Attempted Production of Vaccinal Encephalitis in Rabbits with a Testicular Virus.

Abstract

The production of vaccinal encephalitis in rabbits is of interest at this time chiefly in view of the prevalence of post vaccinal encephalitis in some European countries. The possible use of the rabbit's brain as a medium for mass production of sterile vaccine (advocated by Levaditi) also adds importance to the question.

A considerable number of European workers have succeeded in producing what they regard as a vaccinal encephalitis in rabbits. Levaditi 1 and his co-workers since 1921 have developed a strain of vaccine virus, known as neurovaccine, which produces regularly on intracerebral injection into rabbits a typical encephalitis with paralytic symptoms and death in 4-7 days. They regard it as a virus adapted to the central nervous system by passage and consider that it has acquired neurotropic properties. They first adapted it to the brain by alternate brain and testicular passage—later omitting the testicular passages. Blanc and Caminopetros 2 found that ordinary calf vaccine passed through the rabbit's cornea and then to the brain was sufficiently adapted to cause a fatal encephalitis. Herzberg 3 produced a vaccinal encephalitis by the intracerebral injection of a virus adapted to the rabbit's testicle.

The great majority of workers, however, have found no adaptation necessary and consider the encephalitogenic property as one inherent in ordinary vaccine virus. Marie, 4 Krumbach, 5 Condrea, 6 Bachman and Bigliere, 7 Burnet and Conseil, 8 Winkler, 9 have all succeeded in producing an encephalitis by the intracerebral injection of ordinary calf vaccine lymph purified by various means. Krumbach found no difference between calf lymph and lapine (vaccinia adapted to rabbit's skin by passage). Condrea was unable to detect any difference between the action of cutaneous and testicular virus in the brain—both producing encephalitis.