Experimental Measles Encephalitis in Normal and Cyclophosphamide-treated Rhesus Monkeys

Three strains of measles virus, a hamster-brain-adapted strain, a low-passage wild Edmonston strain, and an attenuated strain, were inoculated intracerebrally into susceptible measles-free rhesus monkeys. Only the hamster-brain-adapted strain produced encephalitis with morphologic findings similar to those described in subacute sclerosing panencephalitis and quite unlike acute measles encephalitis in man. Severe disease developed in cyclophosphamide-treated animals, and they became moribund within a few weeks after infection. A suppressed replicative cycle in neuronal cells was considered the main factor responsible for the encephalitogenicity of measles virus in primates.