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Autumn and winter worming
During the autumn and early winter the focus of any responsible and
sustainable worming programme should be on the management of tapeworm
and encysted small redworm – neither of which show up in a standard FWEC.
Ben Gaskell, Pfizer’s veterinary advisor explains how these parasites
can be tackled to best effect.
The truth about tapeworm
Tapeworms are very common in UK horses1,2,
but their definitive life cycle is still not completely understood. What
we do know is that tapeworm infection can be linked to potentially
serious colic3. We
also know that a faecal worm egg count won’t definitively identify a
tapeworm burden and that not all wormers are effective against this
parasite.
Although tapeworm infection shows no strong seasonality,
exposure is greater during periods of prolonged grazing.
Consequently, treatment should be undertaken in the autumn following
summer turnout on pasture4,
with repeat treatments usually recommended every six months5.
The treatment for tapeworm in horses involves either a double-dose of a
pyrantel-based wormer or a wormer containing praziquantel. The latter is
regarded as offering an effective single dose treatment for the control
of equine tapeworms.
The time-bomb effect of encysted small redworm
Encysted small redworm larvae may account for up to 90% of the redworm
burden in your horse 6.
Even if the horse has shown a negative or low count it could still be
harbouring several million of these dormant parasites, hidden within the
gut wall7.
Encysted small redworm can remain dormant inside a horse for up to two
years, but they usually ‘wake-up’ in the late winter or early spring,
developing and emerging from the gut wall all at the same time. In
severe infestations this can lead to a disease syndrome known as ‘larval
cyathostominosis’, causing diarrhoea and colic with up to a 50%
mortality rate7. Treating encysted small redworm successfully
in the late autumn or early winter is important in order to minimise
this serious risk.
Moxidectin is recognised as the only single dose treatment for encysted
small redworm. It has been shown to kill the larvae in-situ, without
resulting in severe inflammation of the gut wall that other multi-dose
treatments may cause8. In addition, Moxidectin is licensed
for persistent activity against small redworms, killing larvae ingested
as the horse grazes for up to two weeks after treatment.
1.
Lyon S et al, Veterinary Record (1995) 147, 456-457
2.
Owen RH et al, Veterinary Record (1998) 123, 562-563
3.
Proudman CJ Journal of Equine Veterinary Science (2003) 23 (1)
6-9
4.
Proudman CJ et al Equine Veterinary Journal (1998) 30 (3) 194-199
5.
Proudman and Matthews, In Practice (2000) 22, 90-97
6.
Bairden K. et
al
(2001) Veterinary Record 148, 138-141
7.
Dowdall S.M.J. et
al
(2002) Veterinary Parasitology 106, 225‑242
8. Steinbach T. et
al
(2006) Veterinary Parasitology 139, 115‑131
EQUEST and EQUEST
PRAMOX are registered trademarks of Pfizer Ltd. EQUITAPE is a registered
trademark of Bayer Ltd. EQUEST contains moxidectin and EQUEST PRAMOX
contains moxidectin and praziquantel. EQUITAPE contains praziquantel.
Advice on the use of these or alternative treatments must be sought from
the medicine prescriber POM-VPS. Further information from
Pfizer
Animal Health, Pfizer Ltd, Walton Oaks, Dorking Road,
Walton-on-the-Hill, Tadworth, Surrey KT20 7NS
Use medicines responsibly: www.noah.co.uk/responsible
