Jenny is an IHDG member and her pony unfortunately died of it a year ago. Since then her mother's pony had a bout of it and hoorah survived. She is very keen for people to know more about it. Unfortunately the vets don't seem to know that much about why it occurs. To save you all becoming a friend, this is what she wrote:
What is it? Put bluntly, a fast killer, 88% of cases are fatal in as little as 12 hours from onset. It occurs in the paddock, affecting the horses muscles in a similar way to Azetoria (tying up), only without the exercise element.
The cause is believed to be a bacteria called CLOSTRIDIUM SORDELLII. I know it is an anaerobe (i.e. does not tolerate oxygen), so presumably in the soil or plants.
The enzymes released by the horses body cause rapid muscle damage, this is to all muscles which of course includes the heart, lungs etc... Atypical means no typical scenario. The most commonly affected animals are the younger ones out at grass 24/7, i.e. 18 months plus and not in work. Those not immunized, rugged, fed supplementary feed or provided with shelter are also higher on the risk list.
Having pointed out what is known to be the most commonly affected, we have had two cases,The first was a five year old gelding Peppercorn, fit, in regular work, recently started his vaccinations, fed daily (hard feed and hay). The day before he was worked and appeared fine, lots of energy. 11 hours later the following morning I found him unable to move, almost a lamanitic type stance, waves of pain that looked almost (not quite) like colic. Waves of muscle tremors, yet he was still eating the grass at his feet, tummy gurgling, did a dropping. The vet was called immediately. Initially the vet diagnosed a fractured pelvis or shoulder, took bloods, gave advice and left, 2 ½ hours from my first arriving at the field he fell to the ground and passed away. The blood results revealed highly elevated CK and AST levels. This was in the autumn of 2009, following a week of heavy rain and high winds.
Peppercorn, RIP. lost to Atypical Myoglobinuria in 11 hours from onset. 5 years old.
Our second case was in May 2010, sunny summer type weather, we opened up the field believing it was past “that dangerous season”. There was a light shower that night, not windy. Poppy, 18 months old, at a show the day before and placed, full of youthful energy. As before, found her the following morning with the same lamanitic type stance, this time however we simply phoned the vets and told them we were on our way in. They did send a vet to us regardless, who arrived before we had managed to load Poppy and was very helpful in helping us load, poor Poppy could only cope with one or two steps at a time, however we knew the longer we took the harder it would become for her. She was lucky we got her to hospital in time and on a drip, her CK muscle enzymes peaked at 1.7 million and her AST muscle enzymes peaked at over 2 million, and by all accounts she should not have made it, but she did.
Poppy, 12 hours before we found her with Atypical Myoglobinuria
Poppy in hospital, after the drip had been removed, this is only a few days after she was placed at a show - muscle loss etc.. as a result, but she survived, one of the lucky 12% that make it.
Poppy in the show ring, fully recovered.
Poppy, the sparkle back in her eyes!
At the same time a friend of ours some 20 miles away also had a case, her pony however seemed off colour for a few days prior, which she just put down to having had her flue injection. I have subsequently looked further into this and it would appear that Atypical Myopathy can present itself in either form, i.e. A bit off colour a couple of days prior or instant being our own personal experience. We had many discussions with our vet, who informed us the oldest case they have had is a 15 year old, some arrive unable to stand and are literally dragged out of the horse box. They have also had cases with horses that are rugged, and even a fit hunting horse that was part stabled, hence this is Atypical.
RISK SEASONS, WEATHER CONDITIONS: Autumn & Spring are peak seasons. Rain/showers and wind.
AREAS OF RISK: In particular paddocks with a slope and natural shelter at the base. Areas where the autumn leaves collect. This has happened in flat paddocks as well as sloped ones, the common factor being natural shelter under trees. I can only presume these sheltered areas allow the bacteria to collect/occur in large quantities. I do not know if it is in the soil, grass or other vegetation.
SUMMARY OF WARNING SIGNS:
1. Lethargy, reluctance or inability to move.
2. Head held low, an almost lamanitic type stance (if still standing)
3. Will still eat and poo.
4. Quarter muscles tense, possibly with some trembling, shoulders the same. Muscles very hard, noticeable along the top of the neck, feels like a guitar string.
5. The trembling seems to come in waves.
6. Red nostrils
Another sign is dark urine, however that means internal damage has started.
www.myopathieatypique.be/
I'm going to have to go and fence off the top and bottom of my field, it's on a downhill slope with trees at the top and bottom and all the leaves have dropped. Might have to move onto his winter field early as that only has leaves all over the bottom