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Friday, 11 February 2011

Tapeworm in horses

TAPEWORM (Anoplocephala perfoliata, Anoplocephala magna & Anoplocephaloides mamillana)

The issue of tapeworm burden is certainly one we must consider at all stages of a horses life with perhaps the exception of the early months as foals are rarely infected in the first few months.
It is recommended and has become the norm to treat every six months as this is linked to the life cycle of the tapeworm parasite and traditionally this has been done spring and autumn but in reality it does not have to be at those times.
Tapeworms are an important and potentially very damaging parasite affecting the horse. They preferentially attach themselves to the junction of the small and large intestine the ileocaecal junction. Here, they can cause bowel irritation, intussusception (where one part of the intestine telescopes into another), rupture, or twisting of the intestine.
It is thought that tapeworm may be responsible for up to 20% of surgical colics. Tapeworms are present, to a greater or lesser extent, in the majority of horses.
Parts of the country with acidic soils (for example, heath land), which favour the survival of the intermediate host of the tapeworm (the forage or oribatid mite), tend to have the highest level of infection.
Recent studies have shown that far from being a seasonal problem, tapeworm infection occurs all year round. This is because the forage mite not only lives on pasture, but also survives perfectly well in hay and on bedding, For this reason, six- monthly dosing (at double the standard dose if Pyrantel based products are used) is an essential part of any worming programme when a tapeworm burden is suspected. Worm egg counts cannot determine the level of tapeworm burden for that a blood test is required

AppearanceTapeworms in horses are generally much shorter than dog or cat worms, they are flat, triangular and relatively short being approximately 8 cm long by about 1.5 cm wide. However the equine tapeworm grow up to 20cm long, white in colour. Rarer species can be up to 80cm long. They live in huge numbers attached to the gut wall at a natural narrowing of the gut (the ileocaecal junction).

Can cause colic, sometimes fatal, by blocking blood vessels. Current research estimates that over 20% of cases of spasmodic colic are related to tapeworm burden

There is one predominant type of tapeworm in the UK Anoplocephala perfoliata which is controlled by Pyrantel (Strongid P or Pyratape P at twice the standard dose) the other 2 strains are not common but only controlled by a higher dose of praziquantel (as in Equimax and Equest Pramox but NOT Equitape).
SH Wetherald E-SQP