Acute diarrhea in horses of the Potomac River area: examination for clostridial toxins.

Fecal specimens from horses in Montgomery County, Md, and in Fairfax and Loudoun counties, Va, were examined for Clostridium perfringens type A enterotoxin and for C difficile cytotoxin (92 and 108 specimens, respectively). The toxins were found in feces from horses that had experienced an acute diarrhea syndrome and from clinically normal horses. The toxins did not appear to be primary determinants of the diarrhea syndrome, although they may have contributed to the spectrum of clinical entities observed.