Abstract
Kusama 1 , 2 reported the isolation of a gram-positive bacillus as the etiological agent of typhus fever. Later, 3 he reported that immune horse serum (“Typhus Bacillus Immune Horse Serum”) prepared with this bacillus was of distinct value in the prophylaxis and treatment of experimental typhus fever in monkeys. In regard to the etiology of typhus, Kusama differs from the generally accepted view, and his results could not be confirmed by Rix. 4 It seemed of importance to test the action of his serum in guinea pigs infected with a strain of typhus virus kept in this laboratory for 9 months. Kusama kindly placed samples of the serum at our disposal.
The prophylactic and therapeutic action of the serum was tested in guinea pigs which were experimentally infected with a strain of typhus virus during its 20th passage through guinea pigs. The intraperitoneal injection of the virus (1/20 brain from an infected animal) into guinea pigs produced the characteristic typhus fever reaction. After an incubation period of 6 or 7 days the temperature rose to 40° or 40.5° C. and lasted for 10 or 11 days. All animals recovered. some of the animals received 3 cc. of Kusama's immune serum intraperitoneally and others the same amount subcutaneously 4 hours before injection of the virus. The last group received immune serum intraperitoneally 3 days after infection. For control tests 8 guinea pigs received virus alone while 6 were given 3 cc. of convalescent typhus serum subcutaneously 4 hours before infection. Convalescent serum is known to be of definite value in the prevention or modification of experimental typhus fever. In this experiment convalescent serum was obtained from guinea pigs on the 7th day after the temperature had returned to normal.
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