Sulphide-induced polioencephalomalacia in lambs.

Polioencephalomalacia (PEM) was induced in four of 10 lambs by the administration of a sulphide solution into the oesophagus at 20 min intervals for a period of 40 to 120 min. Signs of neurological dysfunction occurred in all 10 lambs during that time and included stupor, visual impairment and seizures. Gross autofluorescent and microscopic lesions in cerebrocortical grey matter were present as soon as 20 h after sulphide administration and were indistinguishable from lesions in naturally occurring disease. These findings, when considered together with an earlier study that revealed an association between high ruminal concentrations of sulphide and PEM, indicate that this disease can result from sulphide toxicosis, independent of the metabolic status of thiamine.