Neurotoxic syndrome produced in chickens by a cyclic phosphate metabolite of tri-o-cresyl phosphate--a clinical and pathological study.

A clinical and neuropathological comparison was made between chickens poisoned with tri-o-cresyl phosphate and those treated with the major cyclic phosphate metabolite of tri-o-cresyl phosphate. Ataxia was evident with both materials, and the degree of peripheral neuropathy increased with higher doses of these agents. Morphological changes were evident with the onset of symptoms and increased in number as the neurological signs progressed. Demyelination of the spinal cord following administration of the metabolite occurred at doses considerably below those necessary to effect peripheral nerve degeneration. Axon and myelin damage was prominent with both agents. The relationship between these effects and those produced by certain other organophosphates such as dyflos (diisopropyl fluorophosphonate) is discussed.