Viral Effect Produced by Intestinal Contents of Normal Mice and of Those Having Spontaneous Encephalomyelitis

Abstract

Spontaneous encephalomyelitis of mice was first described by Theiler 1 as a new viral disease. The case incidence among stock Rockefeller Institute mice was shown to be 1 or 2 per 1,000 2 and its existence in Germany 3 and in Japan 4 was reported later. Interest in the malady lies in its similarity in many characters to poliomyelitis 1 , 4 , especially in size of the virus; in its action chiefly on the CNS and the naturally occurring characteristic flaccid paralysis, and in the pathological changes of the CNS. It has been called “poliomyelitis of mice,” although Theiler 1 first demonstrated that there is no relationship between the two in host-susceptibilities and immunological reactions.

In view of the recent discussion on the presence of virus in the feces in poliomyelitis, it was thought desirable to study the intestinal contents of mice having the Theiler disease-syndrome and of normal mice. One of 5 stock, “normal” mice caged together exhibited circling. After 4 days it was killed† and its brain and intestinal tract were removed. 0.03 cc of 10% broth suspension of the brain was injected intracerebrally into each of 4 mice, none of which developed disease. The intestines along with their contents were ground, and 1.75 g diluted with 14 cc broth. This was spun at 2500 rpm for 10 minutes and the supernatant filtered through a Berkefeld “V” candle. One of 4 mice injected intracerebrally with the filtrate developed, after 12 days, flaccid paralysis of both posterior extremities and of the lumbar muscles, and showed the usual signs of Theiler's disease. The transfer from this mouse and later passages to the 6th are tabulated. Further transfers are still being successfully carried out.