Professor Didier Serteyn and Dr Dominique Votion, both from the University of Liège Faculty of Medicine and the Mont-le-Soie European Equine Centre co-ordinate an international research network, aiming at finding out more about atypical myopathy in horses. Although there has been a recent increase in this muscular illness, researchers are keeping pace with it, and early in 2010 two joint publications will be put forward to allow the disease to be better understood.

Ten years ago, nobody had heard of atypical myopathy in horses, although a series of deaths in very similar circumstances had been noticed. In 1984, researchers noticed several sudden deaths in Scotland. They saw that all the horses had abnormally dark urine. "The urine is dark because myoglobin, a muscle constituent, is released after muscular destruction", states Dr Dominique Votion. The condition was therefore named “atypical myoglobinuria”. “‘Atypical’ comes from the particular conditions under which it appears. Myoglobinuria had to this point been associated with exercise mypathies. But in this case, the horses had not carried out physical effort prior to their deaths.” A few years later, Dr Votion’s research led her to the following observation: some animals died even before having the dark urine was produced. The presence of myoglobin in the urine is but a clinical sign, one clue among others which combine to prove the existence of the illness. In reality, the condition attacks muscular tissue. This is myopathy. “The illness thus had to be renamed, says Dr Votion. “I introduced the term ‘atypical myopathy’ in 2004.”

Many known human myopathies are genetic. In horses, they often begin with excessive physical effort. Atypical myopathy is contracted in a specific environment, mainly in the autumn and spring. There is no hereditary element to it. There is also no risk of contagion, although it remains no less insidious. It attacks all the horse’s muscles and does so rampantly. “Ultimately, around 85% of horses contracting this condition die from it, and the average length of survival is 24 hours. This is the big difficulty, both in terms of intervention and for the morale of the owner. The owner sees the animal in perfect health one day and finds it dead the next. Horses with atypical myopathy seem to be starving. The appetite can be mistakenly be considered as synonymous with the chances of survival. In reality, their organism cannot use the energy from the lipids which they wolf down. They are eating, therefore, to overcome an energy deficiency.”

Although it is neither hereditary nor contagious, the exact cause of the disease has not yet been detected. Several plausible explanations are beginning to emerge, however.