Polio Syndrome in Ruminants
Guy Sheppard, DVM
Polioencephalomalacia “Polio” is a syndrome of ruminant animals affecting the central nervous system. Seizures are the most notable sign, progressing quickly to the death of the affected animal without treatment. The underlying cause of the syndrome is a disturbance in thiamine (Vitamin B1) metabolism. Since ruminant animals can assemble B vitamins in their rumens, affected animals do not suffer from a true deficiency of thiamine but rather a functional loss of availability of the substance. Young animals tend to be more susceptible to polio than older animals but affected animals must be old enough to have a functional rumen.
Although the condition may occur without knowledge of the factors involved in promoting the condition, a few things are known to increase the incidence. Elevations of dietary sulfur levels, high sulfur water sources, adding gypsum or ammonium sulfate to the diet, and addition of some grain by-products to the ration have been associated with an increased incidence of the condition.
Treatment requires immediate intravenous treatment with thiamine, and recovery from the seizures is rapid in those animals without severe brain pathology. No blood or other ante-mortem tests are available, and diagnosis is usually made by histopathological examination of the brain tissue.
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Roder, J. and Bickett-Weddle, D., Blackwell’s Five-Minute Veterinary Consult: Ruminant; Scott R.R. Haskell, DVM, editor. 2008 pgs. 720-721.