A case of acute ascending myelitis which followed the bite of an apparently normal Macacus rhesus monkey is described. The clinical course as well as the pathological changes has been studied and found to be suggestive of a virus cause for the disease. The absence of perivascular demyelinization removes the case from the realm of acute disseminated encephalomyelitis and establishes it more or less definitely as a primary acute infectious myelitis. An extremely important feature of the pathological picture of this disease has been the presence of focal necrosis in the viscera (spleen, adrenals, regional lymph nodes).
Attempts to transmit the disease to Macacus rhesus monkeys, dogs, mice, and guinea pigs, employing glycerinated organs from the human case, proved unsuccessful. By the inoculations of rabbits the presence of a strongly neurotropic, filtrable virus was demonstrated in the patient's brain, cord, and spleen. Following intracutaneous injection of it as derived either from brain and cord or spleen, an experimental disease develops in rabbits which strikingly resembles the human disease in the character of the local lesion, the incubation period, development of urinary retention, and flaccid paralysis of the posterior extremities with cephalad progression, death by respiratory failure, and finally by the occurrence of focal necrosis in the spleen, adrenals, and liver. In attempting to establish the identity of this virus, (the B virus), a consideration of its biological properties excludes the viruses of poliomyelitis, rabies, vaccinia, Virus III disease of rabbits, and the other viruses which are known to produce similar intranuclear inclusion bodies, except perhaps herpes. Although the relationship between the B virus and the virus of herpes must still be determined by cross-immunity tests it has been shown to possess certain properties which warrant consideration of it as a distinct entity.