Tapeworms (Anoplocephala perfoliata) have become an increasingly common parasite of horses in Australia and many overseas countries. Tapeworms have been known to cause serious bowel disorders and even death. In recent years the relationship between tapeworm infections and spasmodic and ileal impaction colics has been the subject of research investigations in both the USA and UK with interesting results. This is also the case based on the clinical cases seen at the Equine Centre in Werribee.
A recent UK research study by Proudman et al. (1998) found a strong association between ileal impaction colic and tapeworm infection. Within this study 81% of ileal impaction colic cases and 22% of spasmodic colic cases were found to be tapeworm related.
How do horses get tapeworms?
Tapeworms are fluke shaped, and grow between 3-8cm in length. They live at the junction of the small and large bowel in the horse.
Horses can become infected with tapeworms through eating oribatid mites which are found in pasture, hay and straw.
The tapeworm cycle begins with mites eating tapeworm eggs from the horse’s faeces. Approximately 6 weeks after the horse eats the mites the tapeworms being fully mature shed segments containing eggs which are then passed in manure. These segments then break up and release tapeworm eggs which the mites devour, and the cycle continues.
How do you treat tapeworms?
To assist in controlling tapeworms a worming product which includes either pyrantel or praziquantel, (e.g. Equimax), should be included in your parasitic control program at least twice a year in May and September. Not all worming products are effective against tapeworm, for example Ivermectin.
This is supported by a recent USA research study by Little et al. (2002) which found that periodic administration of pyrantel salts (anthelmintic agents which are destructive to tapeworms) appears to be the most effective treatment in the elimination of tapeworms, therefore assisting in reducing the risk of spasmodic and ileal impaction colics.
For advice on setting up a parasitic control program contact your local veterinarian, or check out the Colic Fact Sheet.
Little, D. and Blikslager, A.T. (2002) Factors associated with development of ileal impaction in horses with surgical colic: 78 cases (1986-2000). Equine Vet Journal. 34 (5) 464-468.
Proudman, C.J., French, N.P and Trees, A.J. (1998) Tapeworm infection is a significant risk factor for spasmodic colic and ileal impaction colic in the horse. Equine Vet Journal. 30 (3), 194-199.