A New Disease of Moose. II

Abstract

Thomas and Cahn 1 described a new disease of moose (Alces americana americana) in northern Minnesota. The symptoms of the disease were described, with the associated blood picture. Transplanting ticks (Dermacentor albipictis) from an infected moose to guinea pigs and rabbits produced a disease showing identical symptoms, with the same associated blood picture as in the moose. Profound cellular changes in the blood elements and the presence of bacteria were mentioned. The organism was isolated. The cellular changes will be discussed in the final report; the present paper deals with the isolated organism.

The first recognized bacteria-like organism was found in smears of the intestinal contents of ticks engorged with the blood of diseased moose. With a modified Wright stain these organisms showed a capsulated coccoid bacterium. This intestinal content was cultured on dextrose agar, and the organism isolated. A saline suspension of this pure culture was inoculated intravenously into guinea pigs and rabbits, and all of the experimental animals died within 28 hours, exhibiting symptoms similar to those shown by guinea pigs and rabbits infected through the medium of the tick itself. The organism has been repeatedly recovered from the liver, spleen, lungs, heart, kidney, brain, bone marrow and urinary bladder of inoculated and infected animals. This organism has also been inoculated into a bull, a chicken, a ram and a 4-day-old lamb. The chicken and the lamb died with symptoms exactly like those obtained in the guinea pigs and rabbits. In the case of the bull, 5 cc. of the culture was given intravenously. Within one hour after the injection very definite disturbances were noted, including a marked physical depression, listless drooping, labored respiration followed by lung hemorrhages, coughing and bloating.