September 26, 2022 Sales WVF

Tape Worm In Horses & How To Treat It

Tapeworm & Importance of targeting it

Tapeworms in horses can be tricky to detect. They don’t show up in normal faecal egg counts, and horses rarely show symptoms unless they have a heavy burden. So what can we do about them? Here’s what we know-

Tapeworm infections in horses used to have much uncertainty about the relation of infection and clinical disease. It was once considered harmless, however, due to recent studies, it has shown that it a heavy burden can increase the risk for spasmodic colic and blockages in the small intestine. Heavy burdens can also cause anemia, however, medium burdens can cause no symptoms at all.

Previously, the finding of tapeworm infection was considered incidental, as it only became apparent in horses post mortem. These days, we have a few different ways of detecting a burden, including the use of a saliva sample kit which can be done by owners, and then sent away for testing.

The most common tapeworm species in horses is A.Perfoliata. In appearance, it’s segmented, triangular body is yellow in colour. A fully grown tapeworm can be up to eight centimetres long. Its mouth parts consist of four ‘suckers’ with which it uses to attach itself to the mucosa of the gut wall. Whist attached, it will absorb nutrients from its host.

Tapeworms lay their eggs in ‘capsules’ which are actually the detached segment of its tail. The reason they don’t often show up on faecal egg counts is because the egg capsules don’t float well in the testing medium used, so they are often missed on examination.

Tapeworms require and intermediate host to complete their lifecycle. When the eggs are released into the environment, they are then picked up and ingested by small mites called oribatid mites. These mites live in vast numbers on pasture and can also be found living in hay or straw. Once it has been ingested by a mite, it then takes 12-15 weeks for the egg to hatch into a larvae. The grazing horse will then ingest the mites containing the larvae, and thus potentially leading to tapeworm infection. Once the larvae has developed into an adult tapeworm via various moults, it can start producing eggs within 6-10 weeks.

Until recently, few studies have been done on the damage caused by tapeworms. It is now understood that tapeworm can cause severe damage to the intestinal tract, leading to decreased intestinal motility and colic.

Targeting tapeworm should be done at least twice yearly. Usually it’s recommended that treatment or testing is done in the autumn and again in the spring. (6 months apart) When treating for tapeworm, responsible worming is key. It is extremely important to rotate the active ingredients that you are using, and ensure that you are giving your horse the correct dose for their bodyweight. Under-dosing or using the same wormer each season can cause anthelmintic resistance, meaning that the wormer used will no longer be effective. To discuss your horse’s tapeworm treatment options, feel free to come and see us and speak to one of our Animal Medicines Advisors.

Tapewormers include