Emetic action of staphylococcal enterotoxin A on weanling pigs

Peroral and intraduodenal administration of staphylococcal enterotoxin A (SEA) to weanling pigs elicited an emetic response. Peroral administration of an emetic dose of SEA resulted in a single emetic episode occurring 90 to 180 min after dosing. Intraduodenal administration via a surgically implanted catheter of 100 or 150 micrograms of SEA resulted in multiple emetic episodes occurring 150 to 210 min after dosing, suggesting an intestinal site of action for SEA. The 50% emetic dose for perorally administered SEA was between 40 and 50 micrograms for 4.1- to 9.1-kg weanling pigs and 20 micrograms in 0.9- to 2.3-kg weanling pigs. Neurobehavioral responses, including alternating periods of drowsiness and restlessness, staggering, temporary loss of the righting reflex, and refusal to feed were also observed in pigs given an oral dose of SEA. Based on the demonstrated responsiveness of pigs to SEA, pigs should be considered suitable animal models for studies on the sites and mode of action of the toxin.