The pathogenesis and pathology of experimental quaranfil virus infection

Mice were infected intranasally with Quaranfil arbovirus, and killed at intervals from 1 day to 2 mth later. The infection produced clinical signs of neurologic disturbance and a high mortality. The virus could be isolated from the lungs on Days 1-9 and from the brain on Days 1-11 of the infection. Meningoencephalitis developed by Day 5 in the olfactory lobes and spread progressively caudally, involving all regions of the brain by Day 7. The principal features of the inflammatory process were perivascular cuffing, necrosis of neurones and, in the later stages, spongiform degeneration and marked astrocytic and microglial activity. In the lungs after a short and mild exudative phase interstitial pneumonia developed. This was characterized by proliferation of connective tissue cells in interalveolar septa and later by fibrosis.