CLOSTRIDIA AND EQUINE GRASS SICKNESS

Equine grass sickness, a paralysis of the gut resulting from destructi on of the enteric nervous system, occurs mainly in northern Europe, es pecially the east of Scotland and England. A similar, possibly identic al disease, mal seco, occurs in Argentina. The aetiological agent is u nknown but the symptoms suggest the involvement of a toxin and a nutri tional trigger. We hypothesize that C. botulinum type C may be the cau se of equine grass sickness based on the modes of action of its toxins . In an ongoing study we are using serology, toxin detection and attem pts to isolate the organism. C1 toxin has been identified directly in ileal specimens from seven out of 14 clinical cases, and in faeces (re ctal specimens) in seven of 19 cases but also in two of 12 controls. A ntibodies to C1 antitoxin and to cell-surface antigens are found in al l horses but with no clear relationships between disease and antibody level.