Spain has confirmed a case of bovine spongiform encephalopathy , commonly known as mad cow disease, in the northwestern province of Castilla y Leon, the World Organisation for Animal Health said on Friday. Routine testing showed a positive result for atypical BSE type L disease in a tissue from an animal in a cattle farm in Horcajo Medianero, near the town of Salamanca, the Paris-based OIE said, citing a report from Spain’s agriculture ministry.