The Toxicity of T-2 Toxin in Swine following Topical Application. I. Clinical Signs, Pathology, and Residue Concentrations. PANG, V. F., SWANSON, S. P., BEASLEY, V. R., BUCK, W. B., AND HASCHEK, W. M. (1987). Fundam. Appl. Toxicol. 9, 41-49. T-2 toxin at 0 or 15 mg/kg in 0.75 ml dimethyl sulfoxide was topically applied to 11- to 12-week-old specific-pathogen-free derived crossbred female pigs. Animals were killed on Days 1, 3, 7, or 14 after treatment. Clinical signs and morphologic changes in the skin and internal organs, as well as the residual concentrations of T-2 toxin and its metabolites in plasma, bile, urine, skin, and subcutaneous tissue, were examined. The T-2-treated pigs had signs of lethargy, anorexia, posterior weakness or paresis, and persistent fever. The skin at the site of application was red and swollen initially and progressively became dark red and then purple. By Day 7, at the margin of the exposed area, clefts had formed and were covered by serosanguinous exudate. By Day 14, the affected skin was focally separated from the underlying tissue and covered by a thick scab. The initial skin lesions were characterized as a spongiotic dermatitis and were located mainly in the dermal papillae and stratum germinativum of the epidermis. These lesions progressed to a locally extensive necrotizing dermatitis between Days 3 and 7 that was still evident at Day 14. Healing began on Day 7 and was more prominent on Day 14. Morphologic changes in the internal organs were minimal. They consisted of necrosis of single cells in the follicles of lymphoid tissues and in the exocrine pancreas. Significant amounts of T-2 toxin and several of its metabolites were detected in the skin and subcutaneous tissue of the dosed area for up to 14 days, but neither the parent compound nor its metabolites. as unconjugated free compounds, were found in the plasma, bile, or urine. We propose that the skin and subcutaneous tissue of swine may act as a depot and site of metabolism for T-2 toxin from which the toxin and its metabolites are slowly absorbed.
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