Simultaneous Distemper and Lymphocytic Choriomeningitis in Dog Spleen and the Sparing Effect on Poliomyelitis

Abstract

While continuing the study of canine distemper in monkeys, evidence accumulated which indicated that our virus-source material was a mixture. This has been verified by the recovery of the virus of lymphocytic choriomeningitis from 4 different samples of dog spleen containing the virus of canine distemper and by its presumptive demonstration in 7 other instances. The present report submits evidence that the virus of lymphocytic choriomeningitis occurs in the dog and to correct our earlier description of canine distemper in the monkey and the sparing effect of distemper on experimental poliomyelitis. Three bacteriologically sterile 20% suspensions of pooled dog spleens taken from separate harvests of canine-distemper virus of the same strain were inoculated intracerebrally in 0.03 cc amounts into groups of mice. A uniform clinical response resembling Traub's description of lymphocytic choriomeningitis followed. Part of one suspension was inoculated subcutaneously into 2 puppies. Fifteen days later these were moribund with canine distemper and were sacrificed. Six mice inoculated with splenic emulsion of one of these puppies also sickened and died. Fourteen of 18 examined mice had lymphocytic chorioiditis. At the same time a considerable number of mice from the same colony were inoculated intracerebrally with dog-spleen suspensions secured from other sources and containing canine-distemper virus, with various other suspected materials and with sterile broth. All remained well. The data of representative groups have been incorporated in Table I as evidence both of the freedom of our stock animals from spontaneous lymphocytic choriomeningitis as well as the presence of a virus, capable of producing the clinical response of lymphocytic choriomeningitis, in the original materials. Three guinea pigs were inoculated subcutaneously (0.5 cc) with one of the pooled dog-spleen suspensions and developed the symptoms of lymphocytic choriomeningitis, emaciation, dyspnea, and conjunctivitis. All 3 died. Two of these were demonstrated to have the lesions of lymphocytic chorioiditis (heavy round-cell infiltrate of the chorioid plexus and liver).