Studies have recently concluded that there is a link between equine tapeworms (Anoplocephala perfoliata) and horse colic. Tapeworms were thought to be non-pathogenic, but researchers at Università degli Studi di Perugia found evidence to "support a correlation between colic and A. perfoliata infestation in the horse."
Tapeworm infestations can cause spasmodic colics but more serious tapeworm threats include ileal impactions and intussusception.
Tapeworms congregate at the ileocecal junction, where the small intestine, the colon and the cecum form a pouch that is the beginning of the large intestine. Irritation can cause a thickening of the bowel wall and abnormal gut motility. Digested food cannot pass and an impaction colic results. Up to 80% of illeal impactions are tapeworm-related.(1)
Lesions, thickening and damage to the intestinal wall and abnormal gut motility can also cause intussusception, a serious condition in which a section of the gut telescopes into an adjacent section. intussusception is a medical emergency. Ileocecal Intussusception Colic is believed to be exclusively caused by tapeworms.(1)
Tapeworms are difficult to diagnose and show no strong seasonality, but exposure is greatest during periods of prolonged grazing.
Tapeworm infection levels vary across the US. Speak to your veterinarian about developing a program to manage this parasite.
(1) Proudman CJ et al, Equine Veterinary Journal (1998) 30 (3) 194-199.