Aggressive research efforts by Belgian veterinarians have culminated in the identification of numerous indicators or factors–including horse management and pasture characteristics–associated with atypical myopathy, a rapidly developing and fatal disease that destroys skeletal muscles.

"Atypical myopathy is sporadically seen in grazing horses in the United Kingdom and other European countries such as Austria, Belgium, France, Germany, and Switzerland, among others," reported Dominique Votion, DVM, PhD, from the Equine European Centre of Mont-le-Soie and Department of Clinical Sciences at the University of Liège in Belgium.

Typical signs of atypical myopathy include sudden onset of muscle weakness, stiffness, horses that are recumbent and unable to rise, and the production of dark colored urine.

Since atypical myopathy is typically fatal and no treatment or specific disease prevention strategies are currently available, the goal of this study was to identify risk factors for atypical myopathy to potentially identify ways to limit the development of the disease.

In this retrospective study, 57 clinical cases of atypical myopathy diagnosed between November 2000 and May 2005 were included. In addition, information from horses free of atypical myopathy that did (77) or did not (386) graze on the same pasture as the affected horses was also collected.

"Our results indicate that both horse and environmental factors are associated with the development of atypical myopathy," said Votion.

In particular, young, inactive horses in poor or normal body condition (but not overweight horses) might hav