Atypical Myopathy Cases

Over the last few weeks we have seen several cases of the severe disease, Atypical Myopathy.

Atypical Myopathy (AM) is a highly fatal muscle disease in horses in the UK and Northern Europe. It results in destruction of respiratory, cardiac and postural muscles. Even with intensive veterinary treatment, severely affected horses may die. Several horses from one location can be affected and outbreaks occur most commonly in the autumn. Early veterinary intervention is key in trying to prevent this disease from rapidly progressing.

Clinical signs include:

• reluctance to move • muscular weakness • stiffness • apparent sedation or depression • sweating • fine muscle tremors • dark coloured urine • high respiration rate and difficulties breathing • colic like symptoms • complete collapse • vigorous head shaking/vocalisation

Recent research has suggested that the seeds of the sycamore tree are likely to cause atypical myopathy in Europe. The seeds are commonly referred to as helicopters.

In practical terms, horses’ ingestion of sycamore seeds in the autumn could be reduced by:

  1. Hoovering-up/picking up sycamore seeds
  2. Fencing off areas where sycamore seeds have fallen from trees
  3. Regularly inspecting fields to ensure seeds have not blown in from sycamore trees nearby
  4. Supplying extra forage (hay or haylage) especially where pasture is poor
  5. Reducing stocking density so there is plenty of palatable grazing for every horse
  6. Turning out horses for only short periods rather than extended periods of the day (ideally <6 hrs)