FROM YOUR HORSE - FEBRUARY 2015
BEWARE atypical myopathy
Horse owners are being warned to be vigilant as this devastating disease hits more of the
country's equine population. With a 70% mortality rate, don't let your horse become
a part of this awful statistic by following our vet's advice for prevention
Is the managing equine vet at Pool House Equine Clinic and is a regular Your Horse expert Visit www.poolhousevets.com
Atypical myopathy is a life-threatening muscle disease which results in the destruction of your horse's respiratory, cardiac and skeletal muscles, and it sadly proves fatal in around 70% of cases.
Caused by a toxin called hypoglycin A, which in the UK is found in the seeds of the sycamore tree, it's been on the rise this autumn, with figures recorded by Belgium's University of Liege showing 77 cases in the UK and a total of 173 across Europe* [*FIGURES RECORDED UP TO 17 NOVEMBER 2014. FOR MORE INFORMATION, VISIT HTTP://BIT.LY/1THELYX]. It's thought the warm summer led to high numbers of seeds, which were then widely spread by windy weather.
Times of high risk include the autumn when the seeds drop to the ground and can be easily accessed by grazing horses, and also the spring.
Horses most vulnerable to this awful disease are those kept on fairly bare pasture surrounded by trees, including sycamores, and who aren't given supplementary forage or feed, making the ingestion of seeds and leaves more likely.
If a horse does eat sycamore seeds, it's pot luck as to whether he develops the disease, as equine vet Gil Riley explains. "The concentration of hypoglycin A varies between sycamore seeds, and even between seeds from the same tree. Some horses who eat a large volume of seeds might get lucky by eating those with low levels of toxins, whereas another may only eat a few that contain sufficient toxins to cause a serious problem."
Look out for symptoms
Atypical myopathy is often misdiagnosed as colic as the first stages can appear very similar.
"Common symptoms include trembling muscles and stiffness. Horses with the disease are in considerable pain and will often appear weak, dull or lethargic, possibly even lying flat out," says Gil.
If your vet suspects the disease, he or she will examine your horse carefully and check his vital signs including pulse and respiration rates. As the disease affects the respiratory muscles, his breathing may be quicker and laboured, while his pulse may be elevated if the cardiac muscle has also suffered. Damaged heart muscles can cause your horse to go into cardiac failure, and in some cases the muscle damage can even lead to the blood becoming acidic.
"Your vet will also want to check the colour of your horse's urine," says Gil. "The darker it is the worse the prognosis as this indicates a lot of muscle breakdown. His mucous membranes (such as his gums) will also be examined - in atypical myopathy patients these are often overly reddened."
Act fast to treat him
Sudden death is a frightening possibility in cases of atypical myopathy, and if it's not caught early enough, some horses may be beyond treatment so the kindest thing is to put them to sleep. There's no antidote for hypoglycin A, so treatment involves fighting the clinical effects it has by administering fluids to clear the system and prevent dehydration, which also supports kidney function and protects the other organs from toxicity. Electrolytes are also useful for rehydration, while vitamin A and selenium are important to support damaged muscles.
Smaller horses or ponies with atypical myopathy seem to have a poorer prognosis than larger or heavier animals. It's thought this is because bigger animals suffer less muscle damage relative to the amount of muscle they have.
"It's the luck of the draw as to which type of muscle is affected - skeletal, cardiac or respiratory - and it's preferable for it to be the skeletal muscles - they're easier to flush out and are better able to recover," says Gil.
Nursing or palliative care is important for recovery from atypical myopathy, as is early diagnosis. The mortality rate of around 70% can be lowered to 50% with the right treatment, but it's key to catch cases early.
The simplest way guard against atypical myopathy is to keep your horse away from sycamore seeds, so learn to identify sycamore trees and fence off any in or around your fields. You also have to be vigilant over any surrounding grazing as the shape of the seeds means they can fly a distance from the tree. If you have sycamores near your grazing, regularly inspect it carefully and pick up any seeds.
Supplying your horse with extra forage such as hay or haylage should curb his hunger and deter him from munching on any seeds that remain in his field. Having fewer horses in each field also reduces pressure on the grazing, and reducing the amount of time your horse is out for can also be a safeguard.
If you have any concerns about your horse and suspect atypical myopathy, speak to your vet soon rather than later.
NOW IF I HAD ANY SYCAMORE TREES NEARBY I'D CUT THEM DOWN, I'D JUST GET RID OF THEM PERIOD…..THE VERY BEST WAY TO MAKE SURE YOUR HORSE/S DOES NOT GET THIS DISEASE - Keith Hunt
"It happened to me"
Your Horse reader and horse owner Shirley Wakadia lost her beloved Dartmoor Hill Pony, Ishtar, to this awful condition in November. Here she shares her advice with fellow horse owners as she hopes to prevent more horses succumbing to this devastating disease.
"I was poo picking in the field as normal at about 7am when I saw Ishtar lying down," says Shirley. "1 thought he was just having a lie-in but as I got close, I could see his eyes were glazed over. My immediate thought was that he was dead, but he managed to get up and walk over to the fence -I could see it was really hard for him. When the vet arrived he took blood and urine samples and the disease was confirmed. Due to the irreversible damage to his kidneys, Ishtar was put to sleep. 'This disease is becoming so prevalent at the moment, my advice for other horse owners out there is look for these helicopter seeds - scour your whole field and not just around the area of the offending tree. They're so commonplace that you don't realize they're there, but when you know what you're looking for they become easier to spot. If possible, move your horse to another field and remove the risk entirely - it's just not worth it. I felt like my world had ended when it happened as there was so much I wanted to do with Ishtar. It's the sort of thing that you think will never happen to you but I've learned the hard way that it does. I hope in some way I can help make sure this awful experience doesn't happen to anybody else."
THE SYCAMORE TREE GROWS IN PARTS OF NORTH AMERICA…..MAKE SURE YOUR HORSES ARE NOT CLOSE TO THIS TREE - Keith Hunt