Cross–Protection Between Venezuelan Equine Encephalomyelitis and Eastern Equine Encephalomyelitis Virus

Summary Mice were capable of with standing a large challenge dose of virulent Venezuelan equine encephalomyelitis virus and a substantial challenge dose of eastern equine encephalomyelitis virus after immunization with an attenuated 9t strain of VEE virus. This resistance was elicited after administration of the 9t strain by the intraperitoneal, subcutaneous, and respiratory routes, the latter being accomplished by short exposures to aerosols of the attenuated strain. Rabbits and guinea pigs, which were refractory to infections with EEE virus, were protected against lethal doses of the heterologous virulent VEE virus.