Human Venezuelan Equine Encephalitis and Diabetes

Abstract

This chapter reviews the effect of Venezuelan equine encephalitis (VEE) virus on pancreatic beta cells. Experimental studies have been done in several animals and it has been shown that the virus is capable of attacking beta cells. In hamsters, the Trinidad strain produced a massive infection and death occurred very shortly after inoculation; mature virions and viral antigens were found in the beta cells (1). Three months after inoculation of the VEE-attenuated strain TC-83 there was no visible damage to the islets but metabolic studies showed some abnormalities in glucose tolerance tests, although the fasting glycemia levels were not elevated. The insulin content of each pancreas tested was normal but the insulin response to glucose was occasionally depressed (1). The same pattern was described in monkeys by Bowen et al. (2). These investigators reported that in young (2–3 year old) rhesus monkeys infected with the virulent Trinidad donkey strain of VEE virus, the glucose tolerance curves 2, 5 and 10 months after infection were abnormal and that insulin curves showed a progressive diminution of both, basal and glucose-stimulated insulin levels. A normal pancreatic histology and insulin content in these animals were compatible with a defect in insulin release from beta cells.