Enterotoxemia in a 2-day-old lamb produced by a type D lambda toxin-positive strain.

type D is a gram-positive bacterium that causes enterotoxemia in sheep, goats, and, less frequently, other animals. This microorganism encodes 2 major toxins, alpha (CPA) and epsilon (ETX). Enterotoxemia occurs when epsilon prototoxin (pETX) is produced in the intestine and is activated by one or more proteases before being absorbed into the general circulation. Traditionally, it was believed that neonatal animals were not susceptible to type D enterotoxemia due to the trypsin-inhibitory action of colostrum in the intestinal tract and the lack of protease activation of pETX, although cases of enterotoxemia have been reported in 2 neonatal goat kids. A 2-d-old lamb, with a history of frailty, hunched posture, shallow breathing, and diarrhea followed by death, was submitted for postmortem examination and diagnostic workup. Autopsy revealed hydropericardium, pulmonary edema, and congested intestines. Histologically, there was pulmonary congestion and edema, and intestinal congestion. type D carrying the gene for lambda toxin was isolated from the small intestine and colon. Both CPA and ETX were detected in the small intestine and colon contents. We speculate that lambda toxin (a protease) activated pETX, and that ETX, in turn, produced enterotoxemia in this lamb.