Thu 30th Oct 2014Equine Atypical Myopathy cases dramatically rise this autumn Polo Times talks to Nicola Bell BVetMed MRCVS from Riverside Vets Equine about what signs to look for in your ponies
Atypical Myopathy is a highly fatal muscle disease, most commonly seen in young horses out to graze in autumn and spring, in both the UK and Northern Europe. It causes severe damage to muscles, affecting postural and respiratory muscles. Atypical Myopathy is attributed to the toxin Hypoglycin A, which is found in Sycamore seeds. The seeds can contain a variable amount of this toxin, so there is not necessarily a correlation between quantity ingested and severity of disease. Hypoglycin A interferes with muscle metabolism, and the breakdown of muscle tissues causes waste products to be released in high levels into the blood stream, which in turn results in kidney failure. Unfortunately there is no antidote available, so treatment consists of intravenous fluid therapy, pain relief and attentive nursing care – this is often best achieved via admittance to an equine hospital. The prognosis is very poor, and survival rates are reported as low as 26%.1
Nicola Bell reports to Polo Times that, “there have been an abnormally high number of cases reported this autumn.” Ms. Bell advises that the clinical signs to look out for include: weakness, muscle tremors, pain, lethargy, reluctance to walk, recumbancy (lying down with difficultly standing), discoloured urine (brown-red), difficulty breathing or swallowing. These are often confused with signs of colic.
Prevention of the disease requires restricting horses from gaining access to Sycamore seeds; avoid pasture with Sycamore trees, fencing off areas where seeds/leaves have fallen. Reduce stocking densities down to ensure that there is enough grazing, or alternatively supplementing the pasture with extra forage.
If you suspect a horse is suffering from Atypical Myopathy, contact your vet as a matter of urgency. Try not to move the horse as excessive movement may cause further muscle damage. If the horse urinates, try to collect a urine sample as this will aid the vet in their diagnosis. Removal of all other horses grazing on the same pasture and careful monitoring for clinical signs should be undertaken.
Reference: 1. European outbreaks of Atypical Myopathy in grazing equines (2006–2009): Spatiotemporal distribution, history and clinical features, G. van GALEN et al, Equine Veterinary Journal Volume 44, Issue 5, pages 614–620, September 2012
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Photograph: The classic Sycamore 'Helicopter' can be fatal for grazing horses
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