Further Studies of the Agent in Intestines of Normal Mice Which Induces Encephalomyelitis

Abstract

Conclusions

Certain additional characteristics have been described of the active agent which is present in the intestines of normal mice and which can induce encephalomyelitis indistinguishable from that of the spontaneous Theiler's disease. Among other findings, it was ascertained that, irrespective of whether mothers harbor virus (by means of artificial, cerebral inoculation or naturally in their intestinal contents), the incitant is not detectable in the intestines of their young from the fetal stage to 12 days of age, but it is demonstrable at the age of 20 days or older. Moreover, at 30 days of age, practically every mouse that has come under observation has yielded specifically active intestinal contents. By some mechanism not as yet understood, old mice harbor less of the agent than do young adults. Finally, in the latter age-group, while the mice carry regularly the active substance in their intestines, it is not at all recoverable from their brains.