West Nile virions aligned along myelin lamellae in organotypic spinal cord cultures

Organotypic spinal cord cultures infected with West Nile Virus (WNV) exhibited a remarkable arrangement of virions among lamellae of the myelin sheath. Virions were first observed in neurons and only at day 4 after infection appeared within the myelin lamellae. Virions were observed only in the central myelin, aligned along the interperiod lines and therefore attached to the outer side of the oligodendrocyte membrane. In spite of this peculiar location of the virions, their presence was not associated with severe damage to the axon or to the myelin sheath. The causes of the formation of this viral pattern, its morphological features, and the role which it might have in viral infection in vivo are considered.