Clinical manifestations of chronic thiamine deficiency in rhesus monkey.

In the course of multiple episodes of thiamine deficiency in the rhesus monkey, the triad of anorexia, apathy, and hind limb weakness is the earliest clinical manifestation. In later episodes, nystagmus, abducens paresis, midline ataxia, dysmetria, and congestive heart failure are also seen. With the exception of dysmetria, the neurologic signs promptly respond to thiamine administration. Pair-fed controls showed no clinical signs. Neither peripheral neuropathy nor edema was observed. Thiamine-deficiency in the experimental animals was confirmed by blood transketolase assays.