Toxic Manifestations in Rabbits and Mice Associated with the Virus of Western Equine Encephalomyelitis

Abstract

Animals inoculated with high concentrations of the Western equine encephalomyelitis virus exhibited well-defined toxic manifestations directly referable to the virus particle. The toxin resembled those of other toxigenic viruses in producing a febrile reaction and associated leucopenia after the intravenous inoculation of rabbits. Mice inoculated by the same route died within two days with gross necrotic lesions in the liver. There was no evidence that significant viral multiplication was associated with these latter changes. The toxin, relatively stable at 4 C, was destroyed at 56 C for 30 minutes (a procedure simultaneously effecting a ten-thousandfold reduction in the intracerebral infectivity titre). Neutralization of virus infectivity by specific antiserum also abolished clinical evidence of toxicity. The above results have been incorporated in a discussion on the relationship between viral toxicity and the normal infective process of the same virus.