The largest outbreak of equine atypical myopathy in Europe has ended with freezing winter temperatures, with a record number of 371 reported cases, according to a group of researchers in Belgium.

Atypical myopathy (AM) causes severe generalized weakness and stiffness, often ending in death. Urine becomes coffee-colored, and blood workups show significant increases in plasma levels of creatine kinase.

France, Germany, and Belgium were most affected, with 124, 92, and 64 cases, respectively, but Ireland, The Netherlands, Denmark, Switzerland, the U.K., and Luxembourg also reported instances of AM in autumn 2009.

"Atypical myopathy is not a reportable disease, and given its high mortality rate, the horses often die even before they are diagnosed. So these numbers are certainly underestimated," said Gaby van Galen, DVM, MSc, Dipl. ECEIM who, along with Dominique Votion, DVM, PhD, collect data via the Atypical Myopathy Alert Group based at the University of Liège. The group consists of veterinarians, owners, and veterinary medical schools throughout Europe who report cases