ๐๐ฌ are a type of ๐ซ๐จ๐ฎ๐ง๐๐ฐ๐จ๐ซ๐ฆ that is considered to be one of the most significant parasites affecting horses. These roundworms are typically found in the cecum and colon of the horse.
๐๐ก๐จ ๐ ๐๐ญ๐ฌ ๐ข๐ญ?
Horses get this condition! Any age, breed, or lifestyle of horse can be affected.
๐๐ก๐๐ญ ๐๐๐ฎ๐ฌ๐๐ฌ ๐ข๐ญ?
Large strongyles are more scientifically known as ๐๐ญ๐ซ๐จ๐ง๐ ๐ฒ๐ฅ๐ฎ๐ฌ ๐ฏ๐ฎ๐ฅ๐ ๐๐ซ๐ข๐ฌ. Typically, horses ingest the larvae of this parasite while grazing on pasture. From there, the larvae penetrate the intestinal mucosa and enter small arteries. Their main destination is the ๐๐ซ๐๐ง๐ข๐๐ฅ ๐ฆ๐๐ฌ๐๐ง๐ญ๐๐ซ๐ข๐ ๐๐ซ๐ญ๐๐ซ๐ฒ, one of the large vessels that supplies blood to the intestinal tract. Once they reach this artery, they grow and develop over the course of 3-4 months into immature adults. These immature adults swim down the artery back to the cecum or colon of the horse, where they will produce eggs to carry on their life cycle.
๐๐ก๐ฒ ๐ข๐ฌ ๐ญ๐ก๐ข๐ฌ ๐ ๐ฉ๐ซ๐จ๐๐ฅ๐๐ฆ?
The adult worms typically donโt cause too many issues, so itโs the larval stages living in the arteries that are the main concern. These larval stages can irritate the artery, and disrupt the normal smooth inner surface of the vessel. This predisposes the artery to ๐ญ๐ก๐ซ๐จ๐ฆ๐๐จ๐ฌ๐ข๐ฌ, because the coagulation factors in the blood will have a roughened surface to attach to! When this happens, a big blood clot can form that blocks blood flow to the intestine. This can lead to ๐ข๐ง๐๐๐ซ๐๐ญ๐ข๐จ๐ง (death of tissue) of the intestine, and severe ๐๐จ๐ฅ๐ข๐ (intestinal pain).
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐๐ข๐๐ ๐ง๐จ๐ฌ๐๐?
The parasite can generally be identified on a ๐๐๐๐๐ฅ ๐๐ ๐ ๐๐จ๐ฎ๐ง๐ญ, assuming that there are adults producing eggs at the time of fecal collection. However, it is not the adults that cause problems, so it is possible for a horse to be affected by the larval migration without showing any eggs in their feces. In these cases, ๐๐ฑ๐ฉ๐ฅ๐จ๐ซ๐๐ญ๐จ๐ซ๐ฒ ๐ฅ๐๐ฉ๐๐ซ๐จ๐ญ๐จ๐ฆ๐ฒ (surgical exploration of the abdomen) is the best method of diagnosis, to identify infarcted intestine.
๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ญ๐ซ๐๐๐ญ๐๐? ๐๐จ๐ฐ ๐ข๐ฌ ๐ข๐ญ ๐ฉ๐ซ๐๐ฏ๐๐ง๐ญ๐๐?
If the horse has infarcted intestine, then surgical removal of the affected tissue is the best means of treatment. Otherwise, treatment and prevention involves using anti-parasitic medications like ๐ข๐ฏ๐๐ซ๐ฆ๐๐๐ญ๐ข๐ง or ๐ฆ๐จ๐ฑ๐ข๐๐๐๐ญ๐ข๐ง to kill off the larvae and adults. Good pasture and manure management can also help prevent this worm from spreading!
๐๐ก๐จ๐ญ๐จ๐ฌ
1-3) Worms chillinโ in the colon and cecum of horses.
4-5) Irritated, roughened cranial mesenteric arteries after larval migration.
6) Some very sad, hemorrhagic and black intestine after cranial mesenteric thrombosis.
๐๐จ๐ฎ๐ซ๐๐๐ฌ
Maxie, G. Jubb, Kennedy and Palmerโs Pathology of Domestic Animals, Volume 2. Sixth Edition.
Photos 1-6 ยฉ Noahโs Arkive contributors Tyler, Boosinger/Chang, Crowell, Acland licensed under CC BY-SA 4.0.
