Vacuolar neuronal degeneration in the ventral horns of SCID mice in naturally occurring Theiler's encephalomyelitis.

During a spontaneous outbreak of Theiler's encephalomyelitis severe combined immunodeficient mice developed high morbidity and high mortality. Histological lesions were localized in the ventral horns of the spinal cord and brain stem. The salient features were the severe vacuolar degeneration of neurones and glial cells and the absence of inflammatory cellular infiltrates. The clinical and pathological features of this outbreak indicate that the SCID mouse would be a much improved model for studying the mechanism of poliovirus infection and of virus-induced demyelinating diseases.