The Pathology of Arylmercurial Poisoning in Swine

To produce arylmercurial poisoning, phenylmercuric chloride (PMC) was administered daily to 30 healthy five week-old piglets for periods of up to 90 days. The dosage used ranged from 0.19 to 4.56 mg of mercury (Hg)/kg. Levels exceeding 2.28 mg Hg/kg daily were moderately toxic.

The disease occurring in this intoxication resulted from injury to the kidneys and large intestine. Fetid diarrhea and failure to gain weight were consistent clinical signs. The primary gross lesions were necrotic typhlitis and colitis, and nephrosis. Degeneration and necrosis were found in affected organs. Regeneration was prominent in the proximal convoluted tubules.

The pathology of this disease was similar to that described for mercuric chloride poisoning in other species and, presumably, reflected the ease with which PMC was metabolized to release mercuric ion.

Tissue analysis for mercury suggested that only certain target organs, such as kidney and colon, accumulated significantly high levels of mercury. This, presumably, resulted from rapid metabolism of the compound and excretion of mercuric ion in the kidney and colon. The net effect was to spare other tissues, and to injure the excretory organs when the dose level was sufficiently high.