Viral encephalomyelitis of pigeons: pathology and virus isolation.

A previously unrecorded nervous disease in pigeons was investigated. The disease, characterized by paresis, paralysis of the extremities, head-shaking, and torticollis, is contagious and spreads slowly. The mortality rate of affected pigeons was very high. The disease appeared to spread among pigeon flocks in spring and summer. The predominant gross change in most cases examined was congestion of the visceral organs. Some cases had grayish spots on the pancreas and kidneys. The histologic changes are characterized by neuronal and myelin degeneration with mononuclear cell infiltration and perivascular cuffing. Degeneration of the parenchyma and marked congestion are prominent in the visceral organs. The causal agent, found to be a virus, produced pock lesions on chorioallantoic membranes of developing chick embryos and failed to aagglutinate chicken RBCs. Antisera against Newcastle disease virus and avian encephalomyelitis virus did not neutralize the isolated virus. The virus produced typical signs in experimentally inoculated pigeons.