Transmission of measles virus encephalitis to ferrets by intracardiac inoculation of a cell‐associated SSPE virus strain

Ferret fibroblasts infected with a cell-associated strain of subacute sclerosing panencephalitis virus were inoculated into the hearts of ferrets in order to study whether the virus can spread from the blood to the brain in this animal model. Five of 21 inoculated ferrets developed encephalitis 5–7 days later and were sacrificed. Sick animals showed inflammatory lesions in the brain, both perivascular cuffings and infiltration of inflammatory cells in the choroid plexus and meninges. Virus was isolated in cell cultures from various parts of the brain and virus antigen was found by immunostaining, particularly in the cortex. Virus was not detected in inflammatory cells by immunostaining but in situ hybridization with a cDNA probe demonstrated measles virus RNA in neurons and glia cells surrounding perivascular inflammatory cuffings and in a lymph node of one ferret. Ferrets inoculated into the heart with cell-associated SSPE virus seem to be a suitable animal model to study how the virus spreads from the blood to the brain.