The occurrence of vacuolated neurons in the brains of hamsters affected with subacute sclerosing encephalitis following measles or Langat virus infection.

Hamsters infected by the intranasal route with either hamster adapted Langat virus passaged at least 10 times in hamsters and the HNT strain of measles virus passaged 149 times in hamsters, developed subacute sclerotic lesions in the pyriform cortex, and beginning from 2 months after infection, were accompanied by neuronal vacuolation with ballooning of the cytoplasm, especially in parts of the brain in close proximity of the sclerotic lesions. The vacuolated neurons resembled those seen in scrapie, especially of sheep and goats, suggesting a similarity between the effects of slow and subacute viral infections.