Atypical Myopathy has been recognised as a sudden onset of muscle disease for over 60 years but it’s cause was only identified in 2013. Hypoglycin A is a toxin found in the seeds, seedlings and leaves of some types of Sycamore Trees (Acer Pseudoplatanus).
There are more than 25 species of Acer tree and and not all species have the HGA toxin. (Hypoglycin A).
Lots of research has taken place over the last decade by the Royal Vet College, supported by The Horses Trust, and a test is now available that enables samples from sycamore leaves, seeds and seedlings to be tested for the toxin Hypoglycin A.
As not all sycamore trees contain the toxin the new test can help horse owners to assess the risks of their horses’ fields and take precautions if necessary.
There is however still a lot to discover; researchers do not yet know if toxin levels stay the same throughout the year or year by year. It is possible they are affected by variables such as climate or soil conditions.
You can get your sycamore trees tested by sending samples to the RVC.
You can read their fact sheet that tells you how to collect samples.
And find the submission form HERE.
Know the clinical signs
It is important to know that Atypical Myopathy is a serious condition and can often be fatal if not diagnosed and treated very quickly.
General weakness : horses struggle to walk, stand and breathe
Many horses develop heart problems
Horses appear depressed with low hanging heads
Muscle trembling
Signs of colic – yet they often still have an appetite
Brown or dark red urine
Severely affected horses are unable to stand
Prevention
Prevention is better than cure so be vigilant when checking your paddocks and water supplies.
The helicopter style seeds can travel a long way and although horses do not typically choose to eat sycamore seeds, when pastures are bare, there is a greater tendency for them to be ingested as horses are foraging for every last blade of grass.
If your horse has access to a natural water supply then be aware that seedlings at the edge of watercourses can also contaminate water supplies, especially when trampled as horses walk across them.
- Identify trees both around your fields, as well as those in close proximity. If you are unsure you can check here: www.tree-guide.com.
- Collect seeds or exclude horses from affected areas using electric fencing or stabling.
- Feed supplementary hay to try and prevent horses from excessive foraging for short blades of grass and inadvertent ingestion of seeds.
If you think your horse has been exposed to Sycamore seeds, seedlings or leaves, monitor them closely and speak to your vet if you are at all concerned.
Specific blood tests have been developed to both measure exposure to the toxin and to make a diagnosis.
Remember, although Atypical Myopathy is fatal in three quarters of horses, if diagnosed and treated quickly, horses can make a full recovery.
By educating as many horse owners as possible to the risks, and by understanding how we can protect our horses, hopefully we can work together to prevent cases occurring.
